A type of super-abrasive

Zirconia Alumina is a kind of abrasive . It is a kind of super-abrasive for coated abrasives ,I think. This type of abrasive has a unique self-sharpening feature that gives them long life on rugged stock removal operations. Thus, Zirconia alumina is fantastically suited for heavy grinding of metals and planing of wood, because the controlled fracturing of the grain continuously produces sharp, new abrading points.  ZA used to make grinding wheel , but it has been used to apply in the coated abrasives since 90s.