Thermodiffused vanadium carbide interface for diamond films on steel and cemented carbides substrates

Abstract

In this work an interface is studied and proposed for chemical vapour deposition (CVD) diamond films on sintered carbides and steel substrates, the most relevant tooling materials for mechanical applications. It consists of a thermoreactive deposited and diffused vanadium carbide layer. This interface presents good characteristics for diamond films deposition: high adherence to substrates, favourable thermal expansion coefficient, high hardness and high mechanical strength. Good quality and adherent diamond films are obtained and its characteristics are evaluated by SEM, X-ray diffraction, Raman spectroscopy and indentation tests. For sintered carbides substrates, typical Raman shift of 4·1 cm −1 is obtained, equivalent to compressive residual stresses of 1·4 GPa applied from the substrate to CVD diamond films through vanadium carbide interlayer. For steel substrates, Raman shift reached 20·1 cm −1 , corresponding to 6·93 GPa compressive stress applied from substrate to diamond films through VC interlayer, evidencing the mechanical strength of the VC diamond film coatings.