Study On Tribological Behavior For PVD Coatings Prepared By Magnetron Sputtering

With the rapid development of modern manufacturing industry,the demand for material processing is becoming higher and higher.For example,a tool is required to cut materials at high speed and high temperatures.Under the extreme conditions of high temperature and high speed,tool wear speed is accelerated,which will hinder the effective development of national economy.Therefore,the tool of high temperature wear-resistant protection technology has become one of the key issues in the manufacturing industry.The traditional protection method is to coat the tool surface with a layer of lubricating oil,which can quickly reduce the friction coefficient.But the wear resistance of the tool will decrease sharply.At the same time,the volatilization of lubricating oil at high temperature will also bring a series of environmental pollution problems,which is not in line with the green and sustainable development policy.The modern common protection technology is a layer of coating on the surface of the tool,in which the transition metal nitride（TMN）coating technology is more mature.From the composition and structure of the two aspects of optimization,play a high-temperature wear-resistant comprehensive effect.About the composition:the oxidation product of tungsten（W）is tungsten oxide（WO₃）with self-lubricating effect,which can reduce friction at high temperature or during the friction process.The silicon（Si）and nitrogen（N）components combine to form the amorphous phase of Si₃N₄,which has good oxidation resistance and ensures the coating structure to maintain stability and delay oxidation at high temperature.About the structure:nanocomposite structure has the advantages of high density,low surface roughness,good mechanical properties,etc.,its special structural characteristics can improve the wear resistance of the coating,and to a certain extent improve the anti-oxidation performance.Generally,increasing Si doping can effectively improve the oxidation resistance and wear resistance of the coating.However,with the increase of Si content,the wear resistance will decrease with the change of wear body.Therefore,optimizing the high-temperature wear-resistant coating is not to blindly improve the content of Si components,but to comprehensively consider the antioxidant and wear-resistant properties.Therefore,it is of great significance to find the key component points of Si content.In this paper,magnetron sputtering technology was used to prepare WSiN coatings with different Si contents and structures by changing the Si target power,and the influence of Si content and structure on the wear resistance and oxidation resistance of the coatings was systematically studied.The main conclusions are as follows:（1）On the basis of composition,0 at.%Si,2.4 at.%Si,6.8 at.%Si,10.5 at.%Si,18.2 at.%Si.The W₂N coating with low Si content and 2.4 at.%Si WSiN coating have good wear resistance at room temperature,poor oxidation resistance and high temperature wear resistance.The high Si content 18.2 at.%Si coating has poor wear resistance at room temperature,but shows good oxidation resistance and high temperature wear resistance.（2）On the basis of structure,the wear resistance and oxidation resistance of the dense W₂N coating at room temperature are better than 6.8 at.%Si coating.High degree amorphous phase coated nanocrystalline structure has the best wear resistance at high temperature.Therefore,high density coating can improve the wear resistance at room temperature,and a certain degree of oxidation resistance,but high encapsulation degree of amorphous coating nanostructure is more important to improve the wear resistance at high temperature.