Understanding the Characteristics of Eight Different Abrasives

Abrasives can be classified into various types based on their composition and performance, including brown fused aluminum oxide, white fused aluminum oxide, pink fused alumina, zirconia fused alumina, black fused alumina, black silicon carbide, green silicon carbide, and boron carbide abrasives. Below is an overview of the characteristics of these abrasives:

Brown Fused Aluminum Oxide

Brown fused aluminum oxide is an artificial corundum smelted in an electric arc furnace. Its main component is Al2O3, with a content usually ranging between 95%-96%. Brown fused aluminum oxide has high hardness (HV=1800-2200 kg/mm²), good toughness, and a high melting point (1800~2000℃). Therefore, it is widely used in processing carbon steel, alloy steel, malleable cast iron, and hard bronze. Its appearance is brown grains, and the coarser the grain size, the darker the color. Identification is typically done through physical testing and chemical analysis.

White Fused Aluminum Oxide

White fused aluminum oxide is made from alumina powder that is melted and recrystallized in an electric arc furnace. Its main component is AL2O3, with a content exceeding 98.5%. White fused aluminum oxide has hardness (HV=2200~2300 kg/mm²) slightly higher than brown fused aluminum oxide but lower toughness, making its abrasive grains prone to fracture during grinding. Due to its low heat generation, it is suitable for grinding quenched steel, high-carbon steel, and high-speed steel. Its appearance is white, with coarse grains being off-white and finer grains being whiter. Identification methods include chemical analysis and petrographic analysis.

Pink Fused Alumina (Chrome Alumina)

Pink fused alumina is produced by adding 0.5%~2.0% chromium oxide to alumina powder and then smelting in an electric arc furnace. It appears rose-pink. Its hardness is similar to white fused aluminum oxide but with higher toughness. Pink fused alumina grinding tools are commonly used for fine grinding cutting tools, gauges, and instrument components. Its grinding performance is superior to white fused aluminum oxide and is mainly used for precision machining.

Zirconia Fused Alumina

Zirconia fused alumina is made from raw materials such as alumina, zircon sand, etc., through high-temperature smelting in an electric arc furnace, appearing grey-white. Its microcrystalline structure has high toughness, strength, and wear resistance. Zirconia fused alumina shows high efficiency and good roughness in rough grinding, coarse grinding, and heavy-load grinding of steel and is suitable for grinding heat-resistant alloy steel, drill alloys, and austenitic stainless steel.

Black Fused Alumina

Black fused alumina is smelted from bauxite in an electric arc furnace, with a chemical composition of Al2O3>77%, containing about 10% Fe2O3. It appears black and has lower hardness than brown fused aluminum oxide. It is commonly used for polishing, thus also called polishing sand or polishing powder, and was widely used in coated abrasives.

Black Silicon Carbide

Black silicon carbide is made from raw materials such as quartz sand and petroleum coke in a resistance furnace, with a chemical composition primarily SiC>98%. It has high hardness (HV=3100~3300 kg/mm²), low toughness, and is commonly used for grinding and cutting non-ferrous materials like non-ferrous metals, wood, leather, and plastic. Black silicon carbide is heat-resistant, chemically resistant, and resistant to thermal shock, making it widely used as a refractory material.

Green Silicon Carbide

Green silicon carbide is made from raw materials such as quartz sand and petroleum coke in a resistance furnace, and it appears green. Its chemical composition is SiC>99%. It has even higher hardness (HV=3200~3400 kg/mm²), making it suitable for processing high-hardness and brittle non-ferrous materials like hard alloys and optical glass, and is also used in the manufacture of silicon carbide rods.

Boron Carbide Abrasives

Boron carbide is black and has a higher hardness than silicon carbide (HV=5000 kg/mm²). Due to its tendency to oxidize and decompose at high temperatures, it is usually not used in making grinding tools but is suitable for grinding or polishing high-hardness materials such as synthetic sapphire and watch glass.

These abrasives each have unique characteristics. Selecting the appropriate abrasive according to different processing needs can improve the processing effect and efficiency.