Excellent raw materials make good hardness and toughness, high efficiency and durability. Black silicon carbide grit F grade 20-220#; 97%min, ... (90% and 97%min); Black silicon carbide micropowder F230-F3000/JIS240-JIS8000 Black silicon carbide is produced from quartz sand and high quality ... strength, for example, grey cast iron, brass, alumina, stone, leather and hard rubber etc. It can also be used ...