Tribological Behavior of a Hard TiB2/TiC Multilayer Formed on M2 Steel Using a Duplex Process: Cathodic Arc Physical Vapor Deposition and Cathodic Reduction/Thermal Diffusion-Based Boriding

The aim of this paper was to investigate the tribological behavior of a hard TiB2/TiC multilayerTiB2/TiC multilayer on M2 high-speed steelHigh-speed steel (M2 HSSM2 HSS). The mentioned multilayer was formed using a combined processProcessincluding cathodic arc-physical vapor depositionCathodic Arc-Physical Vapor Deposition (CA-PVD)(CA-PVD) and cathodic reduction/thermal diffusion-based boridingCathodic reduction/thermal diffusion-based boriding (CRTD-Bor) (CRTD-Bor), which is a fast, cost-effective, and environmentally friendly method. In this regard, the CRTD-Bor processProcess was applied on CA-PVD Ti-deposited M2 steelSteel. During boriding, the upper portion of the TiTitaniumcoatingCoatingdeposited on HSSHigh-speed steel underwent conversion into TiTitanium borides, while, a TiC layer was simultaneously formed at the bottom of the coatingCoating layer interface between the TiTitanium deposit and the steelSteel matrix. The hardnessHardness value of the produced TiB2 layer measured by micro-indentation was 41 ± 5 GPa with a good adhesion strength (HF1) to the substrate. Also, the tribological investigationTribological investigation of the produced multilayer, which was conducted using the ball-on-disk wear test against the alumina ball, revealed an eight-fold improvement in the wear behavior of the surface-modifiedModifiedHSSHigh-speed steel compared with the bare HSS.