| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject abrasive grains, consisting of a specific polycrystalline cubic boron nitride, capable of maintaining initial machined surface roughness and carrying out good and highly efficient grinding and useful for grind stones for heavy grinding, high speed grinding, creep feed grinding, etc. SOLUTION: The abrasive grains consist of polycrystalline cubic boron nitride in which a molar ratio (B/N) of boron(B) over nitrogen(N) satisfies the relation of the formula: 0.95<B/N<1.00, and do not contain particles having <3.3 specific gravity. The abrasive grains are obtained, e.g. by adding polycrystalline cubic boron nitride abrasive grains containing 10% of hexagonal boron nitride to diiodomethane and agitating the mixture, removing suspended matter in diiodomethane by a siphon, separating a precipitated component by filtration, washing with acetone and drying the precipitate. |
