Abstract: Microcrystalline bodies based on .alpha.-Al.sub.2 O.sub.3 are made by drying sub-micron powders, press compacting and shock sintering at an intermediate sinter temperature range of 1,300.degree. to 1,550.degree. C., i.e. bringing the compact up to such range in under 60 seconds, preferably under 10.

Abstract: The invention relates to an abrasive material based on .alpha.-Al.sub.2 O.sub.3 and ZrO.sub.2 with a content of titanium compounds in the form of suboxides, carbides and/or oxycarbides, to a process for its production and to its use.

Abstract: A process for the production of abrasive materials by pouring molten abrasive material into the spaces between plates of an assembly of moving cooling plates. The pour is followed by solidification and removal of the poured material (and size reduction of the removed material). The plates are maintained parallel and vertical throughout the pouring, solidification and removal steps, the latter being accomplished by separation of the plates by a conversion wheel. The motion of the plates is then reversed by the wheel to reassemble the plates for a new cycle of pour, solidification and removal.

Abstract: Colored corundum composite with a matrix of .alpha.-Al.sub.2 O.sub.3, as formed by sol-gel process ending in sintering and size reduction steps with addition of oxide pigments (or precursors of such oxide pigments, formable to the oxide pigment in sinter heating) added to the sol before full gelation thereof.

Abstract: Sintered composite abrasive material useful in abrasives (grinding wheels, abrasive discs and paper, etc.) and cutting tools, comprising an .alpha.-Al.sub.2 O.sub.3 matrix of sub-micron crystallite size made by sol-gel processing with a dispersed phase therein of mechanically resistant material, preferably essentially isotropic grains, added directly to the sol or gel stage of matrix formation.