To simplify preparation and to facilitate handling by dissolving germanium iodide and/or iodine in diiodomethane.
Diiodomethane is used as a solvent and germanium iodide and/or iodine are used as a solute in a heavy liq. compsn. These solutes have specific gravities being larger than that of diiodomethane and they have large solubilities in diiodomethane. When cubic system boron nitride abrasive grains contg. approximately 10wt.% hexagonal system boron nitride are selected by their specific gravities by using this germanium iodide soln. in diiodomethane, the content of hexagonal system boron nitride can be decreased to less than approximately 0.5wt.%. It is possible thereby to obtain a heavy liq. compsn. which is simply prepd. and easily handled and with which selection by specific gravity of diamond and cubic system boron nitride can be performed.
SATO HIRONOBU
SUZUKI MASAHARU
