Considering the increasing demand for wearresistant materials used for various frictions with dynamic sealing parts,we employed hybrid magnetron sputtering technology to fabricate Cr/amorphous carbon(a-C)multilayered ...Considering the increasing demand for wearresistant materials used for various frictions with dynamic sealing parts,we employed hybrid magnetron sputtering technology to fabricate Cr/amorphous carbon(a-C)multilayered coatings with and without Cr doping for comparison.The tribological behaviors of coatings paired with polyether ether ketone(PEEK)balls were investigated under different friction environments,including an evolving atmosphere,a NaCl solution,polyalphaolefin(PAO)oil,and water-in-oil(W/O).The results demonstrated that the tribological properties of all friction pairs were strongly influenced by the surrounding environment.In the atmosphere and in a NaCl solution,the addition of Cr promoted the formation of a-C-containing transfer films,thereby yielding stable and low friction characteristics.However,the dominant factor contributing to the tribological performance shifted from the coatings themselves to the PAO oil film with PAO medium.In the case of the W/O solution,both the facile reactivity of Cr and the intrinsic instability of the W/O mixture accelerated the presence of Cr_(2)O_(3),which caused more severe wear.The current observations not only identified the tribological failure mechanism of Cr/a-C coatings with and without Cr doping modifications in conjunction with their PEEK counterparts but also addressed the importance of designing and fabricating adaptive lubricant coatings for harsh multi-environment applications.展开更多
Ionic liquids have been widely discussed as potential lubricants,however,their properties make them also very good potential candidates as lubricant additives(e.g.,friction modifiers and anti-wear).In this work,the tr...Ionic liquids have been widely discussed as potential lubricants,however,their properties make them also very good potential candidates as lubricant additives(e.g.,friction modifiers and anti-wear).In this work,the tribological study of two ionic liquids(tributylmethylphosphonium dimethylphosphate(PP),and 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate(BMP))as lubricant additives has been performed on stainless steel(AISI 316L)exposed to polar(water-glycol)and non-polar(polyalphaolefin)based lubricants under boundary lubricating conditions.The performance of these ionic liquids as lubricant additives has been compared to a classical organic friction modifier(dodecanoic acid(C12)).The water–glycol lubricant formulated with the two ionic liquids showed friction values higher than the same base lubricant formulated with dodecanoic acid,however,opposite results were observed for polyalphaolefin(PAO).A detailed surface chemical analysis using X-ray photoelectron spectroscopy(XPS)revealed differences in the passive/tribofilm thickness and chemical composition of the stainless steel surface tested in all lubricants.In the case of the polar lubricant additivated with ionic liquids,the tribochemical reaction accompanied by a tribocorrosion process led to the formation of an unstable passive/tribofilm resulting in high friction and wear.However,in the absence of tribocorrosion process(polyalphaolefin base lubricant),the tribochemical reaction led to the formation of a stable passive/tribofilm resulting in low friction and wear.A detailed surface and subsurface investigation of the microstructure using scanning electron microscopy equipped with a focused ion beam(SEM-FIB)showed that high wear rates resulted in thicker recrystallization region under the wear track surface.Among all lubricant additives tested in this work,BMP in non-polar lubricant media showed the best tribological performance.展开更多
基金financially supported by the National Key R&D Program of China(2022YFC2805701)the National Natural Science Foundation of China(52025014 and U20A20296)+1 种基金Zhejiang Lingyan Research and Development Program(2024C01159)Major Special Project of Ningbo(2023Z198).
文摘Considering the increasing demand for wearresistant materials used for various frictions with dynamic sealing parts,we employed hybrid magnetron sputtering technology to fabricate Cr/amorphous carbon(a-C)multilayered coatings with and without Cr doping for comparison.The tribological behaviors of coatings paired with polyether ether ketone(PEEK)balls were investigated under different friction environments,including an evolving atmosphere,a NaCl solution,polyalphaolefin(PAO)oil,and water-in-oil(W/O).The results demonstrated that the tribological properties of all friction pairs were strongly influenced by the surrounding environment.In the atmosphere and in a NaCl solution,the addition of Cr promoted the formation of a-C-containing transfer films,thereby yielding stable and low friction characteristics.However,the dominant factor contributing to the tribological performance shifted from the coatings themselves to the PAO oil film with PAO medium.In the case of the W/O solution,both the facile reactivity of Cr and the intrinsic instability of the W/O mixture accelerated the presence of Cr_(2)O_(3),which caused more severe wear.The current observations not only identified the tribological failure mechanism of Cr/a-C coatings with and without Cr doping modifications in conjunction with their PEEK counterparts but also addressed the importance of designing and fabricating adaptive lubricant coatings for harsh multi-environment applications.
基金The authors would like to acknowledge the financial support from Indonesia Endowment Fund for Education(LPDP),M-ERANET GreenCOAT project with Project Number 4153,and the Norwegian Microand Nano-fabrication facility,NorFab,for providing the characterization facilities.
文摘Ionic liquids have been widely discussed as potential lubricants,however,their properties make them also very good potential candidates as lubricant additives(e.g.,friction modifiers and anti-wear).In this work,the tribological study of two ionic liquids(tributylmethylphosphonium dimethylphosphate(PP),and 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate(BMP))as lubricant additives has been performed on stainless steel(AISI 316L)exposed to polar(water-glycol)and non-polar(polyalphaolefin)based lubricants under boundary lubricating conditions.The performance of these ionic liquids as lubricant additives has been compared to a classical organic friction modifier(dodecanoic acid(C12)).The water–glycol lubricant formulated with the two ionic liquids showed friction values higher than the same base lubricant formulated with dodecanoic acid,however,opposite results were observed for polyalphaolefin(PAO).A detailed surface chemical analysis using X-ray photoelectron spectroscopy(XPS)revealed differences in the passive/tribofilm thickness and chemical composition of the stainless steel surface tested in all lubricants.In the case of the polar lubricant additivated with ionic liquids,the tribochemical reaction accompanied by a tribocorrosion process led to the formation of an unstable passive/tribofilm resulting in high friction and wear.However,in the absence of tribocorrosion process(polyalphaolefin base lubricant),the tribochemical reaction led to the formation of a stable passive/tribofilm resulting in low friction and wear.A detailed surface and subsurface investigation of the microstructure using scanning electron microscopy equipped with a focused ion beam(SEM-FIB)showed that high wear rates resulted in thicker recrystallization region under the wear track surface.Among all lubricant additives tested in this work,BMP in non-polar lubricant media showed the best tribological performance.
