HIGH ADHESION AND QUALITY DIAMOND FILMS ON STEEL SUBSTRATE

A process to deposit a diamond coating on steel substrates has been su ccessfully developed. It includes the electroplating of nickel by usin g an electrolyte dispersed with micro-diamonds, and then a diamond dep osition through a microwave plasma chemical vapor deposition system. T he diamond films were characterized by Raman and CL spectroscopy, XRD, SEM and SEM line scanning. The results show a high diamond crystal qu ality, low residual stress (about 0.67 GPa) and high nucleation densit y. The adhesion of the films was evaluated by a cutting test and an in terface examination. The results show that the retentivity of the diam ond grits in the films after the cutting test is much better than that in the commercial electroformed diamond tools. The advantages of the process are: (1) the formation of nickel-carbon-hydrogen alloys to enh ance diamond nucleation and growth, (2) the micro-diamonds acting as t he seeds for diamond nucleation and growth, and forming effective mech anical interlocking with the nickel interlayer, and (3) the formation of good diffusion bonding of the nickel interlayer with the steel subs trate. (C) 1998 Elsevier Science S.A.