Deposition and properties of multicomponent hard coatings

Abstract

Hard coatings of titanium carbide, titanium nitride and aluminium oxide are the materials most widely used for improving cemented carbide tools for cutting. The most common technique for the deposition of these layers on carbides is chemical vapour deposition (CVD). In contrast, for physical vapour deposition (PVD), only titanium nitride is commonly used for wear-resistant coatings on tool steels. The PVD process, however, opens up a wide range of opportunities for the deposition of new multicomponent refractory materials. In this work, a systematic investigation of the properties of ternary nitrides and carbonitrides is presented. Alloys of titanium, zirconium, hafnium, vanadium, niobium, chromium and aluminium were selected for the preparation of targets. Coatings of ternary nitrides and carbonitrides, deposited by magnetron sputtering are examined. It was found by X-ray diffraction analysis that most of the deposits have cubic structures with a solid-solution distribution of the metal atoms. Very hard coatings were obtained in the Hf-Ti-N and V-Ti-N systems. Zr-Ti-N coatings showed good resistance and performance in cutting tests. The results of the investigations show that coatings of this class of compounds exhibit properties well suited to providing cutting tools with better protection against wear.