黑刚玉又名低铝刚玉是于电弧炉中，将铝矾土熔炼而制得的一种以 α- Al2O3 和铁尖晶石为主矿相的灰黑色结晶体，其特点是Al2O3 含量较低，并有一定量的Fe2O3（10%左右）存在，因而具有硬底适中、韧性高、耐高温、热态性能温定的特点。特别适合做高速公路、机场跑道、大桥路面等的耐磨防滑材料，适合做耐磨防滑地坪材料。是优质的抛光研磨材料。具有硬度适中，韧性、自锐性、粘结性良好，经久耐用等特点。磨削时发热量小，不易划伤工件表面，不易引起工件表面变色，加工后工件表面光洁度高、色差极小。主要用于金属工件等研磨抛光，特别适合于不锈钢工件的研磨抛光，亦适用于光学玻璃、木材等材料的抛光，也大量用于制成树脂磨具，砂带等涂附磨具。
Black fused alumina is also known as low aluminum corundum. It is a dark gray crystal body with α- Al2O3 and ferropicotite as main ore by smelting the bauxite in the electric arc furnace. Black fused alumina is characterized by low Al2O3 and a certain amount of Fe2O3 (10% more or less) content, so it has characteristics of moderate hardness, high toughness, high temperature resistance, and stable thermal stability. It is mainly suitable for wear-resisting and antiskidding materials in expressway, airport pavement, bridge pavement. It is a high-quality polishing and abrasive materials with the characteristics of moderate hardness, toughness, self-sharpening, and good cohesiveness, durable in use. It is mainly used for polishing and sandblasting of stainless steel, fabricated metal products, optical glass, bamboo products, and it is widely used in manufacturing the resin abrasives and coated abrasive tools, with the characteristics of strong cutting power, high toughness, high flexibility, good abrasion resistance.
 
 
黑刚玉指标：Black Fused Alumina indexes