[19p-F206-1~10] 6.2 Carbon-based thin films

[19p-F206-2] Doping Effects of Silicon on Mechanical Properties of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films Deposited on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition

〇Tsuyoshi Yoshitake¹, Mohamed Egiza^1,2, Kouki Murasawa^1,3, Ali M. Ali^1,4, Yasuo Fukui³, Hidenori Gonda³, Masatoshi Sakurai³ (1.Kyushu Univ., 2.Kafrelsheikh Univ., 3.OSG Co. Ltd., 4.Al-Azhar Univ.)

Keywords:nanocrystalline diamond, hard coating, coaxial arc plasma

Si-doped ultrananocrystalline diamond/amorphous carbon composite films were deposited on cemented carbide (WC-Co) substrates by using coaxial arc plasma deposition with Si blended graphite targets. The doping of Si degrades the hardness and modulus. From energy-dispersive X-ray spectroscopic measurements, the diffusion of Co atoms from the substrates into the films were observed for the films. Since the Co diffusion induce the graphitization due to the catalytic effects, the degraded hardness and modulus should be attributable to the catalytic effects of Co. On the other hand, Si-doped films were deposited on a thin undoped UNCD/a-C buffer layers deposited on WC-Co substrates. It was found that the undoped UNCD/a-C layer prevent from the Co diffusion, which results in an enhancement in the hardness to 60 GPa. The details will be reported at the conference.