Black Fused Alumina,Black Aluminum Oxide,Black Corundum,Black Fused Aluminum Oxide With high toughness, black aluminum oxide is extremely suitable for polishing stainless steel and non-ferrous metals. It `s grinding efficiency is much higher than that of brown A/O and the finishing effect is much better than many of other abrasive materials. GritAl2O3Fe2O3F220&Coarser62~855F240&Finer60~825