Investigation of the possibility of electrical wear by sparking in diamond polishing

In this paper, results are presented from two experiments whose common aim was to investigate the possibility, suggested by some workers, of an electrical type of wear mechanism in diamond polishing. The first experiment involved deliberately generating sparks between the surface of the diamond specimen and a probe charged at high voltage placed above it. The surface was subsequently examined for damage or wear. In the second experiment, a high-speed camera was used to monitor the movement of the specimen upon the scaife during ''zero-load'' polishing, i.e. during polishing in which the specimen is not apparently in contact with the wheel and yet wear is observed to occur. The results from the first experiment suggest that electrical mechanisms are not responsible for the polishing of diamond, and in the second experiment, the specimen was found to impact the wheel at points during sliding thus indicating that mechanical processes can account for wear when contact between the diamond and the wheel takes place. Simple estimates suggest that attraction between the rotating surfaces can be either electrical or aerodynamic. (C) 1997 Elsevier Science S.A.