Aluminum oxide is the most commonly used abrasive.
Coated abrasives can be used for most applications, from grinding to polishing. Coated discs are normally used on angle grinders. 150 Grit 5 Inch Diameter No-Hole PSA Sanding Paper (Ceramic Aluminum Oxide), PK 25.They consist of a thin layer of abrasive adhered to fiber, paper, cloth or rubber.