A new interlayer approach for CVD diamond coating of steel substrates

Abstract

A Ni/Cu/Ti multilayer system is proposed to face the typical problems-related with direct diamond deposition on steel substrates, namely the lack of adhesion and growth rates. Systematic experimental work allowed achieving the best MPCVD parameter set in order to obtain both thin and thick diamond films (5-130 mum) with good morphology and adhesion with low residual stress level. In fact, a thick soft copper layer permits to accommodate the thermally-induced stresses during the cooling stage of MPCVD process, allowing good diamond film integrity. The films thus obtained are continuous and uniform, crack-free and well adhered as required in most mechanical applications. The characterization techniques were: Scanning electron microscopy (SEM) to observe morphology; mu-Raman spectroscopy to check diamond film quality and stress state evaluation; X-ray diffraction to measure the residual stresses; micro-indentation to examine the diamond film adherence; profilometry to measure the surface roughness. (C) 2003 Elsevier B.V. All rights reserved.