Co-reporter:Ganlin Zheng, Gangqiang Zhang, Tongmei Ding, Xianzheng Xiang, Fan Li, Tianhui Ren, Shuhu Liu, Lei Zheng
Tribology International 2017 Volume 116(Volume 116) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.triboint.2017.08.001
•Two kinds of water-soluble ionic liquids (ILs) with the same quaternary ammonium cation but different phosphite or phosphate anions were synthesized, which exhibits favorable water solubility and hydrolytic stability in water-glycol.•Water-soluble ILs with different anions showed distinct tribological properties.•SEM-EDS and L-edge XANES were applied comprehensively to clarify the lubricating mechanism of ILs as additives.Two kinds of novel water-soluble ILs were synthesized and applied as lubricant additives in water-glycol. ILs, as the multifunctional and high efficiency additive, could drastically improve antiwear, friction-reducing and extreme pressure properties of water-glycol. SEM and EDS results indicated that the sample lubricated by PEG600MO phosphate-ammonium IL (P1) acquires higher active element content in the area with heavy wear, while that lubricated by PEG600MO phosphite-ammonium IL (P2) is relatively homogeneous on the worn surface with heavy and mild wear. L-edge XANES results showed that the tribofilm is composed of polyphosphate, and the increase of the polyphosphate chain length could improve the tribological properties. Additionally, the additive concentration, the rubbing time and the load could change the chain length of polyphosphate.
Co-reporter:Zhipeng Li, Tianhui Ren
Tribology International 2017 Volume 109(Volume 109) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.triboint.2016.11.032
•Alkylphosphate-ammonium ionic liquid and alkylphenylborate were prepared as lubricant additives in rapeseed oil;•DBDB and DOPD have outstanding synergistic effects on extreme pressure, friction-reducing and antiwear properties;•The composition and structure of boundary films at the worn surfaces were analyzed by SEM-EDS and XPS.•The tribofilm of the combination of DBDB and DOPD is composed of B2O3, BN, phosphates and/or polyphosphates, organic amine and organic and/or inorganic ammonium, as well as Fe2O3.The tribological properties of di(2-ethylhexyl)phosphate-di(2-ethylhexyl)ammonium ionic liquid (DOPD) and 2-(4-dodecylphenyl)−6-octadecyl-1,3,6,2-dioxazaborate (DBDB) as lubricant additives in rapeseed oil (RSO) were investigated. The results indicate that DBDB and DOPD have outstanding synergistic effects on extreme pressure, friction-reducing and antiwear properties and the synergistic effects are enhanced with the increase of applied load. SEM-EDS and XPS analysis results reveal that the outstanding synergistic effects between DBDB and DOPD originate from the good collaboration of the triboreaction products generated from DBDB and DOPD to form a stable and compact tribofilm with low shearing strength, which is composed of B2O3, BN, phosphates and/or polyphosphates, organic amine and organic and/or inorganic ammonium, as well as Fe2O3.
Co-reporter:Ganlin Zheng, Tongmei Ding, Gangqiang Zhang, Xianzheng Xiang, Yong Xu, Tianhui Ren, Fan Li, Lei Zheng
Tribology International 2017 Volume 115(Volume 115) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.triboint.2017.05.029
•The tribological properties of a P-N type ionic liquid (T672) in synthetic ester (PETO) and water-based emulsion were investigated.•The tribological properties of T672 in PETO and emulsion were not determined by the amount of active elements on the surface of friction pairs.•The content of oligomeric phosphate on the near surface of T672 oil (bulk surface for T672 emulsion) had better correlation with the change of tribological properties.•A three-layer structure model of tribofilms was proposed.This paper focuses on surface analysis of tribofilm formed by a P-N type ionic liquid (trade name VANLUBE 672, abbreviated it as T672) in synthetic ester (pentaerythritol tetraoleate known as PETO) and water-based emulsion. PETO blended with T672 shows better anti-wear, anti-friction and anti-seizure properties than water-based emulsion blended with T672, which could originate from the tribofilm formed on the surface by characterization of SEM-EDS, CLSM and XANES. Tribofilm is composed of oligomeric phosphate and the polymerization and content of oligomeric phosphate could be affected by the medium and friction conditions under different test depths. The improvement of tribological properties is determined by oligomeric phosphate. And the change of oligomeric phosphate content on near surface of PETO (bulk surface for emulsion) is consistent with the change of tribological properties.
Co-reporter:Gang Wang, Zhixiang Zeng, Junjun Chen, Mengya Xu, Jingfang Zhu, Shuan Liu, Tianhui Ren and Qunji Xue
RSC Advances 2016 vol. 6(Issue 47) pp:40641-40649
Publication Date(Web):12 Apr 2016
DOI:10.1039/C6RA03875A
A superhydrophobic surface with ultra low water adhesive force is fabricated on various metals for enhanced corrosion protection. The superhydrophobic surface is constructed by passivated zinc oxide (ZnO) and low surface energy poly(dimethylsiloxane) (PDMS). The process of wettability transformation and corrosion are evaluated by a salt spray test and electrochemical measurement. The superhydrophobic surface is separated layer-by-layer to reveal the function of each layer in corrosion protection. The surface adhesive force is applied as a novel metric for precisely determining the wettability state on the substrate surface. The results reveal that the ultra low water adhesive force of the superhydrophobic surface can effectively suppress water condensation on the metal surface which can suppress the transformation from the Cassie to Wenzel state. The superhydrophobic surface can effectively inhibit corrosion because of the synergistic effect of the triple layered protection system of air, PDMS and ZnO.
Co-reporter:Gang Wang, Zhixiang Zeng, He Wang, Lin Zhang, Xiaodong Sun, Yi He, Longyang Li, Xuedong Wu, Tianhui Ren, and Qunji Xue
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 47) pp:26184
Publication Date(Web):November 12, 2015
DOI:10.1021/acsami.5b08185
To efficiently remove and recycle oil spills, we construct aligned ZnO nanorod arrays on the surface of the porous stainless steel wire mesh to fabricate a porous unmanned ship (PUS) with properties of superhydrophobicity, superoleophilicity, and low drag by imitating the structure of nonwetting leg of water strider. The superhydrophobicity of the PUS is stable, which can support 16.5 cm water column with pore size of 100 μm. Water droplet can rebound without adhesion. In the process of oil/water separation, when the PUS contacts with oil, the oil is quickly pulled toward and penetrates into the PUS automatically. The superhydrophobicity and low water adhesion force of the PUS surface endow the PUS with high oil recovery capacity (above 94%) and drag-reducing property (31% at flowing velocity of 0.38m/s). In addition, the PUS has good corrosion resistance and reusability. We further investigate the wetting behavior of water and oil, oil recovery capacity, drag-reducing property, and corrosion resistance of the PUS after oil absorbed. The PUS surface changes significantly from superhydrophobic to hydrophobic after absorbing oil. However, the oil absorbed PUS possesses better drag-reducing property and corrosion resistance due to the changes of the motion state of the water droplets.Keywords: anticorrosion; biomimetic; drag-reducing; oil/water separation; pours metal mesh; superhydrophobic; superoleophilic; unmanned ship
Co-reporter:Jinhui Zhai, Ajun Wan, Dongli Yu, Tianhui Ren
Journal of Alloys and Compounds 2015 Volume 632() pp:629-633
Publication Date(Web):25 May 2015
DOI:10.1016/j.jallcom.2015.01.212
•Structural, electronic, and optical properties of ordered Si1−xGexC alloys by first principles calculations.•The lattice constants show a linear dependence on the composition x.•The bulk and shear moduli reduce linearly as the increase of composition x.•The indirect to direct band gap transition is result from the symmetry change.•It is proposed that the composition dependent refractive index follows a quadratic equation.The effect of germanium content on the structural, electronic, and optical properties of ordered Si1−xGexC alloys (x = 0, 0.25, 0.5, 0.75, 1) has been systemically investigated in the present work by using first principles calculations based on the density functional theory. The calculated lattice parameters, bulk and shear moduli which exhibit linear dependences on the composition x follow the Vegard’s law and are fitted by linear interpolation. The electronic band structure calculations performed by the application of HSE03 functional reveal that Si1−xGexC alloys are all wide band gap semiconductors, among which Si0.75Ge0.25C and Si0.25Ge0.75C have direct band gaps. The substitution of Ge for Si changes the symmetry of zb-SiC unit cell, giving rise to the indirect to direct band gap transition. The composition dependent static optical functions, such as dielectric constants, refractive index and Plasmon energy are discussed.
Co-reporter:Jianchang Li, Bingji Fan, Tianhui Ren, Yidong Zhao
Tribology International 2015 Volume 88() pp:1-7
Publication Date(Web):August 2015
DOI:10.1016/j.triboint.2015.03.002
●Preparing B–N and B–S–N triazine borate esters as lubricant additives.●The as-prepared additives have high hydrolytic stability.●B–S–N triazine borate ester showed excellent EP property while B–N triazine borate ester hardly owned EP property.●Tribological mechanisms were investigated by using XANES spectroscopy and discussed using the hard and soft acid base (HSBA) principle.The tribological study of N-containing heterocyclic borate esters as lubricating additives had been the research hotspot. In this work, B–N and B–S–N triazine borate esters were synthesized and their antiwear/extreme pressure (AW/EP) properties were studied. Results showed the synthetical additives had good AW performance. However, B–S–N triazine borate ester showed excellent EP property while B–N triazine borate ester hardly owned EP property. The hydrolytic stability of borate ester additives was improved by the formation of coordination of nitrogen to boron. The XANES spectroscopy analysis showed that there was a layer of borate–oxygen–iron inorganics in the tribofilms. The existence of iron sulfate and iron sulfide guaranteed good AW/EP properties of B–S–N triazine borate ester additive in mineral oil.
Co-reporter:Xisheng Fu;Lingguo Sun;Xuguang Zhou;Zhipeng Li
Tribology Letters 2015 Volume 60( Issue 2) pp:
Publication Date(Web):2015 November
DOI:10.1007/s11249-015-0596-0
Two oil-miscible quaternary ammonium phosphites ionic liquids (POPA and PTPA) as lubricant additives were prepared with an environmentally friendly method. The tribological properties were evaluated on a four-ball tester, which suggests that both POPA and PTPA have better extreme pressure, antiwear and friction-reducing properties than that of ZDDP at all test conditions. Furthermore, the worn surfaces were investigated by X-ray absorption near-edge structure (XANES) spectroscopy. Both the P K-edge and L-edge XANES spectra show that the additives decompose and react to form polyphosphates under the boundary lubrication condition, which prevents the direct contact of asperities on the metal surface of the friction pairs. The polymerization degree of phosphate plays a key role in the tribological performances. The higher polymerization degree of polyphosphate leads to better antiwear and friction-reducing properties.
Co-reporter:Yilin Li, Zhipeng Li, Tursunjan Ablekim, Tianhui Ren and Wen-Ji Dong
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 47) pp:26193-26202
Publication Date(Web):03 Nov 2014
DOI:10.1039/C4CP03521F
A rational design strategy of novel fluorophores for luminescent down-shifting (LDS) application was proposed and tested in this paper. Three new fluorophores (1a–c) with specific intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) characteristics were synthesized as LDS molecules for increasing the output short circuit current density (Jsc) of a CdTe solar cell. Photophysical studies of their solution and solid states, and photovoltaic measurements of their PMMA solid films applied on a CdTe solar cell suggested that the specific spectroscopic properties and Jsc enhancement effects of these molecules were highly related to their chemical structures. The Jsc enhancement effects of these fluorophores were measured on both a CdTe small cell and a large panel. An increase in the output Jsc by as high as 5.69% for a small cell and 8.88% for a large panel was observed. Compared to a traditional LDS molecule, Y083, these fluorophores exhibited more superior capabilities of LDS.
Co-reporter:Zhipeng Li, Yilin Li, Yawen Zhang, Tianhui Ren and Yidong Zhao
RSC Advances 2014 vol. 4(Issue 48) pp:25118-25126
Publication Date(Web):20 May 2014
DOI:10.1039/C4RA01672F
Three novel S-containing alkyl phenylboric esters, i.e., DSPB, TSPB and TBPB, were prepared and characterized. Compared with common boric esters, these three additives exhibit significant hydrolytic stability, which can be attributed to their specific molecular structures, in which a phenyl group conjugates with an electron-deficient boron that helps improve the hydrolytic stability of boric esters. The tribological properties were evaluated using a four ball tester, which suggests that all the synthesized compounds act as anti-wear additives and have relatively high load-carrying capacities. In particular, it should be noted that, among the synthesized compounds, DSPB exhibits both anti-wear and friction-reducing properties. Furthermore, the worn surface was investigated by X-ray absorption near edge structure spectroscopy (XANES). The results demonstrate that the resulting tribofilm consists of trigonal and tetragonal coordination boron, iron sulfide and disulfide, and iron sulfate. Moreover, atomic force microscopy (AFM) was used to characterize the morphology of the tribofilm and the large pads elongated and orientated in the sliding direction were observed, which contribute to the anti-wear (AW) and extreme pressure (EP) performances.
Co-reporter:Zhipeng Li, Xiufeng Li, Yawen Zhang, Tianhui Ren, Yidong Zhao, Xiangqiong Zeng, E. van der Heide
Applied Surface Science 2014 Volume 308() pp:91-99
Publication Date(Web):30 July 2014
DOI:10.1016/j.apsusc.2014.04.116
Highlights
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A new hydrolytically stable approach for borate esters was developed.
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Hydrolytic stability and tribological properties of the as-synthesized additive were studied.
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The hydrolytic stability and tribological performances of DBBMT are excellent compared with the normal borate esters and ZDDP, respectively.
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The additive formed a complicated protective film composed of reaction film and adsorption layer on the metal surface of frictional pairs.
Co-reporter:J. C. Yan, X. Q. Zeng, E. van der Heide, T. H. Ren and Y. D. Zhao
RSC Advances 2014 vol. 4(Issue 40) pp:20940-20947
Publication Date(Web):30 Apr 2014
DOI:10.1039/C4RA02267J
Two novel borate ester additives, (2-(2-(bis(2-hydroxyethyl)amino)ethoxy)-1,3,2-dioxaborolan-4-yl)methyl oleate and a tris(2-hydroxyethyl)amine salt of (2-hydroxy-1,3,2-dioxaborolan-4-yl)methyl oleate were prepared and used as anti-wear and extreme pressure agents in rapeseed oil. The tribological performance was evaluated using a four-ball machine. The results show that the additives possess high anti-wear and extreme pressure properties. XANES, XPS and AFM were used to analyse the composition and structure of boundary films at the worn surfaces. The results for the compound and salt of borate esters are compared, and it is shown that the boundary films formed by compound or salt are similar and mainly composed of B2O3.
Co-reporter:Jincan Yan, Xiangqiong Zeng, Emile van der Heide, Tianhui Ren
Tribology International 2014 Volume 71() pp:149-157
Publication Date(Web):March 2014
DOI:10.1016/j.triboint.2013.10.009
•The novel borate additives possess high anti-wear and extreme pressure properties.•The composition and structure of boundary films at the worn surfaces were analyzed.•The additives form a protective film at the rubbed surfaces based on B2O3 and/or BN.•B–N synergetic effect was found in the results.Two novel borate esters, tris (4-dodecylphenyl) borate and 2-(2-(4-dodecylphenoxy)-1, 3, 6, 2-dioxazaborocan-6-yl) ethanol were synthesized and applied as anti-wear and extreme pressure additives in rapeseed oil. The borate esters possess high anti-wear and extreme pressure properties. XANES and XPS were used to analyze the composition and structure of boundary films at the worn surfaces. It is shown that the additives form a protective film at the rubbed surfaces based on B2O3 and/or BN. B–N synergetic effect was found in the results which suggests that tribofilms composed of BN are to be preferred over tribofilms that consists of B2O3.
Co-reporter:Jianchang Li, Zhipeng Li, Tianhui Ren, Xiangqiong Zeng, Emeil van der Heide
Tribology International 2014 Volume 73() pp:101-107
Publication Date(Web):May 2014
DOI:10.1016/j.triboint.2014.01.006
•Preparing two N-containing heterocyclic phenylborate esters as lubricant additives.•The as-prepared additives have high hydrolytic stability.•Synergistic effect between N-containing heterocyclic and benzene was discovered.•The additives display excellent antiwear performances.•Tribological mechanisms were investigated by using XANES spectroscopy.Borate ester compounds are emerging as promising materials for lubricating systems. The main drawback of borate esters however, is the susceptiblity to hydrolysis. In this work, two kinds of N-containing heterocyclic borate esters were synthesized. Their hydrolytic stability and tribological properties as lubricant additives in rapeseed oil were evaluated. The results showed that these borate esters not only possessed promising tribological properties, but also had high hydrolytic stability. Thermal films and tribofilms were investigated by using X-ray absorption near-edge structure (XANES) spectroscopy. Surface analysis indicated that thermal films were mainly composed of adsorbed films and thermo-chemical reaction products. Tribofilms were mainly constituted by BN, B2O3 and organic B.
Co-reporter:Yawen Zhang;Xiangqiong Zeng;Hua Wu;Zhipeng Li
Tribology Letters 2014 Volume 53( Issue 3) pp:533-542
Publication Date(Web):2014 March
DOI:10.1007/s11249-013-0292-x
A novel borate ester containing heterocyclic group, 2,5-bis((2-((6-octadecyl-1,3,6,-dioxazaborocan-2-yl)oxy)propyl)thio)-1,3,4-thiadiazole (BDOT), was prepared and characterized. Its tribological properties and synergistic effect with zinc dialkyl dithiophosphate were evaluated using a four-ball tribometer. The results show that the novel borate additive possesses excellent anti-wear and friction-reducing properties compared with the performance of ZDDP. BDOT combined with ZDDP has a synergistic effect on the tribological properties, especially for the friction-reducing performance. The chemical state of nitrogen, boron and sulfur in thermal films and tribofilms was analyzed by XPS and XANES. XPS analysis suggests that the additive forms a protective film on the rubbing surfaces which is composed of B2O3, BN, FeSO4, FeS2 and Fe2O3. However, the B K-edge XANES shows that no BN was detected in the film. The synergistic effect between BDOT and ZDDP may be due to the formation of right concentration of FeS and FeSO4 in the tribofilm.
Co-reporter:Yilin Li, Tianhui Ren, Wen-Ji Dong
Journal of Photochemistry and Photobiology A: Chemistry 2013 Volume 251() pp:1-9
Publication Date(Web):1 January 2013
DOI:10.1016/j.jphotochem.2012.10.002
A series of triphenylamine-based aromatic cyano compounds have been synthesized as red-emitting fluorophores with large Stokes shifts in both solution (>100 nm in CHCl3) and solid state (>150 nm in film). Intramolecular charge transfer (ICT) properties of the synthesized compounds are examined using UV–Vis absorptions, photoluminescence measurements and solvatochromic studies. Our studies suggest that Stokes shifts of these compounds can be fine-tuned by manipulating the ICT strength between donor and acceptor with various electronic donating groups, and the largest Stokes shifts are typically associated with compounds that have the strong ICT characters. The observed spectroscopic properties of the compounds are consistent with theoretical calculations using density function theory (DFT) or time-dependent density function theory (TD-DFT). The calculations suggest that the ICT occurs from localized HOMO to localized LUMO with magnitudes of 60–80%. The relative quantum yields of these fluorophores in solution are various and highly solvent dependent. In solid state, the quantum yields of the compounds are significantly increased and some can reach to 0.40.Graphical abstractHighlights► The triphenylamine-based aromatic cyano fluorophores were synthesized as wavelength-shifting materials. ► They show specific spectral properties with absorbance from UV to 550 nm and emission around 600 nm. ► Large Stokes shifts were due to the strong intramolecular charge transfer (ICT) effect during excitation. ► The Stokes shift can be fine-tuned by the ICT character between different donor and acceptor groups. ► Solid state spectra were studied.
Co-reporter:Huan Chen;Jincan Yan;Yidong Zhao;Lei Zheng
Tribology Letters 2012 Volume 45( Issue 3) pp:465-476
Publication Date(Web):2012 March
DOI:10.1007/s11249-011-9910-7
A series of novel long-chain dimercaptothiadiazole derivatives are prepared and used as antiwear (AW) and extreme pressure (EP) additives in vegetable oil, and their tribological performance is tested by using a four-ball tester. In order to understand the friction process further, X-ray absorption near edge structure spectroscopy is adopted to analyze the chemistry of tribofilms under AW/EP regime, and meanwhile thermal films are also considered for comparison. These derivatives are capable in improving the tribological characteristic of the base stock, and disubstituted derivatives are more effective than other derivatives. Though disubstituted derivatives and disubstituted polysulfur derivatives all fail in improving tribological performance at 0.1 wt%, they are still helpful at other additive concentrations. All these long-chain thiadiazole derivatives, in particular the disubstituted polysulfur ones, are good at improving the EP characteristic of the base colza oil. Thermal films generated from these derivatives are composed of ferrous sulfate and a small amount of adsorbed organic sulfide. During the heating process, these long-chain derivatives easily undergo thermal oxidation to generate high-valent sulfate on the metal surface. Ferrous sulfide is the main component of tribofilms generated by these derivatives, while ferrous sulfate in these films almost vanishes at 1.0 wt%. These long-chain derivatives tend to react with metal surface to generate low-valent sulfide under rubbing conditions. On the other hand, ferrous sulfide is also the main component of EP films generated by monosubstituted derivatives and disubstituted polysulfur derivatives at 1.0 wt%. But the EP films formed by disubstituted derivatives are composed of ferrous sulfide and ferrous sulfate.
Co-reporter:Rui Qiao, Jing Li, Hua Wu, Tianhui Ren, Yidong Zhao, Chenyan Ma
Applied Surface Science 2011 Volume 257(Issue 9) pp:3843-3849
Publication Date(Web):15 February 2011
DOI:10.1016/j.apsusc.2010.11.046
Abstract
The additives, laurylamino-methylthio-1,3,5-triazine-2,4-dithiol (referred to as TRLA) and diisooctylamino-methylthio-1,3,5-triazine-2,4-dithiol (referred to as TREA), were prepared in our laboratory. The products were characterized by means of infrared spectroscopy (IR) and elemental analysis. Their tribological behaviors as additives in raped seed oil and diester were evaluated using four-ball friction and wear testers as well. The results suggest that all the synthesized compounds have excellent tribological behaviors and they were compared with sulfurized isobutene (referred to as SIB) which is a commercial additive. The results show that they have good tribological properties. The two additives were investigated on thermal films and tribofilms by using X-ray absorption near edge structure (XANES) spectroscopy. The results of surface analysis reveal that the thermal films formed from TREA and TRLA in rape seed oil (referred to as RSO) and diester (referred to as DE), all are consist of iron sulfate; under mild AW conditions, the tribofilms from TRLA and TREA in DE is mainly composed of FeS, while the tribochemcal film from TRLA in RSO is mainly composed of iron sulfite; under EP-1 (the maximum non-seizure load) conditions, the tribochemical films from TRLA and TREA in RSO and DE mainly consist of FeS and FeSO4; under EP-2 (nearly weld load) conditions, the tribochemical films from TRLA and TREA in RSO and DE mainly consist of FeS.
Co-reporter:Haibing Ma, Jing Li, Huan Chen, Guangzhi Zuo, Yi Yu, Tianhui Ren, Yidong Zhao
Tribology International 2009 Volume 42(Issue 6) pp:940-945
Publication Date(Web):June 2009
DOI:10.1016/j.triboint.2009.01.004
Two phosphates were synthesized and their tribological properties as water-soluble lubricant additives were evaluated by using four-ball tester. The micro/nano-scale chemical characteristics of tribofilms and thermal films formed from these additives in different conditions were explored by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) spectroscopy. The results show that the additives have better anti-wear and friction reducing properties than the oleate solution at higher load. Surface analysis results indicate that tribofilms are mainly composed of absorbed layer and chemical reactant layer, in which phosphorus exists in the form of adsorbed molecule, phosphate or polyphosphate, and sulfur in the form of alkyldisulfide, sulfide and sulfate. As to the thermal films, phosphate (or polyphosphate) and sulfate are detected as the main components. The anti-wear and friction-reducing performances can be ascribed to the formation of films on the metal surface, and the mechanism of the process of molecules adsorption, new compounds production through tribochemical reactions, film formation and destruction.
Co-reporter:Jing Li, Haibing Ma, Tianhui Ren, Yidong Zhao, Lei Zheng, Chenyan Ma, Yong Han
Applied Surface Science 2008 Volume 254(Issue 22) pp:7232-7236
Publication Date(Web):15 September 2008
DOI:10.1016/j.apsusc.2008.05.298
Abstract
Two organic polysulfides, dipropyl trisulfide (DPTS) and 3,5-diisopropyl-1,2,4-trithiolane (DIPTT) in mineral oil (MO) and synthetic diester (DE) were investigated on thermal films and tribofilms by using X-ray absorption near edge structure (XANES) spectroscopy. The results of surface analysis reveal that the thermal films formed from MO for two additives are consist of sulfate and sulfite, while the distinct composition of the films from DE implies the different sensitivity to oxygen between two compounds. As to the tribofilms, “hydrosulfite-like compound” is differentiated from sulfite and FeSx (1 < x < 2) is detected in low energy region from DPTS/MO, as well as a lower concentration of DPTS/DE. At a high concentration in DE, the surface of sample for DPTS is full of iron sulfide. With regard to DIPTT, iron sulfite is the exclusive oxidized form of sulfur instead of “hydrosulfite-like compound” in the tribofilms, which is an evidence suggesting a mechanism involving a role played by a thiyl radical.
Co-reporter:Xiangqiong Zeng, Jing Li, Xuedong Wu, Tianhui Ren, Weimin Liu
Tribology International 2007 Volume 40(Issue 3) pp:560-566
Publication Date(Web):March 2007
DOI:10.1016/j.triboint.2006.05.005
Two ashless and non-phosphorus hydroxyl-containing dithiocarbamate-triazine compounds, 2,4,6-tri[N,N-di-n-butyldithiocarmate-(2′-hydroxyl)-propionylthio]-1,3,5-s-triazine (LDBA) and 2,4,6-tri[N,N-di-i-octyldithiocarmate-(2′-hydroxyl)-propionylthio]-1,3,5-s-triazine (LDIOA), were prepared and their tribological behaviors as additives in rapeseed oil (RSO) were evaluated using a four-ball tester. Thermal degradation tests were conducted to identify their thermal stabilities using a thermo-gravimetric analyzer. The worn surfaces of the steel balls were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). The results indicate that the additives possess high thermal stabilities and good load-carrying capacities. Moreover, they both have good anti-wear and friction-reducing property at relatively high concentration (>1.5 wt%) and under all test loads. The results of XPS analyses illustrate that the prepared compounds as additives in RSO forms a protective film containing inorganic sulfide, sulfate, oxidized compounds and organic nitrogen-containing compounds on the metal surface during the sliding process.
Co-reporter:Wu Hua, Li Jing, Yi Hongling, Zeng Xiangqiong, Lv Lingbo, Ren Tianhui
Tribology International 2007 Volume 40(Issue 8) pp:1246-1252
Publication Date(Web):August 2007
DOI:10.1016/j.triboint.2007.01.024
The diester-containing polysulfides were synthesized and their anti-wear (AW) and friction-reducing behaviors as additives in HVIW H150 base oil were evaluated using a four-ball tester. The copper corrosion test was conducted to identify their anti-corrosion property. The nature of the film formed in the rubbed surface was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Based on the experimental results, diester-containing polysulfides show good anti-corrosion properties and excellent AW abilities similar to that of ZDDP. The results of XPS analyses illustrate that an S-containing inorganic layer, generated by the reaction of diester-containing polysulfides with the metallic surfaces, mainly contains sulfate, sulfite and little sulfide, and there exists a polymer film protective layer over the inorganic layer surface.
Co-reporter:Hua Wu;XiangQiong Zeng;LingBo Lu
Science Bulletin 2007 Volume 52( Issue 2) pp:194-199
Publication Date(Web):2007 January
DOI:10.1007/s11434-007-0011-9
Two di-n-butyl dithiocarbamate derivatives were easily synthesized. Their tribological performances as lubricating oil additives in rapeseed oil were evaluated using a four-ball machine, and their chemistry of films was analyzed with X-ray absorption near-edge spectroscopy (XANES). The results indicate that the two compounds possess excellent anti-wear property and good load-carrying capacity. According to the XANES results, for the thermal films, the outer surfaces are mainly composed of N, S-containing polymer and ferric sulfate, and the near-surface and the bulk are composed of ferrous sulfate, while for the anti-wear films, the outer surfaces are only composed of ferric sulfate, but the near-surface and the bulk are mainly composed of ferrous sulfate.
Co-reporter:Xiangqiong Zeng, Hua Wu, Hongling Yi, Tianhui Ren
Wear 2007 Volume 262(5–6) pp:718-726
Publication Date(Web):28 February 2007
DOI:10.1016/j.wear.2006.08.004
Three novel phosphorus-free triazine derivatives, referred to as ZOO, ZOS and ZDION, respectively, were synthesized. Their thermal stabilities and anticorrosive properties were investigated. Their tribological behaviors as additives in rapeseed oil were evaluated using four-ball friction and wear testers as well. The results suggest that all the synthesized compounds have good thermal stability, corrosion inhibiting ability and excellent tribological behavior. That is, ZOS has the best extreme pressure, antiwear and friction-reducing properties under a wide range of test conditions. And, ZOO generally possesses excellent load-carrying capacity and good antiwear and friction-reducing abilities. However, ZDION shows poor antiwear effectiveness in rapeseed oil, though it is capable of improving the load-carrying capacity and friction-reducing ability of the base stock under high concentration (>1.5 wt.%) and low load (<392 N). The worn surfaces of the steel balls were observed using a scanning electron microscope coupled with an energy dispersive spectrometer (SEM/EDS) and X-ray photoelectron spectroscope (XPS). It is supposed that the synthetic additives adsorb and react with the steel surfaces during the rubbing process and generate a surface protective film composed of sulfate, sulfide, iron oxide and N- and/or O-containing organic compounds, which accounts for the better tribological behaviors of the base stock containing the synthetic additives as compared with the base stock alone.
Co-reporter:Chao Qiu, Sheng Han, Xingguo Cheng, Tianhui Ren
Thermochimica Acta 2006 Volume 447(Issue 1) pp:36-40
Publication Date(Web):1 August 2006
DOI:10.1016/j.tca.2006.01.014
Several typical sulfides were selected and dissolved in hydrotreated base oil, and the antioxidant activities of sulfides studied by rotary bomb oxidation test (RBOT), isothermal pressurized differential scanning calorimetry (PDSC) and non-isothermal PDSC. Four characteristic indexes of constant heating-rate PDSC were chosen and normalized to a comprehensive index by a new method. The sequence determined by the comprehensive index accords partly to the sequence determined by RBOT and accords well with the results reported. The antioxidant activity of sulfide increases with the number of sulfur atoms. Sulfide with long chain has good antioxidant activity, and the antioxidant activity of cyclic sulfides is poor. The method of normalizing the data is useful to determine the oxidation performances of samples, especially when the antioxidant activities vary greatly.
Co-reporter:Zeng Xiangqiong, Shao Heyang, Rao Wenqi, He Zhongyi, Ren Tianhui
Wear 2005 Volume 258(5–6) pp:800-805
Publication Date(Web):February 2005
DOI:10.1016/j.wear.2004.09.067
A novel ashless and non-phosphorus oil-soluble compound, 2,4,6-trioctylthio-1,3,5-triazine(OTT) was synthesized with the reaction of cyanuric chloride and sodium octyl mercaptan in tetrahydrofuran at reflux temperature for 8 h. The tribological properties of OTT and octylthiol(OT) as additives in a liquid paraffin were evaluated and compared using both a four-ball wear tester and a four-ball EP wear test machine. The results show that OTT behaves extremely better than OT as anti-wear and friction-reducing additive, while OT exhibits more excellent extreme pressure property. The element composition and chemical state of the films generated on steel counterface were investigated with a scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). It was found that tribological reaction occurred during the rubbing process and a protective film containing FeS, FeSO4 and some organic nitrogen compounds was formed on the worn surface.
Co-reporter:Weiqiang Zhan, Yuping Song, Tianhui Ren, Weimin Liu
Wear 2004 Volume 256(3–4) pp:268-274
Publication Date(Web):February 2004
DOI:10.1016/S0043-1648(03)00372-7
Three novel ashless triazine–dithiocarbamate derivatives, which are potential environmentally friendly oil additives, were synthesized. Their tribological properties as additives in rapeseed oil (RSO) were evaluated using a four-ball tester. Their anticorrosive properties and thermal stabilities were also investigated. The results indicate that the three novel triazine–dithiocarbamate compounds possess excellent load-carrying capacity, good corrosion inhibiting performance and high thermal stability. Although these additives show friction-reducing property at high additive concentration (5 wt.%), they have friction increase and wear promote natures in most cases. The elemental composition and chemical state of the antiwear films generated on steel counterface were investigated with scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). It was found that the synthetic additives reacted with the counterface metal and generated a surface protective film consisting of sulfate, FeS and absorbed compounds containing organic-N.
Co-reporter:Sheng Han, Peng Wang, Yuhong Wang, Yuping Song, Tianhui Ren
Process Safety and Environmental Protection (January 2010) Volume 88(Issue 1) pp:41-46
Publication Date(Web):1 January 2010
DOI:10.1016/j.psep.2009.09.002
Alkyl methacrylate–maleic anhydride–alkyl methacrylate terpolymers (MR1–MA–MR2) is one of the widely used cold flow improver. In order to develop more efficient MR1–MA–MR2, it is necessary to study the crystallization behavior of n-alkanes when adding MR1–MA–MR2 into diesel fuel. In this paper, MR1–MA–MR2 is prepared by the reaction of long-chain alkyl methacrylate (MR1), maleic anhydride (MA), and short alkyl methacrylate (MR2). The diesel fuel before and after adding MR1–MA–MR2 is in situ filtrated at its cold filter plugging point (CFPP) in a manual CFPP apparatus. Extensive measurements of composition variation of n-alkanes are done by gas chromatograph and the results are compared. The experimental results show that after adding MR1–MA–MR2, the concentration distribution of n-alkanes in the filtrate is wide and arranges from 8 to 26, and mainly centralizes from 10 to 19. For the precipitate, the concentration distribution of n-alkanes gets richer in the lighter n-alkanes and poorer in the heavier n-alkanes. The concentration distribution of n-alkanes in the crystal solid shows a decreasing trend, especially with high carbon number n-alkanes (heavier than C20). About 60–70% of the residual crystal solid is composed of non-paraffins such as isoparaffin, naphthene and other components. Crystallinities of n-alkanes show a slow decrease trend from C8 to C20. When the carbon number n-alkanes are heavier than C20, the crystallinities of n-alkanes begin to sharply reduce with an increase of carbon number. The largest decline of crystallinity is C26 n-alkane from 38.39% to 7.90%.
Co-reporter:Yilin Li, Zhipeng Li, Tursunjan Ablekim, Tianhui Ren and Wen-Ji Dong
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 47) pp:NaN26202-26202
Publication Date(Web):2014/11/03
DOI:10.1039/C4CP03521F
A rational design strategy of novel fluorophores for luminescent down-shifting (LDS) application was proposed and tested in this paper. Three new fluorophores (1a–c) with specific intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) characteristics were synthesized as LDS molecules for increasing the output short circuit current density (Jsc) of a CdTe solar cell. Photophysical studies of their solution and solid states, and photovoltaic measurements of their PMMA solid films applied on a CdTe solar cell suggested that the specific spectroscopic properties and Jsc enhancement effects of these molecules were highly related to their chemical structures. The Jsc enhancement effects of these fluorophores were measured on both a CdTe small cell and a large panel. An increase in the output Jsc by as high as 5.69% for a small cell and 8.88% for a large panel was observed. Compared to a traditional LDS molecule, Y083, these fluorophores exhibited more superior capabilities of LDS.
![Propanedinitrile, 2-[[4-(1,2,2-triphenylethenyl)phenyl]methylene]-](/data/chemimg/139000/1453863-71-2.png)
![Propanedinitrile, 2-[[4-(1,2,2-triphenylethenyl)phenyl]methylene]-](/data/chemimg/139000/1453863-71-2_b.png)
