ON THE USE OF Mo/Mo2C GRADIENT INTERLAYERS IN DIAMOND DEPOSITION ONTO CEMENTED CARBIDE SUBSTRATES

Abstract

Molybdenum/molybdenum carbide (Mo/Mo2C) gradient interlayers were prepared via double glow plasma surface alloying (DGPSA) technique onto cemented carbide (WC–Co) substrates for diamond deposition. The morphologies, phase composition and adhesion of the interlayers were investigated, as well as their effect on the subsequent diamond deposition. The results indicated that the Mo/Mo2C gradient interlayer deposited on WC–Co substrate was composed of 4.0-[Formula: see text]m-thick diffusion layer and 2.7-[Formula: see text]m-thick deposition layer. The Mo concentration decreased gradually with the depth direction whereas the Co and W concentrations increased. As a result, the Co binder phase was completely restricted within the substrate by the diffusion layer. The presence of gradient diffusion layer ensured excellent adhesion of the interlayer. Subsequently, nanocrystalline diamond coatings with excellent adhesion were deposited on the interlayered substrates. Thus, the Mo/Mo2C gradient interlayers deposited via DGPSA technique were demonstrated as a novel option for depositing adherent diamond coatings on WC–Co substrates.