THE EFFECT OF BIAS VOLTAGE ON OXIDATION BEHAVIOR OF MONOLAYER TiAlN AND MULTILAYER TiAlN/AlN COATINGS

摘要

TiAlN coatings have been known to be superior to other coatings such as TiN and TiCN in protecting tools which may be damaged by high thermal load. It is well known that multi-layered coatings indicates better thermo/mechanical properties than mono layered coatings. Monolayer TiAlN coating have less oxidation resistance than multilayer TiAlN/ AlN coatings. In this study, TiAlN/AlN multi layer coatings were deposited at different bias (self bias, -30V, -60V) voltages by the method of physical vapor deposition (d.c. magnetron sputtering) on steel substrates. Experimentally all coatings are oxidized as isothermals for 1 hour at 800 deg C to inspect oxidation of the films. Then oxidised surfaces were characterized by optic microscopy, electron micsroscopy (SEM) and EPMA. Crystal structure were analyzed using XRD. It was found that bias voltage increase to the coating density and oxidation resistance.