Structure and mechanical properties of low temperature magnetron sputtered nanocrystalline (nc-)Ti(N,C)/amorphous diamond like carbon (a-C:H) coatings

Abstract

This paper reports on the structure and mechanical properties of 2μm thick nanocomposite (nc-) Ti(N,C)/amorphous diamond like carbon (a-C:H) coatings deposited on 100Cr6 steel substrates, using low temperature ( 200°C) DC reactive magnetron sputtering. The carbon content was varied with acetylene partial pressure in order to obtain single layer coatings with different a-C:H carbon phase fractions. The nanocrystalline Ti(N,C) phase is approximately stoichiometric for all coatings and the a-C:H phase fraction increases from 31 to 47at.% as the coatings stoichiometry changed from TiC1.34N0.51 to TiC2.48N0.48, respectively. TiC1.34N0.51 coatings showed the highest nanoindentation hardness (H) of 14GPa and a modulus (Er) of 144GPa

H reduced to <6GPa and Er to <70GPa for TiC2.48N0.48 coatings. nc-Ti(N,C)/a-C:H coatings are promising candidates for applications where better matching of the modulus between a relatively low modulus substrate, hard loading support layer and low modulus-high H/E ratio top layer is required. "