Effect of a hard supra-thick interlayer on adhesion of DLC film prepared with PBIID process

Abstract

Diamond-like carbon (DLC) films were prepared on aluminum alloy (A5052) and tungsten-carbide (WC) substrates with plasma-based ion implantation and deposition (PBIID) using hydrocarbon gas. Adhesion strength of DLC film was increased by the formation of interfacial mixing layer by carbon ion implantation and the production of SiCx nanolayer on the substrate prior to DLC deposition. As DLC films on the softer substrate were broken easily because of large deformation of substrate by local loads, the hard and supra-thick interlayer of plasma-sprayed tungsten-carbide (WC) with the thickness of 100–200μm was produced to protect the softer substrate between the DLC film and the substrate. The scratch testing evaluation showed that the supra-thick WC interlayer improved remarkably the adhesion of DLC films on the aluminum alloy substrate and the thicker WC interlayer was more effective for improvement of adhesion.