Nobuhiro Tajima, Yusuke Taki, Tomohiko Sogo, Hiroyuki Sugimura and Osamu Takai

Department of Materials Processing Engineering, Nagoya University, Nagoya 464-8603, Japan
tajima@plasma.numse.nagoya-u.ac.jp

Amorphous carbon nitride (a-C:N) and amorphous carbon (a-C) thin films were deposited onto WC-Co and Si substrates using shielded arc ion plating (SAIP) developed by our group. Hard a-C:N and a-C films which Knoop hardness was over 5000 were formed at suitable negative substrate bias voltages. This paper reports on the mechanical properties of the films and the relation between the properties and the chemical bonding states in the films. A high-purity graphite target was used as a carbon source. The a-C:N films were prepared in nitrogen and nitrogen-argon gases at the total pressure of 1 Pa with bias voltages of -300 and -400 V. The a-C films were deposited in an argon gas at 1 Pa with a bias voltage of -100 V. The chemical compositions at the surfaces of the films and their chemical bonding states were determined with X-ray photoelectron spectroscopy. Dynamic ultra-microhardness, internal stress and wear resistance were measured for the films. The a-C films showed the best hardness. The a-C:N films were, however, superior in wear resistance to the a-C films.