Investigation of superlattice coatings deposited by a combined steered arc evaporation and unbalanced magnetron sputtering technique

Abstract

In this paper we report on third-generation TiA1N-ZrN superlattice thin films deposited at industrial scale on high speed steel and stainless steel substrates by a combined steered arc evaporation and unbalanced magnetron sputtering technique. The superlattice period and hence the mechanical and physical properties of the film were varied by modification of the rotation velocity and type of rotation (one-fold and three-fold). Characterization of the films was undertaken by a range of bulk and surface analysis techniques including scanning electron microscopy, X-ray diffraction, glow discharge optical emission spectrometry, hardness and adhesion measurement. Results show that a reproducible superlattice structure can be fabricated without a complex atmosphere separation and shuttering mechanism. Control of the planetary rotation velocity and type of rotation has led to variation in the superlattice period from 19 to 132 Å. Further analysis has shown that the TiA1N-ZrN superlattice system can exhibit hardness greater than 4000 HK, scratch adhesion values on high speed steel of above 50 N, <100> preferred orientation, average surface roughness less than 0.10 μm and a highly dense microstructure.