Abrasives contg. alumina and silicon carbide - plus small amts. of carbon and/or magnesia which increase the hardness and grinding power of the abrasives

摘要

Parent patent described abrasive compsns. possessing high hardness, and contg. 1-40% SiC and 99-60% alumina, the SiC crystals being dispersed in a matrix of Al2O3. The initial mixt. was hot pressed at max. 1900 degrees C and max 300 bars; or pressed cold at min 100 bars and sintered 1-24h at 1500-1900 degrees C in a non-oxidising atmos. In this addn the mixt of alumina and SiC also contains by wt. 0.1-0.5% carbon; and a pref. mixt. contains 0.1-0.5% MgO. The esp pref. mixt. contains 0.1-0.5% carbon together with 0.1-0.5% Mgo. The object of the present invention is to increase the desnity of the pressings obtd. and also to improve their performance as an abrasive. Used for all types of abrasive, e.g. abrasive cloth or paper; slitting or grinding discs or wheels; saws, laps or drills; drawing dies or guides; wear resistant components; shot blasting or rumbling shot.