Cailiao Baohu (Aug 2023)
Study on Structure and High Temperature Tribological Properties of VAlTiCrM(M=Mo，W，and Si) High-Entropy Alloy Coatings
Abstract
Motion devices in high temperature environments suffer serious friction and wear damage，which puts forward strict requirements for their surface protective coatings.High-entropy alloys have good composition design flexibility and excellent comprehensive properties.Low friction and high wear resistant coatings can be obtained through composition regulation，thereby achieving efficient protection of high temperature service components.In order to obtain low friction and wear resistant protective coatings for moving parts servicing in high temperatures in this paper，VAlTiCr-based high-entropy alloy coatings were prepared by magnetron sputtering.The effects of different elements (Mo，W，and Si) and heat treatment temperatures (700，800，and 900 ℃) on the crystal structure and high temperature friction properties of high-entropy alloy coatings were studied.Results showed that the as-prepared VAlTiCrSi coating was amorphous，while the VAlTiCrMo and VAlTiCrW coatings exhibited BCC solid solution structure.The tribological properties of the coatings after heat treatment were tested at 700 ℃，which showed that with the increase of heat treatment temperature，the friction coefficient and wear rate of the three coatings decreased first and then increased；And after heat treatment at 800 ℃，VAlTiCrMo，VAlTiCrW and VAlTiCrSi coatings all had the best tribological properties.Oxides such as V2O5 and AlVO4 played a major role in lubrication.VAlTiCrMo coating has better comprehensive friction performance than VAlTiCrSi and VAlTiCrW coatings.The friction coefficient was as low as 0.21，and the wear rate was only 9.98×10-5mm3/(N·m).Therefore，the element regulation and heat treatment of high-entropy alloy coating could provide data reference for the research of the high-performance protective coating serving in harsh environments.
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