Zhengzhou, China (PRWEB) September 22, 2014
Corundum got its name from India, it is a mineralogy name. Its hardness is second only to that of diamond. Corundum is mainly used as an advanced abrasives material and for bearing materials of wrist-watches and precision machining. The ruby is a sort of synthetic crystal that is utilized as a laser emitting material. Each ruby and sapphire belong to the mineral corundum. Except for asterism effect, only corundum that is transparent or translucent and is bright in colour can be named diamond. The red corundum is referred to as ruby, and corundum with any other colors are named by the joint name–sapphire.

What Is Corundum?

Corundum is formed by Al2O3 crystallization. Corundum that is mixed with chromium requires on a bright red color and is usually called ruby. Corundum with any other colors are considered to be sapphire. Its Moh’s hardness is 9. Its hardness and much less high-priced cost compared with the diamond have made it a favorable material for abrasive paper and abrasive products.

Corundum is a type of synthetic material whose major raw material is aluminum oxide. It can be used as each abrasives and refractory materials. White corundum has a higher purity, and brown corundum includes some impurities.

Synthetic Corundum

Brown corundum is produced by mixing bauxite with higher content of aluminum oxide with anthracite coal or coke and iron filings, which ought to go by way of an smelting process in an electric arc furnace. The carbons are employed to recondition the silicon dioxide and iron oxide in the bauxite. Brown corundum is of superior flow performance, with good crystallization, low coefficient of thermal expansion, great thermal resistance, and very good corrosion resistance. Brown corundum is an indispensable industrial material for abrasives, sandblasting, and refractory material industries.

White corundum is made by melting the higher-purity aluminum oxide powder in an electric arc furnace, and processing the refrigerant ingot into merchandise of all particle sizes. When melting the aluminum oxide powder, if moderate chromic oxide is added, pink fused alumina can be cultivated.

Sintered corundum abrasives are made by grinding the bauxite with the highest content material of aluminum oxide to reduce than ten micrometers and adding moderate additives (such as zirconium oxide or magnesium oxide) and adhesives, which need to go by means of extrusion and be reduce into quick bars.

Corundum Application

As a type of abrasives, corundum is widely used in the abrasives industry. Various types of corundum have different applications.


This is frequently utilised in free of charge grinding, such as coarse grinding before products’ electroplating procedure. Black corundum is also used to make coated abrasives, resin cutting discs, and polishing compounds.

2. Sintered corundum

It is produced of sintered bauxite and aluminum oxide powder and can be produced into abrasive grains of all types. Sintered corundum is primarily employed in heavy load ingot grinding wheels.

3. Zirconia corundum

Its properties are relatively reduce hardness, high toughness, and higher intensity. Zirconia corundum in some foreign nations is utilized in heavy load grinding, such as heat resistant alloy steel, austenitic stainless steel and titanium alloy.


Its colour is rose, and the hardness is related to that of white corundum. Pink corundum has a great grinding overall performance and high grinding precision. Its application consists of all kinds of cutters, fine grinding, and mold grinding of instrument parts.

5. Microcrystal corundum

It is appropriate for grinding stainless steel, carbon steel, cast iron ball milling, etc.

6. Single crystal corundum

The abrasive grains of single crystal are composed of single crystals and have higher hardness and grinding potential. Its disadvantages are high production expenses, waste air and waste water for the duration of production process, and low yields. Single crystal corundum is employed to grind stainless steel, high vanadium and higher speed steel, etc.

7. White corundum

It is appropriate for high speed steel, higher carbon steel, hardened steel, alloy steel, etc.

eight. Brown corundum

Brown corundum contains 94.five% to 97% aluminum oxide. It is extensively used in ordinary steel coarse grinding, such as alloy steel, casting iron, tough bronze, and so forth. The secondary abrasives of brown corundum are employed as resin cutting wheels, abrasive cloth, and abrasive paper.

Author: Liwei Chu 
Copyright: iAbrasive.com–Abrasives & Diamond Tools Marketplace