We Claim:
1. Abrasive grains based on fused alumina zirconia (AZ) composites comprising additives selected from silica, yttria, chromia and titania.
2. The abrasive grains as claimed in claim 1, wherein the percentage of alumina ranges from 50-65 wt%, and the percentage of zirconia ranges from 32-46 wt%.
3. The abrasive grains as claimed in claim 1, wherein the chromia content is 0-2%, titania is 0 to 3% and yttria less than 1.5% by weight.
4. The abrasive grains as claimed in claim 1, with lamellar structure having repeating units of predominatly alumina and zirconia, with greater than 70% of the microstructure having dimensions of the inclusions, segregations and lamellar regions in the ränge of 100 to 300 nm, and the zirconia structure is a mixture of tetragonal, cubic and monoclinic phases as detected by xray diffraction techniques.
5. A process for preparing the abrasive grains wherein the alumina zirconia and other additives are fused in electric arc furnace and cooled rapidly.
6. A coated abrasive with the abrasive grains as claimed in claim 1.
7. The coated abrasive as claimed in claim 1 comprising other fused or sintered abrasive grains.
8. A resinoid or rubber bonded abrasive wheel comprising the grains as claimed in Claim 1.
9. The resinoid or rubber bonded abrasive wheel as claimed in claim 8, comprising other fused or sintered abrasive grains.
10. A metal matrix composite comprising the grains as claimed in Claim 1 wherein the metal is iron or aluminium based and the grains are dispersed.