Abstract
MgO single crystal is lapped and polished. The function of abrasive grains in lapping process is discussed on the basis of aspects of worked surface. Surface roughness and the depth of dislocation concentrated zone are measured. Obtained results indicate that machining mechanism varies as the size of abrasive grains used. When coarce grains are used, principal machining process is microfracturing produced by the pressing of each grain. On the other hand, when fine grains are used, it is micro-cutting by grain tips. Measurement of the depth of dislocation concentrated zone clarifies average weights on each grain. There is much diffrence in average weights between the case when coarce and fine grains are used. It is assured that this is the cause of the difference between machining mechanisms mentioned above. Furthermore, obtained values of average weight indicate that grains with especially large size may be crushed in earlier period of lapping.
