Production and Tribological Investigation of Cr Borides by Boriding of Powder Metallurgy Pure Chromium Surface

Abstract

Borides are considered advanced building materials due to their high melting temperature, hardness, wear/corrosion/oxidation resistance and excellent thermal and electrical properties. Among the many metal borides, chromium borides are known for their high electrical conductivity and high hardness. In this study, it is aimed to form CrxBx on powder metal pure Cr material and to examine its wear characteristics. For the production of samples, commercial purity Cr powders were mixed for 60 min and pressed under 850 MPa pressure to obtain raw samples. After pressing, the samples were boronized at 1000 ºC for 2, 4, 6 and 8 h, and a hard boride layer was formed on the outer surface. Hardness, abrasion tests and then then Field Emission Scanning Electron Microscopy, energy-dispersive x-ray spectroscopy and x-ray diffraction analyzes were applied to the samples obtained. It was determined that CrB, Cr2B, Cr2B3and Cr3B4 borides were formed on the surface with boronizing process and the hardness of these phases increased significantly. The wear resistance of P/M Cr specimens could also be improved by increasing the hardness. © 2022, ASM International.