WEAR RESIDUE FROM POLISHING SAPPHIRE WITH SILICA AQUASOL ON A TIN LAP

Sapphire can be superpolished with a tin lap and aqueous colloidal sil ica as a polishing liquid. We present investigations of the polishing residue that was enriched in a special wearing mill. Elemental analysi s, X-ray analysis by diffraction and MAS-NMR studies were performed to obtain an understanding of the microscopic polishing mechanism. We co nclude that sapphire is abraded atom by atom in this polishing procedu re and that the abraded aluminum atoms are finally chemically bonded i n the colloidal silica clusters, in contrast to models proposed earlie r.