Carbon-based solid lubricants are excellent options to reduce friction and wear,especially with the carbon capability to adopt different allotropes forms.On the macroscale,these materials are sheared on the contact al...Carbon-based solid lubricants are excellent options to reduce friction and wear,especially with the carbon capability to adopt different allotropes forms.On the macroscale,these materials are sheared on the contact along with debris and contaminants to form tribolayers that govern the tribosystem performance.Using a recently developed advanced Raman analysis on the tribolayers,it was possible to quantify the contactinduced defects in the crystalline structure of a wide range of allotropes of carbon-based solid lubricants,from graphite and carbide-derived carbon particles to multi-layer graphene and carbon nanotubes.In addition,these materials were tested under various dry sliding conditions,with different geometries,topographies,and solid-lubricant application strategies.Regardless of the initial tribosystem conditions and allotrope level of atomic ordering,there is a remarkable trend of increasing the point and line defects density until a specific saturation limit in the same order of magnitude for all the materials tested.展开更多
Polyether ether ketone(PEEK)is a high-performance thermoplastic,which is often selected for high-temperature tribological applications under chemically aggressive environments.The present work investigates the tribolo...Polyether ether ketone(PEEK)is a high-performance thermoplastic,which is often selected for high-temperature tribological applications under chemically aggressive environments.The present work investigates the tribological behavior of a high-performance PEEK composite under conditions that are often found inside hermetic compressors.Therefore,an AMTI tribometer equipped with a hermetic chamber and a heating system was used to conduct sliding tests of PEEK cylinders on AISI 304 stainless steel polished discs(S_(q)<10 nm)with reciprocating movement and a normal force of 175 N.The tribological behavior of the PEEK/AISI 304 stainless steel system was investigated as a function of ambient temperature(30℃ and 80℃)and atmosphere(atmospheric air and tetrafluoroethane).Wear and surface roughness analyses were performed with white light interferometry and optical microscopy.Raman spectroscopy was used to investigate transfer films on the counter body surface.Temperature was observed to have a strong influence on the tribological behavior of the samples tested under atmospheric air,with a 25%decrease in the friction coefficient associated with a 100%increase in the wear rate.However,the friction measured from the samples tested under a tetrafluoroethane atmosphere showed no significant temperature dependence.展开更多
基金the following Brazilian agencies for funding this research:CNPq,CAPES,BNDES and the Chilean agency ANID Vinculación Internacional FOVI220096(No.72190023)as well as Nidec Global Appliance/Embraco.
文摘Carbon-based solid lubricants are excellent options to reduce friction and wear,especially with the carbon capability to adopt different allotropes forms.On the macroscale,these materials are sheared on the contact along with debris and contaminants to form tribolayers that govern the tribosystem performance.Using a recently developed advanced Raman analysis on the tribolayers,it was possible to quantify the contactinduced defects in the crystalline structure of a wide range of allotropes of carbon-based solid lubricants,from graphite and carbide-derived carbon particles to multi-layer graphene and carbon nanotubes.In addition,these materials were tested under various dry sliding conditions,with different geometries,topographies,and solid-lubricant application strategies.Regardless of the initial tribosystem conditions and allotrope level of atomic ordering,there is a remarkable trend of increasing the point and line defects density until a specific saturation limit in the same order of magnitude for all the materials tested.
文摘Polyether ether ketone(PEEK)is a high-performance thermoplastic,which is often selected for high-temperature tribological applications under chemically aggressive environments.The present work investigates the tribological behavior of a high-performance PEEK composite under conditions that are often found inside hermetic compressors.Therefore,an AMTI tribometer equipped with a hermetic chamber and a heating system was used to conduct sliding tests of PEEK cylinders on AISI 304 stainless steel polished discs(S_(q)<10 nm)with reciprocating movement and a normal force of 175 N.The tribological behavior of the PEEK/AISI 304 stainless steel system was investigated as a function of ambient temperature(30℃ and 80℃)and atmosphere(atmospheric air and tetrafluoroethane).Wear and surface roughness analyses were performed with white light interferometry and optical microscopy.Raman spectroscopy was used to investigate transfer films on the counter body surface.Temperature was observed to have a strong influence on the tribological behavior of the samples tested under atmospheric air,with a 25%decrease in the friction coefficient associated with a 100%increase in the wear rate.However,the friction measured from the samples tested under a tetrafluoroethane atmosphere showed no significant temperature dependence.
