Polishing and Lapping Materials

finely dispersed powdery substances, as well as pastes and suspensions having these substances as a base, used in polishing and lapping. The powders used for polishing are classified as hard, such as diamond or corundum, or soft, such as ultramarine and oxides of iron, chromium, and aluminum. Hard powders, with a grain size of 0.1 to 60 microns, are used in lapping and preliminary polishing. Final polishing is done with soft powders, of which metal oxides have the greatest polishing capability. In polishing, the polishing and lapping materials are primarily used in paste and suspension form. Pastes consist of polishing powders, fats, binders, surface-active agents, and other substances. Suspensions are composed of powders, acid and alkaline solutions, and corrosion inhibitors.