High stability and high corrosion resistance of a class of Co–Cr–Mo–Nb–B high-entropy metallic glasses

Abstract

In this study, we have developed a class of new Co–Cr–Mo–Nb–B high-entropy metallic glass alloys with high stability and high corrosion resistance. It was found that for Co26Cr26Mo26Nb7B15 metallic glass, the glass transition temperature reached to 1058 K, and the initial crystallization temperature of Co24.5Cr26.5Mo26.5Nb7.5B15 metallic glass was as high as 1132 K. There is a large hardness of 18.1 GPa and Young's modulus of 267 GPa of Co27.5Cr27.5Mo26.5Nb3.5B15 metallic glass. The excellent thermodynamic property and mechanical properties were proved to be related to the covalence bond and hybridization of metal-metalloid bonds. The Co–Cr–Mo–Nb–B metallic glasses exhibited a lower self-corrosion current density and higher self-corrosion voltage compared with 316 in 1 M hydrochloric acid solution, and the high corrosion resistance could be attributed to passive films enriched with Cr3+ and Mo4+. These findings provide a new and effective way to design high-entropy metallic glasses with excellent comprehensive properties and suitable for high stability applications.