| According to the development trend of modern mechanical processing,a great number of highly intelligent automation equipment has been put into production,and the machining process has become high-speed and efficient.The harsh working conditions such as high temperature,high speed,heavy load,and corrosion have become a practical problem that various materials cannot be avoided.In order to enhance the service life of materials such as mechanical parts,the research significance of surface coating technology is particularly significant.It can not only maintain the properties of the material itself,but also improve the coating surface properties to extend the service life.After decades of development,there are also endless ways to prepare coatings.Among them,Physical Vapor Deposition(PVD)is the most representative.However,the traditional PVD has a large number of technical defects and it is difficult to meet the needs of the industry.At the same time,the emerging High Power Impulse Magnetron Sputtering(HIPIMS)deposition rate is too low to adapt to industrial mass production.Therefore,in this paper,starting from increasing the deposition rate of HIPIMS,Cr/CrN and CrAl/CrAl N coatings were prepared by co-sputtering using HIPIMS and Bipolar Pulse Magnetron Sputtering.The same coating was prepared by arc ion evaporation plating(AIP)which widely used in the market as a control group.The morphology,composition and phase of the coatings were characterized,and the electrochemical corrosion performance,friction performance,and high temperature oxidation performance of the coatings were analyzed.The main results obtained are as follows:1.After parameter setting,the deposition rate of Cr/CrN coatings prepared by Hybrid HIPIMS can reach 37.63 nm/min,and the deposition rate of CrAl/CrAl N coatings can reach 36.67 nm/min,which reaches or exceeds the deposition rate of AIP.2.The Cr/CrN and CrAl/CrAlN coatings prepared by the Hybrid HIPIMS have a dense structure,a uniform surface morphology and few defects,resulting in low surface roughness.These structural differences lead to a small surface friction coefficient of Cr/CrN and CrAl/CrAl N coatings prepared by Hybrid HIPIMS,and at the meanwhile,corrosion holes are difficult to form on the surface,and the corrosion resistance is better than that of AIP coatings which with obvious surface defects.3.With the increase of the Cr/CrN,CrAl/CrAlN double-layer film cycle,the grains of the coating structure can be refined,the coating quality can be improved and the compactness of the coating structure can be increased.In addition,the surface roughness of the coating is reduced,the resistance to electrochemical corrosion is enhanced and the friction coefficient of the coating surface is reduced.4.At 800?,the diffusion depth of oxygen in the coating prepared by AIP is 2.5?m,and in the coating prepared by Hybrid HIPIMS is about 1.5?m.At the same time,in the high temperature oxidation test of the CrAl/CrAl N coating,21.4 at%nitrogen still exists inside the coating at 1100?,and the surface is covered by a dense oxide film,which shows excellent thermal stability.This shows that the coating prepared by composite HIPIMS has a higher temperature oxidation resistance than the coating prepared by AIP.5.The electrochemical corrosion behavior of the coatings after oxidation at different temperatures was investigated.It was found that with the increase of the oxidation temperature,the electrochemical corrosion resistance of the coatings deposited by AIP and Hybrid HIPIMS gradually increased during the kinetic potential polarization curve test,and after oxidation at 800°C the self-corrosion current density of the Cr/CrN coating prepared by Hybrid HIPIMS is only 2.4×10-9A·cm-2,which obtained the strongest corrosion resistance of all coatings introduced in this paper. |
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