THE INFLUENCE OF TITANIUM NITRIDE REACTIVE MAGNETRON SPUTTERING ON HARDENED TOOL STEEL SURFACES

SIS-2140 hardened tool steel was coated with TiN by reactive magnetron sputtering. In this work we have studied the influence of the substrate deposition temperature on the chemical composition at the interface as well as the adhesion and hardness of the TiN film and the substrate. For the chemical composition study, Auger electron spectroscopy, glow discharge optical spectrometry (GDOS) and electron probe microanalysis were used. For the adhesion and hardness measurements, a scratch tester and Vickers micro- and ultramicrohardness testers were used. At a substrate deposition temperature of 400-degrees-C the critical load value is at a maximum. At this temperature the Si:N, Cr:N, C:N, Fe:N, C:Ti and O:Ti (GDOS) relative intensity ratios are also at a maximum. The TiN film shows an adhesive failure mechanism up to 330-degrees-C and a cohesive failure mechanism at higher temperatures. The substrate surface hardness drops from 820 to 470 VHN after TiN deposition at a substrate deposition temperature of 200-degrees-C. The TiN surface and bulk hardness in cross-section increases from 200 to 350-degrees-C and decreases again between 350 and 600-degrees-C.