MECHANICAL APPLICATIONS OF THIN AND THICK DIAMOND FILMS

Several applications of thin and thick diamond films have been developed in our laboratory which enable us to exploit the well-known property of diamond, i.e. the highest hardness on earth. These applications include cutting inserts of either a coated (thin film) type or a brazed (thick film) type whose performance has been evaluated and compared with both conventional sintered and single-crystal diamond insert (tool) as well as tungsten carbide insert in cutting very-hard-to-turn materials such as a 18 wt.% Si aluminium alloy or a dispersion-strenthened aluminium alloy including 20 vol.% SiC whiskers. The performance test is extended to a precision turning operation of pure aluminium which requires a very good surface finish. Other applications of diamond film here have been found in antiabrasive tools; one is a dresser used for forming grinding wheels and another is a shearing tool for cutting very abrasive materials such as a polishing tape with a top SiC coating layer. Finally, the development of an indenter mounting a thick diamond film flake shaped into a scratch tester tip has been explained as one example of diamond films for use as various mechanical parts or elements.