THE EVALUATION OF SELECTED PROPERTIES OF TI AND CR BASED COATINGS DEPOSITED ONTO HSS CO5

Abstract

This study investigates the properties of thin Ti and Cr based coatings applied by two PVD techniques. ARC and SARC PVD techniques were used for the deposition of thin coatings onto HSS Co 5 steel. Conventional types of coatings (monolayers TiN, TiAlN, CrAlN), and an advanced type of coating (Ti and Al based KTRN monolayer deposited by smaller drops on the surface) were analyzed by standard techniques for surface status and quality assessment – coating thickness, chemical composition by EDX analysis, hardness and coefficient of friction (COF) at room temperature. Measured nano-hardness of CrAlN, TiAlN, KTRN, and TiN coatings were 16.5 GPa, 34.7GPa, 34.9GPa and 14.3GPa, respectively. Measured COF values of CrAlN, TiAlN, KTRN, and TiN coatings were 0.58, 0.48, 0.57, and 0.82 respectively. The roughness Ra of CrAlN, TiAlN, KTRN, and TiN coatings were 0.31µm, 0.31 µm, 0.58 µm and 0.76 µm, respectively. Lower deposition temperature and specimen distance to the target can be the reason of lower hardness of TiN and CrAlN coatings. High values of the roughness Ra and higher contact surface size of the system coating-ball are the reasons for high COF of TiN coating.