Characterization of hard nitride and carbide titanium and zirconium coatings on high‐speed steel cutting tool inserts

Abstract

Hard nitride and carbide coatings of titanium and zirconium deposited by reactive evaporation and reactive sputtering techniques were characterized by electron microscopy and Auger spectroscopy to determine the effect of coating process on coating composition and microstructure. Analysis of the chemical composition by Auger spectroscopy revealed the coatings were of high purity with slight differences in stoichiometry depending on the coating technique. Both techniques produced coatings with a columnar microstructure. However, the reactive sputtering technique produced coarser (shorter and wider) columnar grains than the reactive evaporation technique. Furthermore, selected area diffraction analysis of reactively sputtered ZrN coatings showed a two‐phased zone (hcp Zr and fcc ZrN) near the substrate/coating interface, while TiC coatings deposited by reactive sputtering and evaporation only showed a single‐phase region of fcc TiC.