Co-reporter:Hongrui Yao, Zebin Bao, Mingli Shen, Shenglong Zhu, Fuhui Wang
Applied Surface Science 2017 Volume 407(Volume 407) pp:
Publication Date(Web):15 June 2017
DOI:10.1016/j.apsusc.2017.02.245
•Sputtered β-NiAl coating on single crystal superalloy René N5 exhibited good oxidation resistance.•The mechanism for the formation of SRZ in β-NiAl coated single crystal superalloy was analyzed.•Arc ion plated-NiCrO interlayer was fabricated as active diffusion barrier between β-NiAl coating and N5 superalloy, which prevented the formation of IDZ and SRZ, and retarded the coating degradation effectively.•The transformation of NiCrO interlayer into α-Al2O3/Metal/α-Al2O3 sandwich structure was also revealed.Arc ion plated-NiCrO interlayer was fabricated as an active diffusion barrier for microcrystalline β-NiAl coating on Ni-base single crystal René N5 superalloy. The effects of the NiCrO barrier layer on the cyclic oxidation behavior at 1100 °C were investigated. The microstructure of coated specimens was characterized by SEM, XRD, XPS and TEM. The microcrystalline β-NiAl coating without NiCrO barrier layer exhibited good oxidation resistance by forming exclusive α-Al2O3 scales during cyclic oxidation tests at 1100 °C in air. However, the formation of thick interdiffusion zone (IDZ) and secondary reaction zone (SRZ), which accelerated coating degradation, was observed. The NiCrO barrier layer was transformed into α-Al2O3/Metal/α-Al2O3 sandwich structure during vacuum annealing at 1000 °C. The sandwich structure was adherent to the coating and the substrate, prevented the formation of IDZ and SRZ, and retarded the coating degradation effectively during cyclic oxidation tests. The mechanism for the formation of SRZ in NiAl coated single crystal superalloy and the mechanism for the transformation of NiCrO interlayer into α-Al2O3/Metal/α-Al2O3 sandwich structure were discussed.
Co-reporter:Pan Ren, Shenglong Zhu, Fuhui Wang
Corrosion Science 2016 Volume 104() pp:197-206
Publication Date(Web):March 2016
DOI:10.1016/j.corsci.2015.12.012
•A multilayer coating composed of alternating Ni+CrAlYSiHfN and AlxN layers was prepared by reactive sputtering.•This multilayer coating exhibited better oxidation resistance than the NiCrAlYSiHf coating at 1050 °C and 1100 °C.•The micro-hardness of the multilayer coating is higher than that of the NiCrAlYSiHf coating.A multilayer coating, about 40 μm thick, was prepared on superalloy René N5 by reactive sputtering from a NiCrAlYHfSi target and an Al target. The as-deposited coating comprised alternating γ-Ni+CrN+hcp-AlN layers, about 300 nm thick, and hcp-AlN + Al layers, about 400 nm thick. XRD analysis showed that CrN and Al disappeared and β-NiAl was formed in the coating after annealing at 1000 °C. The multilayer coating exhibited good oxidation resistance by forming thin and adherent alumina scales at 1050 °C and 1100 °C, and better spallation resistance of oxide scale than sputtered NiCrAlYHfSi coating.
Co-reporter:Shaojun Hou, Shenglong Zhu, Tao Zhang, Fuhui Wang
Applied Surface Science 2015 Volume 324() pp:1-12
Publication Date(Web):1 January 2015
DOI:10.1016/j.apsusc.2014.10.106
Highlights
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Microcrystalline β-NiAl coating was prepared via magnetron sputtering followed by vacuum annealing.
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Both microcrystalline β-NiAl coating and NiCrAlY coating formed thin and adherent α-Al2O3 scales during oxidation tests.
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Y rich inclusions found in TGO of NiCrAlY coating are believed to be the main cause of much faster scaling rates of the NiCrAlY coating.
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Both inter-diffusion zone and secondary reaction zone were observed in either NiCrAlY coated or NiAl coated specimens.
Co-reporter:Pan Ren, Shenglong Zhu, Fuhui Wang
Applied Surface Science 2015 Volume 359() pp:420-425
Publication Date(Web):30 December 2015
DOI:10.1016/j.apsusc.2015.10.096
Highlights
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An AlN diffusion barrier was prepared between Ni + CrAlXN coating and second-generation superalloys. It exhibited good performance in depressing the interdiffusion at 1000 and 1100 °C for 200 h.
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In the early stage, the evolution of AlN DB is mainly about the amorphous phase crystallizing and the fine grains coarsening.
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At the second stage, (NiCr) and (NiCrCoMo) grains formed at/near the interface began to predominate in the degradation of the AlN diffusion barrier, which result in an undulate interface.
Co-reporter:Xin Wang, Minghui Chen, Shenglong Zhu, Fuhui Wang
Surface and Coatings Technology 2015 270() pp: 314-323
Publication Date(Web):
DOI:10.1016/j.surfcoat.2015.02.014
Co-reporter:Wenbo Li, Shenglong Zhu, Minghui Chen, Cheng Wang, Fuhui Wang
Applied Surface Science 2014 Volume 292() pp:583-590
Publication Date(Web):15 February 2014
DOI:10.1016/j.apsusc.2013.12.012
Highlights
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Glass ceramic composite coatings were prepared by air spray and following firing.
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The Al2O3-glass coating was porous due to the reaction between Al2O3 and glass.
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Cracks formed in the SiO2-glass coating during cooling due to CTE mismatch.
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An intact SiO2–Al2O3-glass coating was prepared on Ti–47Al–2Cr–2Nb alloy.
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The SiO2–Al2O3-glass coating decreased the oxidation rate of the alloy at 900 °C.
Co-reporter:Lijuan Zhu, Shenglong Zhu, Fuhui Wang
Applied Surface Science 2013 Volume 268() pp:103-110
Publication Date(Web):1 March 2013
DOI:10.1016/j.apsusc.2012.12.012
Abstract
Ni + CrAlYSiN nanocrystalline composite coatings and NiCrAlYSi reference coatings were prepared by vacuum arc evaporation on the Ni-based K438 superalloy. The aim of this work is to identify the hot corrosion resistance of the Ni + CrAlYSiN nanocrystalline composite coatings and the NiCrAlYSi coatings. The hot corrosion tests were carried out in a molten salt (75 wt.% Na2SO4 + 25 wt.% NaCl) environment at 900 °C. X-Ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDX) and electron probe microanalysis (EPMA) technique were employed to characterize the coatings and the corrosion scales. The results indicated that both coatings improved the hot corrosion resistance of K438 in the molten salt environment. For the composite coating, the oxide scales were composed of α-Al2O3, Cr2O3 and minor NiCr2O4. No spallation or crack of the oxide scales was observed. Internal oxidation was detected in the outer part of the coating after 100 h corrosion. Internal TiN and AlN formation in the substrate was detected. In contrast, obvious crack/spallation of α-Al2O3 oxide scales on the NiCrAlYSi coating was observed; internal oxidation and sulphidation in the coating and even in the substrate were detected.
Co-reporter:Li Xin, Qian Chen, Yingyuan Teng, Wen Wang, Aiqin Sun, Shenglong Zhu, Fuhui Wang
Surface and Coatings Technology 2013 Volume 228() pp:48-58
Publication Date(Web):15 August 2013
DOI:10.1016/j.surfcoat.2013.04.003
•TiAl(Si)N coatings were deposited on Ti6Al4V by arc ion plating.•Oxidation behaviors of coated alloy were investigated at 650 °C and 750 °C in air.•At 650 °C oxidation resistance of the substrate was improved by all the coatings.•At 750 °C beneficial effects were maintained by TiAlSiN but not by TiAlN coatings.•The better performance of TiAlSiN coatings could be attributed to addition of Si.For improvement of the oxidation resistance of the titanium alloy, multi-layered Ti0.5Al0.5N/Ti0.7Al0.3N and monolayer Ti0.5Al0.5N, Ti0.5Al0.45Si0.05N, Ti0.6Al0.3Si0.1N were deposited on Ti6Al4V alloy by arc ion plating. The isothermal and cyclic oxidation behaviors of the coated alloy were investigated at 650 °C and 750 °C in air. At 650 °C the oxidation resistance of the substrate was significantly improved by all the coatings. At 750 °C, the beneficial effects were maintained by Ti0.6Al0.3Si0.1N and Ti0.5Al0.45Si0.05N but not by Ti0.5Al0.5N and Ti0.5Al0.5N/Ti0.7Al0.3N coatings. The TiAlSiN coating exhibited better oxidation resistance than the TiAlN coating could be attributed to Si addition eliminating defect formation in the TiAlN coating during the oxidation process.
Co-reporter:Xin Wang, Minghui Chen, Shenglong Zhu, Fuhui Wang
Surface and Coatings Technology 2013 Volume 232() pp:6-12
Publication Date(Web):15 October 2013
DOI:10.1016/j.surfcoat.2013.04.044
•Reactions between a glass coating material and α-Al2O3 were investigated.•Crystallization behaviour of the glass coating was characterized.•The interfacial reaction product was identified as gahnite.•The mechanism of the formation and growth of the gahnite interlayer was clarified.•A model of the gahnite interlayer formation and growth was proposed.A SiO2Al2O3ZnOCaO based glass coating on alumina was prepared at 900–1100 °C, and a composite specimen was prepared using a powder mixture of the glass and alumina at 1000 °C. The interfacial reactions between the glass and alumina were investigated using X-ray diffraction, scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy. The glass matrix attacked the alumina inclusions in the glass–alumina composite at first, which led to the formation of a great number of nano-sized gahnite crystallites dispersed in the glass. A discontinuous gahnite interlayer in the coated alumina formed firstly, and then became continuous. In addition, some isolated gahnite crystallites formed in the glass adjacent to the interlayer, and then merged into the interlayer. Finally, the interlayer exhibited a special morphology: the interface between the gahnite interlayer and the glass coating was dentritic, while one between the interlayer and the alumina substrate was flattened.
Co-reporter:Minghui Chen, Mingli Shen, Xin Wang, Shenglong Zhu, Fuhui Wang
Journal of Materials Science & Technology 2012 Volume 28(Issue 5) pp:433-438
Publication Date(Web):May 2012
DOI:10.1016/S1005-0302(12)60079-6
Co-reporter:Minghui Chen, Shenglong Zhu, Mingli Shen, Fuhui Wang, Yan Niu
Materials Science and Engineering: A 2011 528(3) pp: 1360-1366
Publication Date(Web):
DOI:10.1016/j.msea.2010.10.015
Co-reporter:Minghui Chen, Mingli Shen, Shenglong Zhu, Fuhui Wang, Yan Niu
Materials Science and Engineering: A 2011 528(7–8) pp: 3186-3192
Publication Date(Web):
DOI:10.1016/j.msea.2010.12.090
Co-reporter:Mingli Shen, Shenglong Zhu, Fuhui Wang
Thin Solid Films 2011 Volume 519(Issue 15) pp:4884-4888
Publication Date(Web):31 May 2011
DOI:10.1016/j.tsf.2011.01.047
The SiO2–Al2O3–ZrO2–CaO–ZnO glass–ceramic composite coatings (GC), nanocrystalline NiCoCrAlY coating, and their combinations (bi-layer GC/NiCoCrAlY) were prepared on K38G specimens. The thicknesses of the glass–ceramic coatings and the NiCoCrAlY coatings were about 10 μm and 20 μm, respectively. Cyclic oxidation tests were carried out at 1100 °C for 120 cycles. Microstructures of the specimens before and after oxidation tests were characterized by SEM, EDS and XRD. The glass–ceramic coatings with or without a NiCoCrAlY intermediate layer improved the isothermal and cyclic oxidation resistance of the Ni-base superalloy K38G at 1100 °C, and performed better than the NiCoCrAlY coatings. An alumina layer formed at the glass/metal interfaces of the specimens coated by the glass–ceramic coatings with or without a NiCoCrAlY intermediate layer. The NiCoCrAlY intermediate layer was beneficial to the cyclic oxidation resistance of the glass–ceramic coatings.
