Single-crystal diamond tools formed using a focused ion beam: Tool life enhancement via heat treatment

• Published in: Diamond and related materials 2014-10, Vol.49, p.14-18
• Main Authors: Kawasegi, Noritaka, Ozaki, Kazuma, Morita, Noboru, Nishimura, Kazuhito, Sasaoka, Hideki
• Format: Article
• Language: English
• Subjects: Amorphous; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Diamond; Doping and impurity implantation in other materials; Etching; Exact sciences and technology; Focused ion beam; Fullerenes and related materials; diamonds, graphite; Heat treatment; Materials science; Mechanical and acoustical properties; Physical properties of thin films, nonelectronic; Physical radiation effects, radiation damage; Physics; Single-crystal diamond tool; Specific materials; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Tool life; Ultra-precision machining
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2014.07.013

We describe a technique to improve diamond cutting tools used in nanometer- and micrometer-scale machining and formed via focused-ion-beam (FIB) micromachining. Although FIB irradiation is an effective means of fabricating arbitrary miniature shapes in diamond cutting tools, FIB irradiation induces a non-diamond phase, as well as Ga ion implantation, in the irradiated area. This adversely affects the performance of the ultra-precision machining process, especially in terms of tool life and the quality of the machined surface. To eliminate the affected layer, we applied heat-treatment techniques and investigated the optimum thermal profiles. A temperature of 500°C applied to the cutting tool provided optimal machining of nickel phosphorus. The tool life was significantly improved, and a tool life similar to that of a non-irradiated diamond tool was obtained. The quality of the machined surface was also improved markedly owing to superior tool wear and adhesion resistance. •The tool life was significantly improved by proposed heat treatment.•The machined surface quality was improved markedly.•Heating at 500°C was optimal to remove the non-diamond phase from the diamond tools.