[19p-P4-1~15] 6.2 Carbon-based thin films

[19p-P4-11] Negative Bias Effects on Growth and Mechanical Properties of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films Deposited on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition

〇Tsuyoshi Yoshitake¹, Ali M. Ali^1,2, Mohamed Egiza^1,3, Kouki Murasawa^1,4, Yasuo Fukui⁴, Hidenori Gonda⁴, Masatoshi Sakurai⁴ (1.Kyushu Univ., 2.Al-Azhar Univ., 3.Kafrelsheikh Univ., 4.OSG Co. Ltd.)

Keywords:nanocrystalline diamond, negative bias, hard coating

Ultrananocrystalline diamond (UNCD) /nonhydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were deposited on negatively biased WC-Co substrates by coaxial arc plasma deposition, and the effects of negative bias on the growth and mechanical properties of the films were studied. The negative bias voltage was applied in pulsed process at 40, 60, and 80 kHz. The 49 GPa hardness films were deposited at a thickness of 8.8 µm, which is more than an order of magnitude more than that of comparably hard diamond like carbon films deposited by arc ion plating deposition. In addition, the deposition rate evidently increased under the negative bias. This might be because the negative bias enhances the attraction of positively charged carbon species to the substrates, which results in enhanced film adhesion on the substrates and the release of film internal stresses.