U.S. 8,197,791 B2
Evonik Degussa GmbH has obtained a patent for an aluminium oxide powder in the form of aggregates of primary par- ticles, wherein each particle has a BET surface area of from 10 to 90 m2/g and is comprised of as crystalline phases, in ad- dition to gamma-aluminium oxide and/ or theta-aluminium oxide, at least 30% by weight of delta-aluminium oxide, and wherein the aluminium oxide powder has a tamped density of 10 to 200 g/l.