Effect of hBN and SiC addition on laser assisted processing of ceramic matrix composite coatings

Abstract

To develop TiB2–TiN–SiC and TiB2–TiN–SiC-hBN based ceramic matrix composite coatings with superior mechanical and tribological properties suitable for engineering applications, a high-power CW-laser is used to initiate chemical reactions in precursor powder mixtures (TiO2, SiO2, hBN and graphite) of several compositions preplaced over AISI1025 steel substrates. Here, coatings’ stoichiometric compositions (TiB2–TiN–SiC) fabricated through in-situ synthesis are altered by adding SiC and additional amount hBN in the precursor at variable weight ratios. Presence of variable amount of SiC in TiB2–TiN–SiC and hBN in TiB2–TiN–SiC-hBN composites imparts several microstructural, mechanical and tribological property combinations. In this study, an attempt has been made to experimentally evaluate the optimum range of hBN and SiC additions to obtain highest improvements in lubrication and wear resistance respectively.