Co-reporter:Huijuan Luo, Hejun Li, Qiangang Fu
Computational Materials Science 2017 Volume 127() pp:222-229
Publication Date(Web):1 February 2017
DOI:10.1016/j.commatsci.2016.11.004
•Influences of the vacancy type and the Ag dopant on l-cysteine adsorption are investigated.•The dangling C atom is warped for stable chemisorption in vacancy graphenes.•Two-step energy barrier leads to different adsorption types and adsorption energies.•Room temperature application potential is explored.The understanding of interactions between graphene and biomolecules is of fundamental relevance to the area of nanobiotechnology. Herein, taking l-cys as the probe molecule, its adsorptions on single-vacancy graphene (SV), double-vacancy graphene (DV), Ag doped single-vacancy graphene (AgSV) and Ag doped double-vacancy graphene (AgDV) were investigated using first-principles calculations. SV and AgSV exhibit exothermical chemisorptions while AgDV exhibits endothermical chemisorptions towards l-cys, regardless of the end type. DV shows exothermical chemisorption towards S-end l-cys and endothermical physisorption towards O-end and N-end l-cys. Two-step energy barrier related to initial symmetry broken and structural reorganization leads to differences in adsorption types and adsorption energies. Site-specific immobilization was also revealed. Calculations at 298.15 K and 1 atm reveal that l-cys adsorptions on SV, AgSV, the S-end, O-end adsorptions on DV are thermodynamically favourable. The results could provide guidance for further choice of graphene in bionanotechnological applications.
Co-reporter:Yujun Jia, Hejun Li, Qiangang Fu, Zhigang Zhao, Jiajia Sun
Corrosion Science 2017 Volume 123(Volume 123) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.corsci.2017.03.019
•SAPS ZrC coating with 10% ZrO2 shows significant improvement on ablation resistance.•Decreased C ratio reduced the CO evolution and contributed to the improvement.•The oxycarbide in the coating can attenuate the destructiveness from gas products.•The optimal oxycarbide is ZrCx(0.61 < x < 1.0, y = 0) based on thermodynamic calculations.•Excessive doping of ZrO2 deteriorated the ablation resistance.To improve the ablation resistance of ZrC coating for carbon/carbon (C/C) composites, the C/Zr ratio of the coating was changed by doping ZrO2 using supersonic atmosphere plasma spraying (SAPS). The SAPS ZrC coating with 10 vol.% ZrO2 showed a significant improvement on ablation resistance compared with SAPS ZrC coating without ZrO2 and could protect C/C composites for more than 90 s at heat flux of 2.4 MW/m2. The oxycarbides in the coating attenuated the destructiveness from gas products. The decreased C/Zr ratio and increased relative content of ZrCxOy in the multiphase coating reduced the CO evolution and contributed to the improvement on ablation resistance. An optimal oxycarbide was ZrCx (0.61 < x < 1.0, y = 0) based on thermodynamic calculation. Excessive doping of ZrO2 deteriorated the ablation resistance due to many potential oxygen penetration paths produced during heating and cooling and the probably increased vaporization of the coating.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Le Wang
Materials & Design 2017 Volume 132(Volume 132) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.matdes.2017.07.041
•C/C-HfB2-SiC composites were successfully prepared by precursor infiltration and pyrolysis and reactive melt infiltration.•The prepared composites exhibited good oxidation and ablation performance.•An HfO2 skeleton layer and a borosilicate glassy layer were formed on the surface after ablation under oxyacetylene torch.•The formed ablation products were beneficial for the improvement of ablation performance and thermal retardant ability.C/C-HfB2-SiC composites were prepared by precursor infiltration and pyrolysis followed by reactive melt infiltration. Thermogravimetric analysis showed that C/C-HfB2-SiC composites possessed better oxidation resistance than that of C/C composites. Ablation behavior and thermal retardant ability of C/C-HfB2-SiC composites were investigated using oxyacetylene torch. Compared with C/C, thermal retardant ability of C/C-HfB2-SiC composites was improved by 80.45%, which was 406 °C/mm. After ablation for 90 s, the linear and mass ablation rates of C/C-HfB2-SiC composites were reduced by 73.59% and 77.84%, which were 2.06 μm·s− 1 and 0.129 mg·cm− 2·s− 1, respectively. Two typical morphologies of HfO2 skeleton layer and borosilicate glassy layer were formed after ablation, which were indicated to be beneficial for the improvement of thermal retardant ability and ablation performance.Download high-res image (237KB)Download full-size image
Co-reporter:Qiang Song;Fang Ye;Xiaowei Yin;Wei Li;Hejun Li;Yongsheng Liu;Kezhi Li;Keyu Xie;Xuanhua Li;Laifei Cheng;Litong Zhang;Bingqing Wei
Advanced Materials 2017 Volume 29(Issue 31) pp:
Publication Date(Web):2017/08/01
DOI:10.1002/adma.201701583
Materials with an ultralow density and ultrahigh electromagnetic-interference (EMI)-shielding performance are highly desirable in fields of aerospace, portable electronics, and so on. Theoretical work predicts that 3D carbon nanotube (CNT)/graphene hybrids are one of the most promising lightweight EMI shielding materials, owing to their unique nanostructures and extraordinary electronic properties. Herein, for the first time, a lightweight, flexible, and conductive CNT–multilayered graphene edge plane (MLGEP) core–shell hybrid foam is fabricated using chemical vapor deposition. MLGEPs are seamlessly grown on the CNTs, and the hybrid foam exhibits excellent EMI shielding effectiveness which exceeds 38.4 or 47.5 dB in X-band at 1.6 mm, while the density is merely 0.0058 or 0.0089 g cm−3, respectively, which far surpasses the best values of reported carbon-based composite materials. The grafted MLGEPs on CNTs can obviously enhance the penetration losses of microwaves in foams, leading to a greatly improved EMI shielding performance. In addition, the CNT–MLGEP hybrids also exhibit a great potential as nano-reinforcements for fabricating high-strength polymer-based composites. The results provide an alternative approach to fully explore the potentials of CNT and graphene, for developing advanced multifunctional materials.
Co-reporter:Fengling Zhao, Qiangang Fu, Lu Wang, Yue Liu
Materials Science and Engineering: A 2017 Volume 703(Volume 703) pp:
Publication Date(Web):4 August 2017
DOI:10.1016/j.msea.2017.06.059
SiC nanowires were in-situ synthesised onto SiC coated carbon/carbon (C/C) composites to construct SiC nanowire reinforced magnesium aluminosilicate (SiCnw/MAS) nanocomposites for strengthening and toughening carbon/carbon-lithium aluminosilicate (C/C-LAS) joints. Polymer impregnation pyrolysis (PIP) technique was applied to prepare high purity SiC nanowires. A layer of SiCnw/MAS nanocomposites with ~ 30 µm was achieved between SiC ceramic coating and MAS interlayer via hot-pressing sintering. As a result of debonding, pulling out and deflecting crack mechanisms of the nanowires, fracture pattern was changed from brittle fracture to pseudo-plastic fracture, accompanied by significantly increased shear strength and enhanced work of fracture. The introduced SiC nanowires could dissipate the energy enquired for crack propagation by arresting and deflecting cracks and contribute to the improved mechanical performance. Shear strength and work of fracture of the PIP SiC nanowires reinforced C/C-LAS joints were improved respectively by 94% and 61%, ascribed to the formation of SiCnw/MAS nanocomposites.
Co-reporter:Yue Liu, Qiangang Fu, Yiwen Guan, Beibei Wang, Qingliang Shen
Journal of Alloys and Compounds 2017 Volume 713(Volume 713) pp:
Publication Date(Web):5 August 2017
DOI:10.1016/j.jallcom.2017.04.188
•C/C-SiC-ZrB2 composites were prepared by RMI.•All samples were machined into wedge-shape to simulate the real working condition.•The erosion of the composites was investigated by exposure to oxyacetylene torch.•The ablation mechanism of C/C-SiC-ZrB2 composites was investigated.C/C-SiC-ZrB2 composites with sharp leading edge shape were prepared by reactive melt infiltration, and their ablation behavior was investigated by subjected to the oxyacetylene flame with a heat flux of 2.38 MW/m2 for 60 s. The results show that after adding ZrB2 particles the mass and linear ablation rates of the C/C-SiC composites could be reduced by 36% and 52%, respectively. The ablated regions of the composites can be divided into two regions according the ablated features: brim ablation region and center ablation region. In the brim ablation region, a kind of ‘embedding structure’ of Zr-O-Si glass layer was formed on the surface of the C/C-SiC-ZrB2 composites, and the ablated surface of the C/C-SiC composites was covered by a melting SiO2 layer. In the center ablation region, the molten SiO2 layer cannot resist the intensive impact of high-temperature, speed and pressure oxyacetylene flame, resulting in the failure of the protective coating for C/C-SiC composites. The surface of C/C-SiC-ZrB2 composites was covered by a sintered ZrO2 layer, which acted as an effective oxygen species and heat flux barrier and protected the composites against further ablation, resulting in an excellent configurational stability of C/C-SiC-ZrB2 composites.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Yong-Jie Wang
Corrosion Science 2017 Volume 123(Volume 123) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.corsci.2017.04.014
•Oxyacetylene torch was used to induce a porous surface on C/C composites.•HfC was introduced into SiC coating by pack cementation.•An inlaid interface was constructed between HfC-SiC coating and C/C substrate.•Cyclic ablation from 1750 °C to room temperature was conducted by oxyacetylene torch.•The inlaid interface improved the oxidation and ablation properties of the coating.To enhance the cyclic ablation performance of SiC coating from1750 °C to room temperature under vertical oxyacetylene torch, interface design and HfC additive were combined. A porous surface of C/C composites was firstly constructed by oxyacetylene flame so as to form an inlaid interface after the pack cementation preparation of HfC-SiC coating. After 8 ablation thermal cycles, the mass loss per unit area of the HfC-SiC coating was only 36.47 mg cm−2. Based on thermogravimetric analysis, adhesive strength and thermal expansion test, effect of the inlaid interface on oxidation as well as ablation performance of the HfC-SiC coating was discussed.
Co-reporter:Yue Liu, Qiangang Fu, Beibei Wang, Tianyu Liu, Jia Sun
Ceramics International 2017 Volume 43, Issue 8(Volume 43, Issue 8) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.ceramint.2017.02.008
In order to improve the ablation resistance of carbon/carbon (C/C) composites, SiC-ZrB2 di-phase ceramic were introduced by reactive melt infiltration. The ablation properties of these composites were evaluated by oxyacetylene torch with a heat flux of 2.38 MW/m2 for 60 s. Compared with the pure C/C composites, the C/C-SiC-ZrB2 composites show a significant improvement in the ablation resistance, and the linear and mass ablation rates decreased from 10.28×10−3 mm/s to 6.72×10−3 mm/s and from 3.08×10−3 g/s to 0.61×10−3 g/s, respectively. After ablation test, the flexural strength retentions of the C/C and C/C-SiC-ZrB2 composites near the ablated center region are 39.7% and 81.6%, respectively. The higher strength retention rate of C/C-SiC-ZrB2 composites was attributed to the introduction of SiC-ZrB2 ceramic phases, which have excellent ablation resistant property. During ablation test, an ‘embedding structure’ of Zr-O-Si glass layer was formed, which could act as an effective barrier for oxygen and heat. The oxide ceramic coating could protect the C/C-SiC-ZrB2 composites from further ablation, and thus contribute to retaining the mechanical property of C/C-SiC-ZrB2 composites after ablation.
Co-reporter:Liping Guo, Qiangang Fu, Jia Sun, Chunyu Cheng
Ceramics International 2017 Volume 43, Issue 12(Volume 43, Issue 12) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.ceramint.2017.04.020
The MoSi2-CrSi2-Si/SiC multi-component coating was prepared by two-step pack cementation on carbon/carbon composites. To investigate the effect of water vapor on the anti-oxidation of the coated samples, two kinds of atmosphere (50%H2O-50%O2, 50%O2-50%Ar) were designed for comparison with a total pressure of 1 atm at 1773 K. The results showed that, after being tested for 10 h, the weight loss of the coated samples in O2+Ar and H2O+O2 were 0.243% and 0.436% respectively. The reasons for different weight losses can be attributed to the water vapor, which could degrade the protective ability of the glass layer formed by SiO2 and Cr2O3 and thereby accelerate the oxidation of MoSi2 and CrSi2. Based on the Mulliken analysis calculated by the first principle, the corresponding water vapor corrosion resistance of the prepared coating was in the following order: SiC>MoSi2>CrSi2, which was consistent with the experimental phenomenon.
Co-reporter:Lei Zhuang, Qian-Gang Fu, He-Jun Li
Carbon 2017 Volume 124(Volume 124) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.carbon.2017.09.019
To enhance the bonding strength and oxyacetylene ablation resistance of the ZrB2–ZrC coated C/C–ZrB2–ZrC–SiC composites obtained by the combination of supersonic atmosphere plasma spray (SAPS) and precursor infiltration and pyrolysis (PIP), novel SiC nanowire (SiCnw)/pyrolytic carbon (PyC) core-shell structures are designed and introduced into the coating. Compared to SiC nanowires which are widely added into ceramics, metals and so on, SiCnw/PyC core-shell structures have a better cohesion. Additionally, the bonding strength of coating can be largely improved through the toughening mechanism of SiCnw/PyC structures. After being exposed to oxyacetylene ablation torch, the best ZrB2–ZrC coated C/C–ZrB2–ZrC–SiC specimens with SiCnw/PyC networks possess a linear ablation rate of −0.9 ± 0.5 μm/s and a mass ablation rate of −0.3 ± 0.6 mg/s, while the linear and mass ablation rates of the C/C–ZrB2–ZrC–SiC specimens for comparison are up to 4.2 ± 1.0 μm/s and 1.2 ± 0.8 mg/s, respectively. The significant improvement of oxyacetylene ablation resistance is attributed to a lower surface temperature during ablation, a lower thermal stress in the coating, and a better bonding strength of the coating/substrate interface owing to the introduction of SiCnw/PyC core-shell structures.Download high-res image (175KB)Download full-size image
Co-reporter:Yue Liu, Qiangang Fu, Beibei Wang, Yiwen Guan, Yang Liu
Journal of Alloys and Compounds 2017 Volume 727(Volume 727) pp:
Publication Date(Web):15 December 2017
DOI:10.1016/j.jallcom.2017.08.114
•C/C-SiC-ZrB2 composites were prepared by RMI.•All samples were machined into wedge-shape to simulate the real working condition.•The erosion of the composites was investigated in a simulated solid rocket motor.•The ablation mechanism of C/C-SiC-ZrB2 composites was investigated.In order to improve the ablation resistance of carbon/carbon (C/C) composites, SiC-ZrB2 was infiltrated into them by reactive melt infiltration (RMI). Their ablation behavior with a leading edge shape was investigated in the combustion environment of a simulated solid rocket motor (SRM). The results show that after introducing SiC-ZrB2 ceramic phases into C/C composites, the linear and volume ablation rate of modified leading edge decreased by 26% and 45%, respectively. The high erosion rate of the composites leading edges was mainly attributed to the synergistic effect of thermochemical ablation and mechanical erosion in a high-velocity, high particle concentration two-phase flow of SRM plume environment.
Co-reporter:Yujun Jia, Hejun Li, Qiangang Fu, Jiajia Sun
Surface and Coatings Technology 2017 Volume 309() pp:545-553
Publication Date(Web):15 January 2017
DOI:10.1016/j.surfcoat.2016.12.010
•A ZrC-SiC/ZrC-LaB6/ZrC multilayer coating was prepared by supersonic plasma spraying.•The coated carbon/carbon composites could adapt to the whole ablation process.•The modified ZrC layers provided the oxidation resistance at different temperatures.•The ZrC layer provided a foundation for the system against scouring during ablation.This work proposes a new multilayer coating system containing ZrC-SiC, ZrC-LaB6, ZrC layer with respectively different functions to protect the carbon/carbon (C/C) composites. The coating system overcame the poor oxidation resistance of ZrC coating and weak anti-scouring performance of modified ZrC coating, which could provide the protection for C/C composites through the whole ablation process. After ablation for 40 s, the liner ablation rate of the multilayer coating was − 2.89 ± 0.23 μm/s, decreased by 150.26%, 134.61% and 133.22% relative to the ZrC, ZrC-LaB6 and ZrC-SiC coating, respectively. The coating showed a weight gain, while all the other coatings lost weight after ablation. The good ablation resistance was mainly ascribed to different functions of these layers in the coating system. The ZrC-SiC layer provided oxidation protection during the initial ablation stage by forming a composite oxide of ZrO2-SiO2. In the intermediate stage, the ZrC-LaB6 layer promoted the formation of a stable scale containing (La0.1Zr0.9)O1.95. As the ablation going on, a compact scale containing (La0.1Zr0.9)O1.95 and La2Zr2O7 was formed, which further protected the composites. During ablation, the ZrC layer provided a foundation for the multilayer coating system against scouring.
Co-reporter:Jia Sun, Qian-Gang Fu, Rui-Mei Yuan, Kai-Yuan Dong, Jing-Jing Guo
Materials & Design 2017 Volume 114(Volume 114) pp:
Publication Date(Web):15 January 2017
DOI:10.1016/j.matdes.2016.10.065
•Low-cost sprayed TBCs were deposited on die steel without using C/C composite or refractory lining materials.•LZO TBCs exhibit high corrosion potential due to low content of structural defects.•Shear stress becomes the dominant stress component rather than normal stress in dual- symmetry axis model.•LZO TBCs possessed outstanding thermal-cycling life because of the lowest residual stress.Casting strongly depends on its mold (usually die steel) employing in a cyclic thermal condition at temperature around the melting point of casting metal. To protect die steel from cyclic thermal corrosion at 1000 °C, three different kinds of thermal barrier coatings (TBCs), Al2O3(AO), La2O3-TiO2-Al2O3 (LTA) and La2Zr2O7 (LZO), were deposited on CoNiCrAlY coated steel substrate using a low-cost and time-saving plasma spraying. The corrosion potential and residual stress distribution of coatings were characterized by electrochemical polarization measurement and finite element simulation (FEM). LZO TBCs exhibited the highest corrosion electric potential among three cases. The cycling life was 10, 20 and 50 cycles for AO, LTA and LZO, respectively. FEM results indicated that there appeared the highest residual stress for AO, relatively higher for LTA and the lowest for LZO. Shear stress for AO and LTA cases while axial stress for LZO were the driving force to initiate cracks in coatings. The failure of TBCs originated from their corners and propagated along the direction parallel to the intrinsic layered structure of plasma sprayed coating. The realistic failure modes and the cross-sectional SEM validated this failure mechanism. LZO might be a more promising TBCs compared with AO and LTA for casting application.Download high-res image (177KB)Download full-size image
Co-reporter:Jia Sun, Qian-Gang Fu, Li-Ping Guo, and Lu Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 24) pp:15838-15847
Publication Date(Web):May 31, 2016
DOI:10.1021/acsami.6b04599
A combined silicide coating, including inner NbSi2 layer and outer MoSi2 layer, was fabricated through a two-step method. The NbSi2 was deposited on niobium alloy by halide activated pack cementation (HAPC) in the first step. Then, supersonic atmospheric plasma spray (SAPS) was applied to obtain the outer MoSi2 layer, forming a combined silicide coating. Results show that the combined coating possessed a compact structure. The phase constitution of the combined coating prepared by HAPC and SAPS was NbSi2 and MoSi2, respectively. The adhesion strength of the combined coating increased nearly two times than that for single sprayed coating, attributing to the rougher surface of the HAPC-bond layer whose roughness increased about three times than that of the grit-blast substrate. After exposure at 1200 °C in air, the mass increasing rate for single HAPC-silicide coating was 3.5 mg/cm2 because of the pest oxidation of niobium alloy, whereas the combined coating displayed better oxidation resistance with a mass gain of only 1.2 mg/cm2. Even more, the combined coating could significantly improve the antioxidation ability of niobium based alloy at 1500 °C. The good oxidation resistance of the combined silicide coating was attributed to the integrity of the combined coating and the continuous SiO2 protective scale provided by the oxidation of MoSi2.
Co-reporter:Qian-Gang Fu, Jun-Yi Jing, Bi-Yi Tan, Rui-Mei Yuan, Lei Zhuang, Lu Li
Corrosion Science 2016 Volume 111() pp:259-266
Publication Date(Web):October 2016
DOI:10.1016/j.corsci.2016.05.013
•A SiC nanowire-toughened inlaid transition layer was obtained by a combined method of pre-oxidation treatment and chemical vapor deposition.•Oxidation resistance of the coated samples was improved by the as-obtained transition layer.•The transition layer with an inlaid structure and the pinning of the nanowires could alleviate the mismatch of thermal expansion coefficient between C/C substrate and SiC–MoSi2–ZrB2 coating.To enhance the oxidation resistance of SiC–MoSi2–ZrB2 coating for C/C composites, pre-oxidation treatment and chemical vapor deposition were applied to construct a SiC nanowire-toughened inlaid transition layer between C/C and SiC–MoSi2–ZrB2 coating. The results show that the coating prepared with pre-oxidation and SiC nanowires has better oxidation resistance, which can protect C/C for 124 h at 1773 K in air with the weight loss per unit area of 1.1 mg cm−2. The synergistic effect of the inlaid structure of the transition layer and SiC nanowires plays positive role on alleviating the mismatch of thermal expansion coefficient between C/C and SiC–MoSi2–ZrB2 coating.
Co-reporter:Lei Zhuang, Qian-Gang Fu, Tian-Yu Liu
Corrosion Science 2016 Volume 112() pp:462-470
Publication Date(Web):November 2016
DOI:10.1016/j.corsci.2016.08.010
•The tip of specimen suffered the most severe shear scouring and gas pressure.•High shear scouring and gas pressure resulted in fragmented ceramic oxides.•The addition of UHTCs into C/C contributed to a higher surface ablation temperature.The ablation resistance of wedge-shaped C/C-ZrB2-ZrC-SiC composites was studied under an oxyacetylene torch. Ablation morphologies and phase compositions were examined by SEM and XRD. As exposed to low heat flux of 2.38 MW/m2, a porous and homogeneous ZrC-ZrO2 skeleton generated. With the increasing of heat flux, ceramic oxides at the tip became loose and fragmented instead of sintering together. Besides that, owing to the wedge-shape of the specimen, high gas pressure mainly concentrated at this region. The high gas pressure and strong shear scouring of flame resulted in the limited accumulation of ceramic oxides. This led to an inferior ablation of wedge-shaped C/C-ZrB2-ZrC-SiC composites in high heat flux of 4.18 MW/m2.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Jun-Ling Qu, Hua-Shan Zhou, Ning-Kun Liu
Corrosion Science 2016 Volume 111() pp:667-674
Publication Date(Web):October 2016
DOI:10.1016/j.corsci.2016.06.007
•Surface modification of C/C composites and in-situ grown SiC nanowires were combined.•Bonding strength of Si-Mo-Cr coating was improved by 5.7% and reached 27.8 MPa.•CTE mismatch between Si-Mo-Cr coating and C/C substrate was alleviated.•Thermal cycling test was carried out under parallel oxyacetylene flame.•Thermal stress during high-low temperature cycles was reduced efficiently.Before the preparation of Si-Mo-Cr coating, blasting treatment of C/C composites and in-situ grown SiC nanowires were performed. Compared with the coated C/C composites without SiC nanowires, the bonding strength of Si-Mo-Cr coating was increased by 5.7%, and the mass loss per unit area was reduced by 46.39% after 30 thermal cycles between 1600 °C and room temperature. The performance enhancement can be attributed to the improved bonding strength and the alleviation of mismatch of thermal expansion coefficient between C/C substrate and Si-Mo-Cr coating, thereby decreasing the thermal stress during thermal cycles between high and low temperatures.
Co-reporter:Lei Zhuang, Qian-gang Fu, Bi-yi Tan, Yong-an Guo, Qing-wei Ren, He-jun Li, Bo Li, Jia-ping Zhang
Corrosion Science 2016 Volume 102() pp:84-92
Publication Date(Web):January 2016
DOI:10.1016/j.corsci.2015.09.022
•The ablation resistance of C/C–ZrC–SiC is superior in HF1 but is contrary in HF2.•ZrO2–SiO2 double-structure results in good ablation resistance of C/C–ZrC–SiC in HF1.•Collapse of ZrO2 contributes to poor ablation resistance of C/C–ZrC–SiC in HF2.The ablation behaviour of C/C and C/C–ZrC–SiC composites with cone-shaped holes was studied under an oxyacetylene flame in two heat fluxes. The results showed that C/C–ZrC–SiC composites had a superior ablation resistance in the heat flux of 2.38 MW/m2, mainly owing to the ZrO2–SiO2 with double structure formed on the surface. As ablated in the heat flux of 4.18 MW/m2, the ablation resistance of C/C–ZrC–SiC composites was worse than that of C/C composites since the high temperature corrosion resulted in a heavy evaporation of SiO2 and the left ZrO2 skeleton was easily scoured away by the strong scouring force of flame.
Co-reporter:Yujun Jia, Hejun Li, Lei Feng, Jiajia Sun, Kezhi Li, Qiangang Fu
Corrosion Science 2016 Volume 104() pp:61-70
Publication Date(Web):March 2016
DOI:10.1016/j.corsci.2015.11.030
•La-modified ZrC coating was prepared by supersonic atmosphere plasma spraying.•The oxyacetylene ablation behavior of La-modified ZrC/SiC coating was evaluated.•The coating shows a good ablation resistance under heat flux of 2.4 MW/m2.•La promotes the liquid phase sintering of ZrO2 and the formation of a compact scale.•The protection of the scale results in retaining elemental C in its inner layer.To improve the ablation resistance of carbon/carbon (C/C) composites at ultra-high temperature, La-modified ZrC coating was prepared on SiC-coated C/C composites by supersonic atmosphere plasma spraying. The coating shows a significant improvement on the ablation resistance compared with ZrC coating and could protect C/C composites for more than 120 s under heat flux of 2.4 MW/m2. La acted as a role in promoting the liquid phase sintering of ZrO2 and forming a compact scale with high thermal stability, improving the ablation resistance of C/C composites.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Jun-Ling Qu, Rui-Mei Yuan, He-Jun Li
Journal of Alloys and Compounds 2016 Volume 666() pp:77-83
Publication Date(Web):5 May 2016
DOI:10.1016/j.jallcom.2016.01.124
•Blasting treatment of C/C and CVD SiC nanowires were combined to modify SiC coating.•SiC nanowires were in-situ grew on the pre-blasting treated C/C composites by CVD.•Thermal cycling from 1600 °C to room temperature was conducted by oxyacetylene torch.•Thermal shock performance of the modified SiC coating was improved.•CTE mismatch between the modified SiC coating and C/C substrate was alleviated.To enhance the thermal shock resistance of SiC coating for carbon/carbon (C/C) composites, blasting treatment of C/C substrate and in-situ growth of SiC nanowires by chemical vapor deposition (CVD) were combined before the preparation of SiC coating. Thermal shock test of the SiC coated C/C composites was conducted under oxyacetylene torch from 1600 °C to room temperature. After 15 thermal cycles, the mass loss of the SiC coated C/C composites with only blasting treatment was up to 2.45%, and the C/C substrate was partially exposed in the oxyacetylene torch. In contrast, the mass loss of the SiC coated C/C composites with blasting treatment and CVD SiC nanowires was only 0.9%. The measurement of coefficients of thermal expansion indicated that the combination of blasting treatment of C/C substrate and CVD SiC nanowires could alleviate the mismatch of thermal expansion coefficient between C/C substrate and SiC coating more efficiently, thus improving the thermal shock resistance of SiC coating in combustion environment.
Co-reporter:Lu Li, Hejun Li, Qingliang Shen, Hongjiao Lin, Tao Feng, Xiyuan Yao, Qiangang Fu
Ceramics International 2016 Volume 42(Issue 11) pp:13041-13046
Publication Date(Web):15 August 2016
DOI:10.1016/j.ceramint.2016.05.083
Abstract
To protect carbon/carbon (C/C) composites against oxidation, a SiC-ZrB2-ZrC coating was prepared by the in-situ reaction between ZrC, B4C and Si. The thermogravimetric and isothermal oxidation results indicated the as-synthesized coating to show superior oxidation resistance at elevated temperatures, so it could effectively protect C/C composites for more than 221 h at 1673 K in air. The crystalline structure and morphology evolution of the multiphase SiC-ZrB2-ZrC coating were investigated. With the increase of oxidation time, the SiO2 oxide layer transformed from amorphous to crystalline. Flower-like and flake-like SiO2 structures were generated on the glass film during the oxidation process of SiC-ZrB2-ZrC coating, which might be ascribed to the varying concentration of SiO. The oxide scale presented a two-layered structure ~130 µm thick after oxidation, consisting of a SiO2-rich glass layer containing ZrO2/ZrSiO4 particles and a Si-O-Zr layer. The multiphase SiC-ZrB2-ZrC ceramic coating exhibited much better oxidation resistance than monophase SiC, ZrB2 or ZrC ceramic due to the synergistic effect among the different components.
Co-reporter:Yue Liu, Qiangang Fu, Jiaping Zhang, Lu Li, Lei Zhuang
Journal of the European Ceramic Society 2016 Volume 36(Issue 15) pp:3815-3821
Publication Date(Web):November 2016
DOI:10.1016/j.jeurceramsoc.2016.04.007
Carbon/carbon (C/C) composites were modified with SiC-ZrB2 by reactive melt infiltration (RMI). The erosion resistance of the modified C/C composites, which machined into leading edge to simulate the real working condition, was investigated by exposure to the oxyacetylene torch. The erosion morphology and phase composition were examined by SEM and XRD. After exposure to oxyacetylene torch with a heat flux of 2.38 MW/m2 for 60 s, the modified leading edge was slight damaged with linear ablation rate of 0.013 mm/s and mass ablation of 0.0014 g/s, decreased by 70% and 48% compared to pure C/C composites. During ablation, a homogeneous and dense oxide layer was formed on the front of the leading edge, contributing to enhance the ablation resistance of the modified C/C composites. The ablation mechanism of the C/C-SiC-ZrB2 composites is related to the combined effects of thermochemical ablation by oxidative species and the thermomechanical damage by the shear action of high speed oxyacetylene torch.
Co-reporter:Lei Zhuang, Qian-Gang Fu, Tian-Yu Liu, Bi-Yi Tan
Journal of Alloys and Compounds 2016 Volume 675() pp:348-354
Publication Date(Web):5 August 2016
DOI:10.1016/j.jallcom.2016.03.126
•SiC NWs were in-situ synthesized by precursor infiltration and pyrolysis method.•A PIP-SiC nanowires-toughed silicide coating was fabricated.•PIP-SiC nanowires increased the dynamic oxidation resistance of the coating.•PIP-SiC nanowires enhanced the thermal shock resistance of the coating.A novel precursor infiltration and pyrolysis (PIP) technique was used to in-situ synthesize SiC nanowires (NWs) on C/C composites, and then pack cementation was applied to prepare a silicide coating. The results show that the NWs could not only grow uniformly on the C/C surface but also be synthesized in some microholes through PIP technique. During thermogravimetry tests from 800 °C to 1400 °C in simulated air, the mass loss of the coated specimen decreased from 11.8% to 1.5% after incorporating PIP-SiC NWs. The introduction of PIP-SiC NWs also increased the thermal shock resistance of the coated specimens. After 24 times thermal cycles between room temperature and 1500 °C, the final mass loss reduced from 3.23% to 0.37%. The improvement of thermal shock resistance of the coated specimens was owing to the nanoscale toughening mechanism including pulling-out, debonding and bridging of PIP-SiC NWs. In addition, NWs at the coating/substrate interface could play as a barrier to restrain the propagation of microcrack and thus decreased the size of micocrack.
Co-reporter:Qian-Gang Fu, Jun-Yi Jing, He-Jun Li, Xiu-Xiu Jin, Lei Zhuang, Lu Li
Ceramics International 2016 Volume 42(Issue 3) pp:4212-4220
Publication Date(Web):15 February 2016
DOI:10.1016/j.ceramint.2015.11.095
To improve the oxidation protective ability of SiC–MoSi2–ZrB2 coating for carbon/carbon (C/C) composites, pre-oxidation treatment and pack cementation were applied to construct a buffer interface layer between C/C substrate and SiC–MoSi2–ZrB2 coating. The tensile strength increased from 2.29 to 3.35 MPa after pre-oxidation treatment, and the mass loss was only 1.91% after oxidation at 1500 °C for 30 h. Compared with the coated C/C composites without pre-oxidation treatment, after 18 thermal cycles from 1500 °C and room temperature, the mass loss was decreased by 30.6%. The improvements of oxidation resistance and mechanical property are primarily attributed to the formation of inlaid interface between the C/C substrate and SiC–MoSi2–ZrB2 coating.
Co-reporter:Lu Li, Hejun Li, Xuemin Yin, Hongjiao Lin, Qingliang Shen, Xiyuan Yao, Tao Feng, Qiangang Fu
Journal of Alloys and Compounds 2016 Volume 687() pp:470-479
Publication Date(Web):5 December 2016
DOI:10.1016/j.jallcom.2016.06.159
•SiC-ZrB2-ZrC coating was oxidized at 1773 K under different oxygen partial pressures.•The morphology evolution of oxide scale during oxidation was investigated.•ZrO2 particles presented fibrous denticles under a low oxygen partial pressure.•Two-layered structure was obtained under a higher oxygen partial pressure.•Introduction of ZrB2 and ZrC phases played a positive role in deflecting cracks.The oxidation behavior of SiC-ZrB2-ZrC coating on C/C composites was investigated, basing on the microstructure evolution of oxide scale under different oxygen partial pressures at 1773 K. Similar experiments were conducted in SiC coatings, ZrB2 and ZrC ceramic sheets for comparison. The multiphase coating showed the better oxidation resistance at a higher oxygen partial pressure, and its mass change was 1.34% after isothermal oxidation for 6 h at an oxygen partial pressure of 80,000 Pa. With the increase of the oxygen partial pressure, ZrO2 particles with fibrous denticles were replaced by the aggregations of ZrO2 particles and more SiO2 glass was formed in a short time. The formed SiO2 glass could effectively heal the microcracks of oxide scale. Moreover, the ZrB2 and ZrC phases played an important role in deflecting cracks and restraining the propagation of cracks during oxidation. As the oxygen partial pressure increased, the oxide scale of SiC-ZrB2-ZrC coating became denser, presenting a two-layered structure composed of a SiO2 layer and a Si-O-Zr layer at the elevated oxygen partial pressure.
Co-reporter:Jiaping Zhang, Qiangang Fu, Junling Qu
Ceramics International 2016 Volume 42(Issue 12) pp:14021-14027
Publication Date(Web):September 2016
DOI:10.1016/j.ceramint.2016.06.008
Abstract
Before the preparation of MoSi2–CrSi2–SiC–Si coating, blasting treatment of carbon/carbon (C/C) composites, as a surface modification method, was conducted under oxyacetylene torch. MoSi2–CrSi2–SiC–Si coating was prepared on the treated C/C composites by pack cementation, where an interlock interface was formed between the coating and the C/C substrate. After blasting treatment, the thermal expansion coefficient mismatch between the coating and C/C substrate was alleviated efficiently, and the bonding strength of the coating was increased by 45.6% and reached 26.2 MPa. To simulate the real working condition, thermal cycling test was conducted under oxyacetylene torch from 1600 °C to room temperature to construct an environment of combustion gas erosion. Due to the improvement of bonding strength and the alleviation of thermal expansion coefficient mismatch between the coating and the C/C substrate, thermal cycling performance of MoSi2–CrSi2–SiC–Si coating was enhanced. After 25 thermal cycles, the mass loss of the coated C/C composites without blasting treatment was up to 2.4%, and the C/C substrate was partially exposed. In contrast, the mass loss of the coated C/C composites with blasting treatment was only 1.1%.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Jun-Ling Qu
Ceramics International 2016 Volume 42(Issue 16) pp:18411-18417
Publication Date(Web):December 2016
DOI:10.1016/j.ceramint.2016.08.174
Abstract
SiC coating with a thickness of 50–70 µm was prepared on the surface of C/C composites by in-situ reaction method. The SiC coated C/C composites were then tested in a wind tunnel where a temperature gradient from 200 to 1600 °C could be obtained to investigate their erosion behavior. The results of wind tunnel test indicated that the service life of C/C composites was prolonged from 0.5 to 44 h after applying the SiC coating. After the wind tunnel test, three typical oxidation morphologies, including glassy SiO2 layer, porous SiO2 layer and clusters of honeycomb-like SiO2 grains, were found on the SiC coated C/C composites. With the decrease of oxidation temperature, the amount of glassy SiO2 declined and the thermal stress increased, which induced the cracking followed by the degradation of the SiC coating.
Co-reporter:Huijuan Luo, Hejun Li, Zhenhai Xia, Yanhui Chu, Jiming Zheng, Zhengxiong Hou and Qiangang Fu
RSC Advances 2016 vol. 6(Issue 35) pp:29830-29839
Publication Date(Web):10 Mar 2016
DOI:10.1039/C5RA25599F
Exploring potential applications of transition metal (TM) doped graphene in biomolecular adsorption is of fundamental relevance to the area of nanobiotechnology. Herein, we investigated L-cysteine adsorption on first-row transition metal (Sc–Zn) doped single-vacancy and double-vacancy graphenes (MSVs and MDVs) using density functional theory calculations. Three types of upright adsorption configurations, via unprotonated S-end, O-end and N-end functional groups, were considered. All the MSVs chemically adsorb L-cysteine with no regular variation tendency. MDVs show decreasing chemisorption from V to Co, followed by emergence of physisorption from Ni to Zn. L-Cysteine adsorption on MDVs is weaker than that on MSVs, starting from Mn to Zn. Both the TM dopant and the vacancy type contribute to adsorption tendency. In addition, site-specific chemisorption is revealed. The magnetic behaviour of the adsystems is also interesting. In particular, FeSV, ZnSV and NiSV become magnetic after all three end-type adductions. L-Cysteine adsorption induced distribution of the increasing number of 3d electrons and TM–C interactions could account for the magnetism mechanism. Interesting magnetization patterns of MSVs and MDVs occur in most magnetic chemisorbed systems, exhibiting different mirror symmetries. This study could facilitate applications of TM doped graphenes in biosensing, biomolecule immobilization, magnetic bioseparation and other fields in bionanotechnology.
Co-reporter:Lijuan Zhang, Hejun Li, Kezhi Li, Jianfeng Wei and Qiangang Fu
RSC Advances 2016 vol. 6(Issue 39) pp:32661-32669
Publication Date(Web):24 Mar 2016
DOI:10.1039/C6RA00819D
The hybrid architecture of carbon spheres@nitrogen-doped graphene/carbon nanotubes (CS@N-G/CNT) was synthesized by a hydrothermal and ultrasonic-assisted method. It consisted of one-dimensional CNTs and two-dimensional N-doped graphene (N-G) supporting zero-dimensional carbon spheres (CSs). The electrocatalytic activity of the hybrid CS@N-G/CNT shows a better oxygen reduction reaction (ORR) than CS, CNT, N-G, and CS@N-G in alkaline media. More importantly, it displays both a higher mass activity and better stability than a commercial Pt/C. The high electrocatalytic activity and stable oxygen reduction electrocatalyst could be attributed to the higher surface areas and larger pore volume, as well as the synergistic effects of the different dimensional carbon materials, which was beneficial to the diffusion of the electrolyte and O2 during the ORR.
Co-reporter:Yujun Jia, Hejun Li, Lu Li, Qiangang Fu, Kezhi Li
Journal of Materials Science & Technology 2016 Volume 32(Issue 10) pp:996-1002
Publication Date(Web):October 2016
DOI:10.1016/j.jmst.2016.06.019
•LaB6-doped ZrC coatings were prepared by supersonic atmosphere plasma spraying.•The oxyacetylene ablation resistance of LaB6-doped ZrC coatings was evaluated.•ZrC with 10 vol.% LaB6 shows good ablation resistance under heat flux of 4.18 MW/m2.•A stabilized oxide scale forms and consists of solid particles and molten phase.•Excessive addition of LaB6 deteriorates the ablation resistance.Ablation resistance of monolithic LaB6-doped ZrC coating for SiC-coated carbon/carbon composites by supersonic atmospheric plasma spray was investigated under an oxyacetylene torch with a heat flux of 4.18 MW/m2. Result shows that ZrC coating with 10 vol.% LaB6 has a good ablation resistance compared with pure ZrC, ZrC with 20 vol.% LaB6 and SiC-doped ZrC coating. After ablation for 15 s, the weight is increased by 1.12 mg/s. The good ablation resistance is ascribed to the formation of a stabilized scale which consists of protective La2Zr2O7-containing molten phase and ZrO2 particles keeping the integrity of the coating.
Co-reporter:Yue Liu, Qiangang Fu, Fengling Zhao, Guodong Sun, Hejun Li
Composites Part B: Engineering 2016 Volume 106() pp:59-65
Publication Date(Web):1 December 2016
DOI:10.1016/j.compositesb.2016.06.078
In order to understand thermal fatigue behavior of carbon/carbon (C/C) composites, they were subjected to thermal cycles between 1373 K and room temperature for different times. Their microstructure, mechanical strength and internal friction after thermal cycles were studied. The results show that the flexural strength of C/C composites increased from 69 MPa to 89 MPa after 10 thermal cycles between 1373 K and room temperature, and internal friction increased significantly with the increase of thermal cycles. The improvement of the internal friction and the strength were attributed to the increase of the residual thermal stresses at the interfaces. Further increase in the thermal cycles will reduce the interfacial strength between carbon matrix and fibers due to matrix cracking and the decrease of interfacial bonding strength.
Co-reporter:Wang Lu;Fu Qian-gang;Liu Ning-kun;Sun Jia
Journal of Thermal Spray Technology 2016 Volume 25( Issue 7) pp:1280-1288
Publication Date(Web):2016 October
DOI:10.1007/s11666-016-0456-y
A MoSi2-ZrB2 coating was prepared on SiC-coated C/C composites by supersonic plasma spraying, and the effects of particle diameter and subsequent heat treatment in argon at different temperatures on the adhesion strength were studied. The results show that the MoSi2-ZrB2 coating sprayed with an average powder diameter of 29.2 μm could melt thoroughly and form a dense structure without micro-pore, which results in a relatively good adhesion strength of 11.4 MPa compared with 9.2 and 8.6 MPa of the coatings sprayed with the powder diameter of 58.2 and 35.5 μm. The coating presents a decreasing porosity from 2.2 to 1.5% and an increasing adhesion strength from 11.6 to 16.9 MPa after heat treatment at 800 °C, which is mainly caused by slight sintering of SiO2 and B2O3
Co-reporter:Jun-Ling Qu, Qian-Gang Fu, Jia-Ping Zhang, Peng-Fei Zhang
Vacuum 2016 Volume 131() pp:223-230
Publication Date(Web):September 2016
DOI:10.1016/j.vacuum.2016.06.022
•Pack cementation was proposed to prepare TaB2SiC coating on C/C composites.•Ablation behavior of the TaB2SiC coating was investigated under oxyacetylene torch.•A glassy protective layer of TaSiO was formed on the surface.To protect carbon/carbon (C/C) composites against ablation, a TaB2SiC coating was prepared on their surface by pack cementation. Ablation behavior of the coated C/C composites was investigated under oxyacetylene torch. After ablation for 30 s, the linear ablation rate of the TaB2SiC coated C/C composites was 4.2 μm/s. Compared with the SiC coated C/C composites and bare C/C composites, the linear ablation rate was reduced by 40% and 51%, respectively. During ablation, a mosaic-structured TaSiO glassy layer was formed, playing a positive role in preventing oxidizing species from attacking C/C substrate. Oxidation products of TaB2, existing as “pinning phases” in the coating, induced the deflection of the crack formed by the attack of oxyacetylene torch, which was beneficial to enhance the stability of TaB2SiC coating and improve the ablation resistance.
Co-reporter:Qian-gang Fu, Bi-yi Tan, Lei Zhuang, Jun-yi Jing
Materials Science and Engineering: A 2016 Volume 672() pp:121-128
Publication Date(Web):30 August 2016
DOI:10.1016/j.msea.2016.07.001
In order to improve the mechanical properties of carbon/carbon (C/C) composites, homogeneous and uniform SiC nanowires were in situ grown in low-density 2.5D C/C preform using precursor infiltration pyrolysis method with ferrocene as catalyst. SiC nanowire reinforced C/C composites were obtained via chemical vapor infiltration. The linear nanowires consisted of single crystal β-phase SiC with uniform morphology of about 200 nm in diameter and 100 µm in length. Due to the effect of SiC nanowires, the size of pyrolytic carbon (PyC) grain greatly refined in the process of densification. After introducing SiC nanowires, the flexural and shear strength of the composites increased by 131% and 68%. The strength improvement was attributed to the improvement in the bonding of the fibers/PyC interface, the nanoparticles’ dispersion strengthening effect and the increased energy absorption due to the deflection of cracks, the pullout of SiC nanowires and the break of SiC/PyC microrods.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Jun-Ling Qu, Lei Zhuang, Pei-Pei Wang, He-Jun Li
Surface and Coatings Technology 2016 Volume 294() pp:95-101
Publication Date(Web):25 May 2016
DOI:10.1016/j.surfcoat.2016.03.068
•Pre-blasting treatment as a novel surface modification method was put forward.•C/C composites were blasting treated in different heat flux under oxyacetylene torch.•An inlaid interface between SiC coating and C/C composites was constructed.•Oxidation test from 1750 °C to room temperature was conducted by oxyacetylene torch.•The received inlaid interface enhanced the oxidation resistance of SiC coating.To relieve the mismatch of thermal expansion coefficient and enhance the service reliability of SiC coating efficiently, blasting treatment of C/C composites conducted by oxyacetylene torch, as a surface modification method, was used. SiC coating was prepared on the treated C/C composites by pack cementation, and an inlaid interface with different structures between SiC coating and C/C substrate was achieved. High temperature test was conducted under oxyacetylene torch, and the oxyacetylene flame was parallel to the as-received SiC coated C/C composites. After 5 thermal cycles from 1750 °C to room temperature, a glassy SiO2 protective layer without macro-crack was formed on the surface of the coated C/C composites with pre-blasting treatment in the heat flux of 3.2 MW/m2. The good thermal cycle performance was attributed to the inlaid interface, which could relieve the thermal stress, improve the bonding strength and alleviate the mismatch of thermal expansion coefficient between C/C substrate and SiC coating efficiently.
Co-reporter:Lu Li, Hejun Li, Hongjiao Lin, Lei Zhuang, Shaolong Wang, Tao Feng, Xiyuan Yao, Qiangang Fu
Surface and Coatings Technology 2016 Volume 302() pp:56-64
Publication Date(Web):25 September 2016
DOI:10.1016/j.surfcoat.2016.05.071
•SiC coating was prepared on C/C composite by pack cementation and chemical vapor deposition.•Oxidation behaviors of the SiC coatings prepared by different methods were investigated at 1173 K, 1473 K and 1773 K.•SiC coating prepared by pack cementation showed better oxidation protective ability and superior interface adhesion.SiC coatings were prepared on carbon/carbon composites by pack cementation (PC) and chemical vapor deposition (CVD). The PC coating was composed of hexagonal platelets of α-SiC, while the CVD coating consisted of spherical particles of β-SiC. Their oxidation behaviors were investigated at 1173 K, 1473 K and 1773 K. Compared with the CVD-SiC coating, bubbles appeared in the PC-SiC coating at lower oxidation temperature and the oxide layer was thicker, which might be ascribed to the formation of aluminosilicate glass in the PC-SiC coating. With the increasing temperature, the oxidation behavior of the PC-SiC coating transformed from linear to parabolic with dramatically improved oxidation resistance, which might be attributed to the decreased viscosity of SiO2-rich glass and the good healing effect for cracks. The oxidation protective ability of the CVD-SiC coating was worse than that of the PC-SiC coating, because of the higher viscosity of pure SiO2 glass and the inferior interface adhesion between the coating and the substrate.
Co-reporter:Jia-Ping Zhang, Qian-Gang Fu, Peng-Fei Zhang, Jun-Ling Qu, Rui-Mei Yuan, He-Jun Li
Surface and Coatings Technology 2016 Volume 285() pp:24-30
Publication Date(Web):15 January 2016
DOI:10.1016/j.surfcoat.2015.11.027
•ZrO2 coating was prepared on SiC coated C/C composites by supersonic plasma spraying.•The sprayed ZrO2 coating was heat treated at 2700 °C conducted by oxyacetylene torch.•Voids and cracks in the sprayed ZrO2 coating were eliminated after heat treatment.•Thermal cycles from 2000 °C to room temperature were conducted by oxyacetylene torch.•Thermal cycling performance of the ZrO2 coating was improved after heat treatment.ZrO2 coating was prepared on the surface of SiC coated C/C composites by supersonic plasma spraying. Some defects, such as voids and micro-cracks, were observed on the surface of ZrO2 coating after plasma spraying. A novel heat treatment method conducted by oxyacetylene torch was proposed. Through adjusting the gas fluxes of O2 and C2H2, heat treatment temperature can be attained to the melting point of ZrO2 (about 2700 °C) rapidly, which was expected to eliminate the defects formed in the plasma spraying. Surface roughnesses of the ZrO2 coating before and after heat treatment were 23.14 and 14.39 μm, respectively. Heat treatment smoothed the rough surface of the as-sprayed ZrO2 coating and eliminated the defects (voids and micro-cracks) efficiently. After 8 thermal cycles from 2000 °C to room temperature under oxyacetylene torch, the ZrO2 coating without heat treatment was peeled off with the exposure of needle-like carbon fibers. In contrast, the ZrO2 coating with heat treatment was uniform and the coating thickness remaining unchanged.
Co-reporter:Jia Sun, Qiangang Fu, Liping Guo
Intermetallics 2016 Volume 72() pp:9-16
Publication Date(Web):May 2016
DOI:10.1016/j.intermet.2016.01.006
•Silicide coating was deposited on Nb-based alloy using a two-step method.•HAPC treatment can make different roughness for substrate.•5 h HAPC could produce best NbSi2 layer compatible with MoSi2 outer layer.•A proper HAPC plus spraying can result in a good oxidation resistance.Plasma spraying combined with halide activated pack cementation (HAPC) was used to deposit silicide coating on Nb-based alloy. X-ray diffraction (XRD) and energy disperse spectrum (EDS) indicate the formation of the siliconized NbSi2 transition layer and the sprayed MoSi2 outer layer. NbSi2 layer prepared with HAPC exhibits relatively uneven surface which could promote the deposition of the sprayed MoSi2. The coating specimen with 5 h siliconizing presented the best oxidation resistance with only 0.18% mass gain after 25 h oxidation at 1200 °C in air. The synergistic protection effect, depending on the continuous silica layer formed on the coating surface and the dispersal silica within the coating and interface, is responsible for the excellent oxidation resistance of the coating.
Co-reporter:Fengling Zhao, Qiangang Fu, Le Wang, Xiaoying Nan
Materials Science and Engineering: A 2016 Volume 663() pp:56-63
Publication Date(Web):29 April 2016
DOI:10.1016/j.msea.2016.03.108
Ti-Ni-Si compound was used to join carbon/carbon (C/C) composites by hot-pressing sintering. Effects of high temperature treatment and thermal shock on the bonding strength of Ti-Ni-Si joints were investigated. After the joints were treated for 10 h at 1000 °C, the average shear strength was increased to 30.89±0.75 MPa, which was 30.01% higher than the original ones, accompanied by homogeneous Ti-Ni-Si interlayer with few defects. Fracture toughness of the joints after thermal treated for 5 h possessed significant improvement from 1.44±0.32 to 4.10±0.56 MPa m1/2 attributing to the decrease of free Si and the increase of ternary compound Ti4Si7Ni4 in the interlayer. After heat treatment at 1000 °C for 5 h and thermal shock between 1000 °C and room temperature for 30 times, the average shear strength of those joints increased from 23.76±0.50 to more than 30 MPa. The improvement of the mechanical strength of Ti-Ni-Si joints was attributed to the multi-component diffusion reactions to seal the defects in the Ti-Ni-Si joints during heat treatment and thermal cycling tests. This work could provide new insight to understand strengthening of the bonding between C/C composites instead of weakening after the joints experiencing thermal shock.
Co-reporter:Jia Sun, Qian-Gang Fu, Guan-Nan Liu, He-Jun Li, Yong-Chun Shu, Gao Fan
Ceramics International 2015 Volume 41(Issue 8) pp:9972-9979
Publication Date(Web):September 2015
DOI:10.1016/j.ceramint.2015.04.077
Double-layer thermal barrier coatings (TBCs), including a top ZrO2 layer and an inner CoNiCrAlY layer, were deposited on nickel-based superalloy using supersonic atmospheric plasma spraying (SAPS). Thermal shock resistance of the TBCs between 1200 °C and room temperature was investigated. After thermal shock test, the adhesive strength of the coatings was evaluated through scratch test. The SAPS–TBCs present good thermal shock resistance, exhibiting only 0.26% mass gain up to 150-time thermal cycling. Before thermal cyclic treatment, SAPS–TBCs exhibited a strong adhesion with the absence of the thermally grown oxide (TGO) between out and inner layer. With the increasing of thermal cycles, the TGO layer was formed and its thickness firstly increased and then dropped down. The critical load fell down by about 32% for topcoat–bondcoat adhesion (up to 50 cycles) and 35% or so for TBCs–substrate adhesion (up to 150 cycles) compared to the counterpart of as-sprayed specimens. The strain introduced by the existence of TGO and mixed oxides resulted in a varied adhesion for TBCs on nickel-based alloy during thermal cycling.
Co-reporter:Lu Li, Hejun Li, Yunyu Li, Xuemin Yin, Qingliang Shen, Qiangang Fu
Applied Surface Science 2015 Volume 349() pp:465-471
Publication Date(Web):15 September 2015
DOI:10.1016/j.apsusc.2015.05.028
Highlights
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SiC-ZrB2-ZrC coating was prepared on SiC-Si coated C/C composite by in-situ reaction.
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SiC nanowires were incorporated in the SiC-ZrB2-ZrC coating by electrophoretic deposition.
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The nanowire-toughened coating showed an improved resistance for thermal shock and oxidation.
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The toughening mechanisms of electrophoretically-deposited and CVD nanowires were compared.
Co-reporter:Qiangang Fu, Fengling Zhao, Hejun Li, Han Peng, Xiaoying Nan
Journal of Materials Science & Technology 2015 Volume 31(Issue 5) pp:467-472
Publication Date(Web):May 2015
DOI:10.1016/j.jmst.2014.11.024
Porous C/C–SiC composites were prepared through a two-step chemical vapor infiltration process, and a multi-interlayer joint of Li2O–MgO–Al2O3–SiO2 (LMAS) was applied to join C/C–SiC composites and lithium aluminum silicate (LAS) glass ceramics by means of a vacuum hot-pressing technique. Plenty of SiC whiskers were generated in the pores of low-density C/C composites during chemical vapor deposition process, which is essential to form a zigzag interface structure between C/C–SiC substrate and the LMAS interlayer. The average shear strength of the LMAS joint was improved from 12.17 to 19.91 MPa after changing the composites from high-density C/C composites (1.75 g/cm3) with a CVD-SiC coating to the C/C–SiC composites with a low density (1.48 g/cm3). The improvement of the joint strength is mainly attributed to the formation of the inlay structure at the SiC–C/C and SiC–LMAS interfaces.
Co-reporter:Qian-Gang Fu, Xiao-Ying Nan, He-Jun Li, Xi Chen, Wen-Li Wang
Materials Science and Engineering: A 2015 620() pp: 428-434
Publication Date(Web):
DOI:10.1016/j.msea.2014.09.107
Co-reporter:Jia-Ping Zhang;Qian-Gang Fu;Lei Zhuang;He-Jun Li
Journal of Thermal Spray Technology 2015 Volume 24( Issue 6) pp:994-1001
Publication Date(Web):2015 August
DOI:10.1007/s11666-015-0256-9
Y2SiO5 coating was prepared on the surface of SiC-coated C/C composites by supersonic plasma spraying at different powers of 35, 40, 45, and 50 kW. The microstructures and phase compositions were characterized by scanning electron microscopy and x-ray diffraction, respectively. Roughness of the coating was measured by a confocal laser scanning microscope. Bonding force between Y2SiO5 outer coating and SiC inner coating was measured by a scratch tester. The results show that Y2SiO5 coating prepared at the spraying power of 45 kW possesses the biggest deposition rate, minimum surface roughness (Ra = 11.12 μm), and maximum bonding force (up to 28 N). The linear and mass ablation rates of Y2SiO5 coating prepared at 45 kW are 2.6 μm/s and 0.031 mg cm−2 s−1 in the heat flux of 2.38 MW/m2 under oxyacetylene torch. During ablation, a glassy layer of SiO2 + Y2O3 was formed, acting as a barrier to high-speed gas flow of oxyacetylene flame.
Co-reporter:Qian-Gang Fu, Xiao-Ying Nan, Xi Chen, Wen-Li Wang, He-Jun Li, Yun-Yu Li, Lin-Tao Jia
Materials & Design (1980-2015) 2015 80() pp: 137-143
Publication Date(Web):5 September 2015
DOI:10.1016/j.matdes.2015.04.042
•SiC nanowires were introduced in the interlayer of C/C composite joint by electrophoretic deposition.•The appropriate thickness of SiC nanowire porous layer could resist the crack propagation effectively.•The bonding strength of the joint was improved by introducing SiC nanowires at the interface.In order to improve the bonding strength of the interface between carbon/carbon (C/C) composites and Ti–Ni–Si interlayer, SiC nanowires (NWs) were introduced in the interlayer as reinforcement materials. The SiC NW-reinforced joint was prepared by a two-step technique of electrophoretic deposition (EPD) and hot-pressing. The results show that a porous SiC nanowire layer could be obtained on the surface of C/C composites after EPD at room temperature. With the increase of EPD time, the average shear strength of the joint initially increases and then decreases. The shear strength of the joint with EPD for 30 s reaches a maximum value of 30.44 ± 2.28 MPa, which is 29% higher than that of the joint without SiC NWs. The improvement of the shear strength is primarily attributed to the toughening mechanism of SiC NWs by pull-out and bridging, which could play a positive role in extending the crack propagation path by consuming the applied load.Graphical abstract
Co-reporter:Lu Li, Yanhui Chu, Hejun Li, Lehua Qi, Qiangang Fu
Ceramics International 2014 Volume 40(Issue 3) pp:4455-4460
Publication Date(Web):April 2014
DOI:10.1016/j.ceramint.2013.08.118
Abstract
Periodically twinned 6H-SiC nanowires with fluctuating stems were successfully synthesized on SiC substrate by chemical vapor deposition with ferrocene as the catalyst. The morphology and structures of the products were systematically characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that the nanowires consisted of periodically twinned segments and presented stem-fluctuating morphology, whose diameters fluctuated in the range of 10–150 nm along the axial direction. A model based on vapor–liquid–solid mechanism was proposed to explain the growth of periodically twinned SiC nanowires with fluctuating stems, which revealed that the alternating high-density stacking faults facilitated the formation of stem-fluctuating morphology.
Co-reporter:Xuanru Ren, Hejun Li, Yanhui Chu, Qiangang Fu, Kezhi Li
Surface and Coatings Technology 2014 Volume 247() pp:61-67
Publication Date(Web):25 May 2014
DOI:10.1016/j.surfcoat.2014.03.017
•ZrB2–SiC coating was prepared by in-situ reaction method on SiC-coated C/C.•ZrB2 was synthesized through in situ reaction by reducing ZrO2 using B2O3 and C.•The coating could protect C/C for 550 h with only 0.22% mass loss at 1773 K in air.•The “embedding structure” causes the occurrence of crack deflecting and termination.•Dual protection of SiO2 glass layer and “pinning phases” causes excellent resistance.In order to reduce production cost and effectively improve the oxidation protection ability of the ultra-high temperature ceramics (UHTCs) ZrB2–SiC coating for the SiC-coated carbon/carbon (C/C) composites, a ZrB2–SiC outer coating was prepared by in-situ reaction method on SiC-coated C/C. Instead of costly ZrB2 powder, inexpensive B2O3, ZrO2, Si and C powders were used as raw materials to prepare the outer ZrB2–SiC coating with well-developed microstructures. The ZrB2 and SiC phases in the outer coating were synchronously obtained during the preparation of the coating. The isothermal oxidation behavior of the coated C/C composites at 1773 K was investigated. The double-layer ZrB2–SiC/SiC coating could prevent C/C composites from oxidation at 1773 K for 550 h. During oxidation, a kind of ‘embedding structure’ containing ZrO2 and ZrSiO4 will be formed on the surface of the compound silicate glass layer, which is responsible for the excellent oxidation resistance of the ZrB2–SiC outer coating.
Co-reporter:Zishan Chen, Hejun Li, Kezhi Li, Qingliang Shen, Qiangang Fu
Materials & Design 2014 53() pp: 412-418
Publication Date(Web):January 2014
DOI:10.1016/j.matdes.2013.07.046
•This work investigated the influence of grain size on the wear performance of SiC coating.•The wear resistance and fracture toughness of SiC coating was improved by grain refinement.•TiC can act as perfect heterogeneous nucleus for the nucleation and growth of β-SiC.To improve the wear performance of SiC coating for C/C composites at elevated temperatures, the grain was refined by adding small amounts of titanium, in the raw powders for preparing this coating. The related microstructure and mechanical characteristics were investigated by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and nano-indention. The results show that the grain size of SiC coating decreased from ∼30 μm to ∼5 μm due to the addition of grain refiner. TiC formed by reacting titanium with graphite, can act as perfect heterogeneous nucleus for the nucleation and growth of β-SiC. The wear resistance and fracture toughness of SiC coating was improved by grain refinement. However, the increasing interfaces increased the friction resistance and resulted in the high friction coefficient of fine-grained coating at room temperature. As the temperature rose, oxides layer formed on the surface of fine-grained coating, which can reduce the adhesive wear and decrease the friction coefficient. The fine-grained coating exhibited relative low friction coefficient of ∼0.41 owing to a compact silica film formed on the worn surface at 600 °C, and the wear was dominated by plastic deformation and shear of silica film. The wear of coarse-grained coating was controlled by the fracture of SiC at high temperature.
Co-reporter:Yu-Cai Shan, Qian-Gang Fu, He-Jun Li, Qi Fang, Xue-Song Liu, Ran Zhao, Peng-Fei Zhang
Surface and Coatings Technology 2014 Volume 253() pp:234-240
Publication Date(Web):25 August 2014
DOI:10.1016/j.surfcoat.2014.05.042
•A porous surface structure layer was obtained by oxidation pre-treatment.•An inlaid transition structure was constructed at C/C–coating interface.•Pre-oxidation could enhance the interface bonding strength.•Pre-oxidation could improve the oxidation resistance of the coated samples.To improve the bonding strength and the oxidation resistance of SiC coating by chemical vapor deposition (CVD) for carbon/carbon (C/C) composites, C/C composites were modified by pre-oxidation treatment. It is found that an inlaid transition structure was obtained at the interface between SiC coating and pre-oxidized C/C composites. After pre-oxidation treatment, the interface adhesion strength increases from 23.5 ± 3.2 to 37 ± 2.5 N, and the weight loss of the coated C/C samples is only 0.50% after oxidation at 1773 K for 12 h. The obvious improvement of the bonding strength and the oxidation resistance was mainly attributed to the pre-oxidation of the C/C substrate, forming an inlaid transition layer at the C/C–SiC interface during CVD process.
Co-reporter:Yucai Shan, Qiangang Fu, Shiqi Wen, Hejun Li, Kezhi Li
Surface and Coatings Technology 2014 Volume 258() pp:114-120
Publication Date(Web):15 November 2014
DOI:10.1016/j.surfcoat.2014.09.051
•Pre-oxidation was put forward to treat C/C composites.•A mechanical inlaid structure was constructed at C/C-coating interface.•By pre-oxidation, the coated C/C samples show a better thermal matching performance.•Pre-oxidation can improve the thermal fatigue behavior of the coated C/C samples.Pre-oxidation is used as a treatment to carbon/carbon (C/C) composites for improving the thermal fatigue behavior of Si–Mo–Cr coated C/C composites. Si–Mo–Cr coating was prepared on C/C composites by pack cementation, and the thermal fatigue behavior of the coated samples was studied. After thermal cycling in air between 1773 K and room temperature for 15 times, the mass losses of the coated C/C substrate without and with pre-oxidation were 6.3% and 3.8% respectively. Also, percentages of the remaining flexural strength of the coated C/C substrate without and with pre-oxidation were 71.78% and 82.97%. The improvement of the thermal fatigue properties of the coated samples with pre-oxidation was mainly attributed to the formation of a transition interlocking structure at C/C-coating interface, which is advantageous in alleviating the CTE mismatch between Si–Mo–Cr coating and C/C substrate, decreasing the crack size in the coating.
Co-reporter:Xu Zou, Qiangang Fu, Lei Liu, Hejun Li, Yongjie Wang, Xiyuan Yao, Zibo He
Surface and Coatings Technology 2013 Volume 226() pp:17-21
Publication Date(Web):15 July 2013
DOI:10.1016/j.surfcoat.2013.03.027
Co-reporter:Qian-Gang Fu, Cai-Ge Gu, He-Jun Li, Yan-Hui Chu, Jin-Hua Lu, Lei-Lei Zhang
Materials Science and Engineering: A 2013 Volume 563() pp:133-137
Publication Date(Web):15 February 2013
DOI:10.1016/j.msea.2012.11.053
In order to improve the cohesion strength of hydroxyapatite (HA) coating on carbon/carbon composites, SiC nanowires were introduced as reinforcement material in the coating. The results showed that the coating reinforced by SiC nanowires consisted of flake-like crystals with non-uniform grain size and plate-like crystals. The flake-like crystals were embedded in the plate-like crystals to form an interlocking structure. The thickness of the coating with SiC naowires was 80 μm, thicker than 25 μm without SiC nanowires. Moreover, in the inner layer of coating, HA crystals distributed uniformly in the SiC nanowires which formed a three-dimensional framework structure. Tensile bond test shows that the average tensile strength of the coatings can be increased from 3.96±0.34 to 8.05±0.41 MPa after introducing SiC nanowires. The porous SiC nanowires could form pinning effect at the coating/matrix interface to improve the interface bond, and provide a three-dimensional framework structure in the deposition process to improve the cohesion of HA coating.
Co-reporter:Can Sun, Hejun Li, Huijuan Luo, Jing Xie, Jiaping Zhang, Qiangang Fu
Surface and Coatings Technology 2013 Volume 235() pp:127-133
Publication Date(Web):25 November 2013
DOI:10.1016/j.surfcoat.2013.07.023
•An Y2O3 modified SiC/ZrSiO4 multilayer coating for C/C composites was prepared.•Addition of Y2O3 to coating can restrain the phase transformation of the ZrO2.•Addition of Y2O3 can restrain the consumption of SiO2 glass during oxidation.•The oxidation resistance increases initially and then decreases with the addition of Y2O3.An Y2O3 modified SiC/ZrSiO4 multilayer coating for carbon/carbon (C/C) composites against oxidation at high temperature was prepared by supersonic plasma spraying technique and pack cementation. The microstructure and phase compositions of the coatings were characterized by SEM, EDS and XRD. Oxidation test results show that the coating could protect C/C composites from oxidation at 1823 K in air for 210 h and withstand 25 thermal cycles between room temperature and 1823 K. The excellent protective ability is attributed to the fact that Y2O3 in coating can restrain the phase transformation of the ZrO2 and improve the stability of the SiO2 glass by formation of Y2Si2O7 phase during oxidation.
Co-reporter:Yanhui Chu, Hejun Li, Yongjie Wang, Lehua Qi, Qiangang Fu
Surface and Coatings Technology 2013 Volume 235() pp:577-581
Publication Date(Web):25 November 2013
DOI:10.1016/j.surfcoat.2013.08.028
Co-reporter:Qian-Gang Fu, Bing-Lin Jia, He-Jun Li, Ke-Zhi Li, Yan-Hui Chu
Materials Science and Engineering: A 2012 Volume 532() pp:255-259
Publication Date(Web):15 January 2012
DOI:10.1016/j.msea.2011.10.088
Co-reporter:Han Peng, Qian-Gang Fu, Bing-Lin Jia, He-Jun Li
Materials Science and Engineering: A 2012 Volume 556() pp:607-611
Publication Date(Web):30 October 2012
DOI:10.1016/j.msea.2012.07.034
Carbon/carbon (C/C) composites were joined to lithium aluminum silicate (LAS) glass-ceramic using a joining layer consisting of a SiC transition layer and a multilayer of magnesium aluminum silicate (MAS) and LAS glass-ceramic by a two-step technique of pack cementation and hot-pressing sintering. The microstructures of the as-prepared joint were characterized by scanning electron microscopy and energy dispersive spectrometry. The design of the multilayer structure could provide more possibilities for crack propagation to release the stress in the joint. Results of the thermal shock test showed that the average shear strength of the joined samples increased from 17.9 MPa to 32.6 MPa after 50 thermal cycles between 800 °C and room temperature, which was primarily attributed to the toughening effects of microcracks. However, after 30 thermal cycles between 1000 °C and room temperature, the average shear strength of the joined samples dropped to 14.2 MPa since the crack size was beyond the tolerance of the joint.
Co-reporter:Qiangang Fu, Xu Zou, Yanhui Chu, Hejun Li, Jizhao Zou, Caige Gu
Vacuum 2012 Volume 86(Issue 12) pp:1960-1963
Publication Date(Web):20 July 2012
DOI:10.1016/j.vacuum.2012.04.045
To protect carbon/carbon (C/C) composites against oxidation, a multilayer MoSi2–SiC–B coating was prepared on the SiC-coated C/C composites by a simple and low-cost slurry method. The phase, microstructure and element distribution of the as-received coating were analyzed using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The as-received coating could effectively protect C/C composites against oxidation at 850 °C in air for 100 h without mass loss, which exhibits better oxidation protective ability than the multilayer MoSi2–SiC coating prepared by the same method. At intermediate temperature (850 °C), the excellent oxidation protective ability of the coating is mainly attributed to the formation of the molten B2O3 for sealing the microcracks and preventing oxygen from attacking the C/C substrate.Highlights► A MoSi2–SiC–B multilayer coating was prepared by a simple and low-cost method. ► The coating has a self-healing ability at intermediate temperature. ► The gradually change of the MoSi2/SiC/B ratio could relax the thermal stress. ► The oxidation property could be improved at intermediate temperature.
Co-reporter:Qian-Gang Fu, He-Jun Li, Zheng-Zhong Zhang, Zeng Xie-Rong, Ke-Zhi Li
Corrosion Science 2010 Volume 52(Issue 5) pp:1879-1882
Publication Date(Web):May 2010
DOI:10.1016/j.corsci.2010.01.031
To protect carbon/carbon (C/C) composites against oxidation, a SiC nanowire-toughened MoSi2–SiC coating was prepared on them using a two-step technique of chemical vapor deposition and pack cementation. SiC nanowires obtained by chemical vapor deposition were distributed random-orientedly on C/C substrates and MoSi2–SiC was filled in the holes of SiC nanowire layer to form a dense coating. After introduction of SiC nanowires, the size of the cracks in MoSi2–SiC coating decreased from 18 ± 2.3 to 6 ± 1.7 μm, and the weight loss of the coated C/C samples decreased from 4.53% to 1.78% after oxidation in air at 1500 °C for 110 h.
Co-reporter:Qian-gang FU, Hui XUE, He-jun LI, Ke-zhi LI, Xiao-hong SHI, Hua ZHAO
New Carbon Materials 2010 Volume 25(Issue 4) pp:279-284
Publication Date(Web):June 2010
DOI:10.1016/S1872-5805(09)60033-0
Co-reporter:Fu Qian-Gang, Li He-Jun, Wang Yong-Jie, Li Ke-Zhi, Tao Jun
Surface and Coatings Technology 2010 204(11) pp: 1831-1835
Publication Date(Web):
DOI:10.1016/j.surfcoat.2009.11.026
Co-reporter:Chu Yan-Hui, Fu Qian-Gang, Cao Cui-Wei, Li He-Jun, Li Ke-Zhi, Lei Qin
Surface and Coatings Technology 2010 205(2) pp: 413-418
Publication Date(Web):
DOI:10.1016/j.surfcoat.2010.07.001
Co-reporter:Huijuan Luo, Hejun Li, Qiangang Fu
Chemical Physics Letters (February 2017) Volume 669() pp:
Publication Date(Web):February 2017
DOI:10.1016/j.cplett.2016.12.058
•Hydrogen adsorption on IIA elements (Be, Mg, Ca, Sr) doped graphene is investigated.•Atomic influencing factors of the dopant in the IIA main group are analyzed.•Orbital hybridization and polarization adsorption mechanisms are uncovered.Hydrogen (H2) adsorption on the IIA elements doped double-vacancy graphenes (BeG, MgG, CaG and SrG) was studied by using dispersion-corrected density functional theory calculations. Through investigation of different numbers of hydrogen dockings from two directions, it is found that 1H2/BeG, 1H2/MgG, 8H2/CaG and 8H2/SrG are the most stable adsorption configurations for Be, Mg, Ca and Sr doped graphenes, respectively. Atomic radius, electronegativity and ionization potential of the IIA dopant contribute to the dominating adsorption mechanism under specific H2 concentration. The study would facilitate exploration of high performance graphene-related supports for hydrogen storage.
Co-reporter:Wang Lu, Fu Qian-gang, Zhao Feng-ling
Surface and Coatings Technology (15 March 2017) Volume 313() pp:63-72
Publication Date(Web):15 March 2017
DOI:10.1016/j.surfcoat.2017.01.019
Co-reporter:Lei Zhuang, Qian-Gang Fu
Surface and Coatings Technology (15 April 2017) Volume 315() pp:436-442
Publication Date(Web):15 April 2017
DOI:10.1016/j.surfcoat.2017.02.072
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