Diamond particle shape: Its measurement and influence in abrasive wear

The classification of diamond particles in terms of their abrasive characteristics is addressed in this work. Specifically, diamond particles of different grades have been studied in terms of their shape to identify useful trends and correlations with experimental wear rate. Ten diamond types, typically used by the abrasives industry and exhibiting varied shape, were selected. They included highly geometric single crystals, crushed single crystals, and polycrystalline diamond particles, with nominal diameters of between 65 and 197 μm. Electronic boundary projections were obtained using a digital-camera-equipped optical microscope, which were then processed using proprietary software. The parameters calculated include: diameter (minimum, minor and maximum), aspect ratio, convexity and sharpness. Interesting correlations were found between convexity and sharpness that engendered both these parameters to be considered as useful measures of wear rate. This was reinforced by experimental wear tests, using grinding wheels manufactured from six of the 10 diamond types, which demonstrated excellent correlations of sharpness (0.991 correlation coefficient), and convexity (0.987 correlation coefficient), with the wear rate of a polyurethane workpiece.