Study On The Tribological Properties Of AlCoCrCuFeNi High-entropy Alloy In Hydrogen Peroxide

Based on the problem of sliding friction pair used in high-test hydrogen peroxide (HTP) involved in the subproject "Friction and Wear Behaviours of New Metallic Materials under the Effect of Strong Oxidants" originated from the national 973 project "Tribological Properties of Materials under the Effect of Strong Oxidants", tribology, morphology, spectroscopy and other means were employed to study the tribological properties, the friction behaviours and wear mechanisms of AlCoCrCuFeNi high-entropy alloy in HTP which was a newly developed structural material. Besides, the interaction and correlation among tribological properties, material structure, heat treatment and other aspects was discussed. The whole work was aimed at providing a theoretical and experimental basis for the development of seeking new friction materials under strong oxidants and for expanding the application of high-entropy alloys in the future. The main contents and results of this study could be summarized as follows.(1) The tribotest results of as-cast AlCoCrCuFeNi alloy and 1Cr18Ni9Ti stainless steel sliding against engineering ceramics in HTP with concentration of 90% showed that, AlCoCrCuFeNi alloy pairing with SiC and SisN4 ceramics had better tribological performance than 1Cr18Ni9Ti stainless steel. When pairing with Si3N4 ceramic, AlCoCrCuFeNi alloy displayed significant tribological performance.(2) In HTP with concentration of 90%, the main wear mechanism of AlCoCrCuFeNi/ZrO2 pair was a mixture of adhesive wear, abrasive wear and oxide wear, while both AlCoCrCuFeNi/SiC pair and AlCoCrCuFeNi/Si3N4 pair performed polishing oxide wear. In addition, AlCoCrCuFeNi/Si3N4 pair had the effect of boundary lubrication which led to small and smooth friction coefficient and tiny wear of AlCoCrCuFeNi alloy.(3) After tempering from 600℃,645℃,700℃and 1000℃, the tribological properties of as-cast AlCoCrCuFeNi high-entropy alloy pairing with Si3N4 ceramic in HTP with concentration of 90% had obvious changes. With the increase of tempering temperature of as-cast AlCoCrCuFeNi, the initial friction coefficient and run-in time of AlCoCrFeNiCu/Si3N4 increased, the average friction coefficient of run-in period and stable period both increased, and AlCoCrCuFeNi alloy had larger wear.(4) Tempering AlCoCrCuFeNi alloy kept the dendrite and interdendritic phase structure found in as-cast AlCoCrCuFeNi alloy. With the increase of tempering temperature, the segregation of Cu element in dendrite region increased which led to the decrease of the content of BCC structure and hardness of dendrite region.