Observations on the Polishing of Bismuth Silicon Oxide Crystals

Abstract

The present paper describes our observations on the polishing of bismuth silicon oxide (Bi₁₂SiO₂₀) crystals. It is not easy to polish the BSO crystal un the conventional pitch polisher which is used for the polishing of glasses. Several pitch polishers having composition of pitch and rosin in different proportions were prepared in search of a suitable polisher for BSO crystal. It was found that a mixture of 800 g hard pitch and 100 g rosin makes the correct proportion for preparation of a pitch polisher provided 90 nil of turpentine oil is added to this mixture in order to obtain die required medium soft pitch suitable for polishing BSO crystal. A BSO crystal of si/e 19 mm × 19 mm × 9 mm was successfully polished on the pitch polisher usingjhe above composition. The polishing time using 0.3 micron gamma alumina (Buchler micropoiish B) ponder as the polishing compound and 60 rpm as the rotating speed of the polisher is about one hour.