CVD Diamond Synthesis on WC-Co Cutting Tool via Electrophoretic Seeding Process
- PDF / 432,325 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 65 Downloads / 135 Views
CVD Diamond Synthesis on WC-Co Cutting Tool via Electrophoretic Seeding Process Toshiki Tsubota, Naoki Okada1, Shintaro Ida1, Masanori Nagata, Yasumichi Matsumoto1, Nobumitsu Yatsushiro2 Kumamoto Industrial Research Institute, Material Development Department, 3-11-38 Higashi-machi, Kumamoto, 862-8581, JAPAN 1 Kumamoto University, Faculty of Engineering 2-39-1 Kurokami, Kumamoto, 860-8555, JAPAN 2 KUMABOU METAL 1-4-15 Nagamine, Kumamoto, 862-0937, JAPAN ABSTRACT Electrophoretic deposition was effective for the synthesis of the film type CVD diamond on the WC cutting tool without removing cobalt on the surface, although the adhesion force of CVD diamond was insufficient for the application to a cutting tool. Heat treatment after electrophoretic deposition improved the adhesion force. INTRODUCTION The nuclei density of CVD diamond synthesized on a non-diamond substrate is insufficient for forming a diamond film without an appropriate pretreatment. Several researchers have attempted to utilize electrophoretic deposition as the seeding process for CVD diamond synthesis [1-4]. A number of research works into CVD diamond coating on cutting tools [5-15] have been carried out in order to utilize the highest hardness of diamond. In the case of CVD diamond coating on WC-Co cutting tools, the adhesion force between the WC-Co substrate and the CVD diamond is the most important factor for improving the performance. No researcher has used an electrophoretic deposition for the seeding process of CVD diamond in the case of the diamond coating on a WC-Co cutting tool. Nevertheless, electrophoretic deposition is one of the most promising seeding methods. Electrophoretic deposition is electrically controlled, so the deposition condition can be controlled precisely. Therefore, in this study we attempted to synthesize CVD diamond films on WC-Co substrates via electrophretic deposition, and improve the strength of the adhesion force between CVD diamond and WC-Co substrate. EXPERIMENTAL DETAILS Silicon and commercial WC-Co cutting tools (JIS standard: K-10) were used as the substrate. To eliminate the cobalt on the surface, the WC-Co cutting tools was immersed in dilute HNO3 P5.8.1
solution for 5 minutes, and then rinsed with distilled water. Diamond powder (average diameter = 250 nm) was suspended in solvent at a concentration of 0.1 g L-1. The substrate was dipped in the solvent containing diamond powder, and used as an electrode. The diamond particles were electrophoretically deposited on the electrode. After this electrophoretic deposition, the
℃
WC-Co substrate was heated in an Ar atmosphere at 500 for 2 hours. CVD diamond was synthesized on these substrates using an ECR-MPCVD apparatus. The surface morphologies of these substrates were observed with an SEM and EPMA. XRD measurements were performed for confirmation of the existence of diamond phase in the deposits. The adhesion force between CVD diamond and WC-Co substrate was estimated with Vickers hardness test. RESULTS AND DISCUSSION The diamond powder was suspended in solvents
Data Loading...
