Influence Of Ag Contents On Microstructure,Mechanical And Tribological Properties Of ZrN Based Nanocomposite Films

In this paper,a series of ZrAlN-Ag,ZrMgN-Ag and ZrSiN-Ag composite films with different Ag content were prepared at room temperature by multi-target magnetron sputtering technique.The chemical components,microstructures,microhardness,tribological properties were measured by EDS,XRD,SEM,Raman spectrometry,nano-indentation,ball-on-disc tribo-meter and 3D profilometer.The results are as follows:The research of ZrAlN-Ag composite films showed that fcc-ZrAlN,fcc-Ag and h-Al N co-existed in ZrAlN-Ag films.With the increase of Ag content,the hardness and elastic modulus of ZrAlN-Ag film increased first and then decreased.After doping 0.41 at.%Ag,the hardness and elastic modulus reached a maximum value of 26.2 GPa and 336.5 GPa.At room temperature,with the increase of Ag content,the friction coefficient of ZrAlN-Ag composite films decreased gradually,and the wear rate decreased first and then increased.When the test temperature rised from 200 to 600°C,the friction coefficient decreased first and then increased,and the wear rate continues to increase.The research of ZrMgN-Ag composite films showed that fcc-ZrN,fcc-Ag and h-Mg co-existed in ZrMgN-Ag films.When Ag content was higher than 7.03 at.%,the preferential orientation of fcc-ZrN changed from(111)to(200).With the increase of Ag content,the hardness and elastic modulus of ZrMgN-Ag film increased first and then decreased.After doping 0.55 at.%Ag,the hardness and elastic modulus reached a maximum value of 25.8GPa and 323.5 GPa.At room temperature,with the increase of Ag content,the friction coefficient of Zr Mg N-Ag composite films then decreased gradually,the wear rate decreased first and then increased.After doping12.33 at.%Ag,when the test temperature rised from200 to 500°C,the friction coefficient decreased gradually.At 500°C,the friction coefficient reached a lowest value of 0.28.This was mainly attributed to the existence of AgO_x,ZrO_xlubrication phase that acted as solid lubricant to modify wear mechanism.The research of ZrSiN-Ag composite films showed that fcc-ZrN and fcc-Ag co-existed in ZrSiN-Ag films.With the increase of Ag content,the hardness and elastic modulus of ZrSiN-Ag films increased first and then decreased,After doping 0.46 at.%Ag,the hardness and elastic modulus reached a maximum value of 27.6 GPa and 311.2 GPa.At room temperature,with the increase of Ag content,the friction coefficient of ZrSiN-Ag composite film decreased gradually,the wear rate first decreased and then increased.As the temperature increased to 700°C,the friction coefficient of ZrSiN-Ag(25.36 at.%)composite films decreased first and then increased,and the minimum value of the friction coefficient was 0.33 at 500°C.The wear rate increased gradually with the increased of temperature.As a result,it indicated that the addition of Ag to the films can improve the friction performance of the film at low and medium temperature,but there is no obvious improvement effect at high temperature,and it cannot improve the wear performance.The reduction of friction coefficient is related to AgO_xand ZrO_x.