The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated tempera...The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated temperatures,has hindered the widespread use of these materials in industrial applications.This paper took this challenge to break through the above established relationship by developing novel nacrelike multilayered Mo_(2)N–SiN_(x)/Ag–SiN_(x)self-lubricant films via an radio frequency(RF)magnetron sputtering system for real applications where harsh conditions at elevated temperatures exist.The multilayered films,deposited by alternating deposition of Mo_(2)N–SiN_(x)and Ag–SiN_(x)modulation layers,exhibited three phases of face-centered cubic(fcc)Mo_(2)N,fcc Ag and SiN_(x),where SiN_(x)encapsulated the nano-crystalline Mo_(2)N and Ag phases in each layer to successfully induce a“brick and mortar”nacre-like microstructure(in the area without the coherent structure).The epitaxy growth of the Ag–SiN_(x)layers with thickness below 6 nm on the Mo_(2)N template resulted in an extraordinary increase in both the hardness and elastic modulus,which was able to prevent severe degradation of the mechanical properties caused by the addition of Ag.The room-temperature anti-friction property could be enhanced by increasing the Ag–SiN_(x)layer thickness due to the excellent lubricant nature of Ag,which acts in synergy with Mo_(2)N,while the wear rate below 4×10^(−8)mm^(3)/(N·mm)was due to the high mechanical strength.The tribological properties at 600℃also benefited from the interlocked multilayered architecture,which allowed an extreme low friction coefficient of~0.12 and a negligible wear rate(WR).This behavior was attributed to the synergism between the lubricant action of Ag and Mo_(2)N and the tribo-phase transformation from Ag_(2)Mo_(4)O_(13)to Ag_(2)MoO_(4).展开更多
A multilayer film,composed by ZrN‒Ag(20 nm)and Mo‒S‒N(10 nm)layers,combining the intrinsic lubricant characteristics of each layer was deposited using DC magnetron sputtering system,to promote lubrication in a wide-ra...A multilayer film,composed by ZrN‒Ag(20 nm)and Mo‒S‒N(10 nm)layers,combining the intrinsic lubricant characteristics of each layer was deposited using DC magnetron sputtering system,to promote lubrication in a wide-range of temperatures.The results showed that the ZrN‒Ag/Mo‒S‒N multilayer film exhibited a sharp interface between the different layers.A face-centered cubic(fcc)dual-phases of ZrN and Ag co-existed in the ZrN‒Ag layers,whilst the Mo‒S‒N layers displayed a mixture of hexagonal close-packed MoS_(2)(hcp-MoS_(2))nano-particles and an amorphous phase.The multilayer film exhibited excellent room temperature(RT)triblogical behavior,as compared to the individual monolayer film,due to the combination of a relative high hardness with the low friction properties of both layers.The reorientation of MoS_(2)parallel to the sliding direction also contributed to the enhanced anti-frictional performance at RT.At 400℃,the reorientation of MoS_(2)as well as the formation of MoO_(3)phase were responsible for the lubrication,whilst the hard t-ZrO_(2)phase promoted abrasion and,consequently,led to increasing wear rate.At 600℃,the Ag_(2)MoO_(4)double-metal oxide was the responsible for the low friction and wear-resistance;furthermore,the observed transformation from t-ZrO_(2)to m-ZrO_(2),could also have contributed to the better tribological performance.展开更多
基金supported by projects granted by the National Natural Science Foundation of China(Nos.52171071 and 51801081)national funds through FCT of Portugal-Fundação para a Ciência e a Tecnologia,under a scientific contract of 2021.04115.CEECIND,2023.06224.CEECIND+3 种基金the projects of UIDB/00285/2020,and LA/0112/2020,MCTool21-ref.“POCI-01-0247-FEDER-045940”co-financed via FEDER and FCTFundação para a Ciência e a Tecnologia(COMPETE)The projects of UIDB/00285/2020,and LA/0112/2020The Slovenian Research Agency ARIS under the Research Core Funding Programme No.P2-0231 and the project MSCA-COFUND-5100-237/2023-9supported by the Outstanding University Young Teachers of“Qing Lan Project”of Jiangsu Province of China and the Excellent Talents of“Shenlan Project”of Jiangsu University of Science of China.
文摘The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated temperatures,has hindered the widespread use of these materials in industrial applications.This paper took this challenge to break through the above established relationship by developing novel nacrelike multilayered Mo_(2)N–SiN_(x)/Ag–SiN_(x)self-lubricant films via an radio frequency(RF)magnetron sputtering system for real applications where harsh conditions at elevated temperatures exist.The multilayered films,deposited by alternating deposition of Mo_(2)N–SiN_(x)and Ag–SiN_(x)modulation layers,exhibited three phases of face-centered cubic(fcc)Mo_(2)N,fcc Ag and SiN_(x),where SiN_(x)encapsulated the nano-crystalline Mo_(2)N and Ag phases in each layer to successfully induce a“brick and mortar”nacre-like microstructure(in the area without the coherent structure).The epitaxy growth of the Ag–SiN_(x)layers with thickness below 6 nm on the Mo_(2)N template resulted in an extraordinary increase in both the hardness and elastic modulus,which was able to prevent severe degradation of the mechanical properties caused by the addition of Ag.The room-temperature anti-friction property could be enhanced by increasing the Ag–SiN_(x)layer thickness due to the excellent lubricant nature of Ag,which acts in synergy with Mo_(2)N,while the wear rate below 4×10^(−8)mm^(3)/(N·mm)was due to the high mechanical strength.The tribological properties at 600℃also benefited from the interlocked multilayered architecture,which allowed an extreme low friction coefficient of~0.12 and a negligible wear rate(WR).This behavior was attributed to the synergism between the lubricant action of Ag and Mo_(2)N and the tribo-phase transformation from Ag_(2)Mo_(4)O_(13)to Ag_(2)MoO_(4).
基金supported by the National Natural Science Foundation of China(Nos.52171071,51801081,and 52071159)national funds through FCT of Portugal-Fundação para a Ciência e a Tecnologia,under a scientific contract of 2021.04115.CEECIND,and the project of UIDB/00285/2020,LA/0112/2020,MCTool21-ref.“POCI-01-0247-FEDER-045940”cofinanced via FEDER and FCT-Fundação para a Ciência e a Tecnologia(COMPETE),Outstanding University Young Teachers of“Qing Lan Project”of Jiangsu Province of China,Excellent Talents of“Shenlan Project”of Jiangsu University of Science of China.
文摘A multilayer film,composed by ZrN‒Ag(20 nm)and Mo‒S‒N(10 nm)layers,combining the intrinsic lubricant characteristics of each layer was deposited using DC magnetron sputtering system,to promote lubrication in a wide-range of temperatures.The results showed that the ZrN‒Ag/Mo‒S‒N multilayer film exhibited a sharp interface between the different layers.A face-centered cubic(fcc)dual-phases of ZrN and Ag co-existed in the ZrN‒Ag layers,whilst the Mo‒S‒N layers displayed a mixture of hexagonal close-packed MoS_(2)(hcp-MoS_(2))nano-particles and an amorphous phase.The multilayer film exhibited excellent room temperature(RT)triblogical behavior,as compared to the individual monolayer film,due to the combination of a relative high hardness with the low friction properties of both layers.The reorientation of MoS_(2)parallel to the sliding direction also contributed to the enhanced anti-frictional performance at RT.At 400℃,the reorientation of MoS_(2)as well as the formation of MoO_(3)phase were responsible for the lubrication,whilst the hard t-ZrO_(2)phase promoted abrasion and,consequently,led to increasing wear rate.At 600℃,the Ag_(2)MoO_(4)double-metal oxide was the responsible for the low friction and wear-resistance;furthermore,the observed transformation from t-ZrO_(2)to m-ZrO_(2),could also have contributed to the better tribological performance.
