Study On Microstructure And Friction And Wear Properties Of ZrN-Ag And ZrN-Si₃N₄-Ag Nanostructured Composite Film

ZrN-based films showed broad application prospects in thermonuclear,high-speed train,aerospace and other fields,but their poor friction properties limit their applications.In order to solve the problem of poor friction properties of ZrN films and excessive consumption of lubricating components at medium and high temperature,a series of ZrN-Ag composite films with different Ag contents were prepared by radio frequency magnetron sputtering.A series of ZrN-Si₃N₄-Ag nanostructure composite films with different Si contents were prepared on the basis of ternary ZrN-Ag thin films.The microstructure,mechanics,high temperature oxidation resistance,friction and wear properties and corrosion resistance of the films were studied by XRD,XPS,SEM,TG,UMT-2 high temperature friction and wear tester,nano-mechanical comprehensive testing system and electrochemical workstation,the results are as follows.The nano-structured composite film ZrN-Ag consists of two phases:fcc-ZrN and fcc-Ag.With the increase of Ag content,the substrate adhesion and hardness of the film increased at first and then decreased.When the Ag content is 1.74 at.%,the hardness of the film was the highest,the highest value was 27.75GPa.The friction coefficient of the film at room temperature decreased with the increase of Ag content,the minimum friction coefficient of the film was 0.4436 when the Ag content is 10.59 at.%,and the wear rate of the film decreased at first and then increased with the increase of Ag content,and the minimum wear rate of the film was 5.33×10^-8mm³N^-1mm^-1 when the Ag content is 1.74at.%.When the Ag content is less than 1.74 at.%,the film showed the best comprehensive friction and wear properties.With the increase of temperature from room temperature to500,the friction coefficient of the film decreased and the wear rate increased with the increase of temperature.The minimum friction coefficient was 0.2385 and the maximum wear rate was 17.3664×10^-8mm³N^-1mm^-1.The film had lower friction coefficient and higher wear rate at medium and high temperature.The nanostructured composite films ZrN-Si₃N₄-Ag consists of three phases:fcc-Zr-Si-N,fcc-Ag and amorphous Si₃N₄.With the increase of Si content,the residual stress of the film decreased.At room temperature,the friction coefficient and wear rate of the film decrease at first and then increase with the increase of Si content.When the Si content is12.54 at.%,the friction coefficient is the lowest,which is 0.343;the minimum wear rate of the film was 4.6376×10^-8mm³N^-1mm^-1 at 14.23 at.%Si content.As the temperature increased from room temperature to 500,the friction coefficient of the film decreased at first and then increased,and the minimum friction coefficient was 0.2516 at 100,and the lowest wear rate was 3.995×10^-8mm³N^-1mm^-1 at 300.Compared with ZrN-Ag film,although the friction coefficient of ZrN-Si₃N₄-Ag composite film increased,the wear rate of ZrN-Si₃N₄-Ag composite film was lower in the cyclic wear test at room temperature-300which showed excellent temperature cyclic friction and wear ability,and the coating did not fail after 3 cycles while ZrN-Ag film failed after 1 cycle.The introduction of Si element improved the oxidation resistance of the film,and the corrosion resistance of the film was also improved with the increase of Si content.