Treibacher Chemische Werke Aktiengesellschaft

Herwig Winkler

Peter Janz

Georg Gottschamel

Abrasive material with particularly high abrasive performance is obtained in that the ceramic material contains an additive of 0.01 to 15 percent by weight, preferably 0.1 to 3 percent by weight of a chromium compound.

Sintered microcrystalline ceramic material

Ceramic sintered body, in particular abrasive grain, based on .alpha.-Al.sub.2 O.sub.3, said body being arranged in such a manner that improved abrasive results are achieved, said body being bound into a structure by means of a glass-like ceramic binder and showing a drop in hardness from its center to its edge of less than 1800 N/mm.sup.2, preferably less than 1000 N/mm.sup.2, and, in particular, less than 500 N/mm.sup.2.

Ceramic sintered body and method of producing it

Sintered microcrystalline ceramic material based on .alpha.-Al.sub.2 O.sub.3 with an addition of 0.01 to 2.0 weight percent of a cerium compound, consisting of a microcrystalline matrix and 0.1 to 30 volume percent whisker-like needles, whereby said cerium compound is mainly present in the needles. The whisker-like needles give this material a special tenacity combined with good abrasive results.

An abrasive material of great hardness and high tenacity particularly suitable for high-pressure grinding consists essentially of a sintered, microcystalline .alpha.--Al.sub.2 O.sub.3 abrasive material having a purity of least 98.5% and a density of at least 95% of theoretical density, the .alpha.--Al.sub.2 O.sub.3 crystallites of the material being smaller than 4.mu., preferably smaller than 3.mu..

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Klagenfurt, Austria

Herwig Winkler