Corundum Categories & Properties Analysis
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 kind of synthetic crystal that is used as a laser emitting material. Both ruby and sapphire belong to the mineral corundum. Except for asterism effect, only corundum that is transparent or translucent and is bright in color can be called diamond. The red corundum is called ruby, and corundum with any other colors are called by the joint name--sapphire.
What Is Corundum?
Corundum is formed by Al2O3 crystallization. Corundum that is mixed with chromium takes on a bright red color and is generally called ruby. Corundum with any other colors are considered to be sapphire. Its Moh’s hardness is 9. Its hardness and less expensive price compared with the diamond have made it a favorable material for abrasive paper and abrasive products.
Corundum is a kind of synthetic material whose main raw material is aluminum oxide. It can be used as both abrasives and refractory materials. White corundum has a high purity, and brown corundum contains some impurities.
Synthetic Corundum
Brown corundum is made by mixing bauxite with high content of aluminum oxide with anthracite coal or coke and iron filings, which should go through 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, good thermal resistance, and good corrosion resistance. Brown corundum is an indispensable industrial material for abrasives, sandblasting, and refractory material industries.
White corundum is made by melting the high-purity aluminum oxide powder in an electric arc furnace, and processing the refrigerant ingot into products 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 of aluminum oxide to lower than 10 micrometers and adding moderate additives (such as zirconium oxide or magnesium oxide) and adhesives, which should go through extrusion and be cut into short bars.
Corundum Application
As a form of abrasives, corundum is widely used in the abrasives industry. Different types of corundum have different applications.
This is commonly used in free grinding, such as coarse grinding before products’ electroplating process. Black corundum is also used to make coated abrasives, resin cutting discs, and polishing compounds.
2. Sintered corundum
It is made of sintered bauxite and aluminum oxide powder and can be made into abrasive grains of all types. Sintered corundum is mainly used in heavy load ingot grinding wheels.
3. Zirconia corundum
Its properties are relatively lower hardness, high toughness, and high intensity. Zirconia corundum in some foreign countries is used in heavy load grinding, such as heat resistant alloy steel, austenitic stainless steel and titanium alloy.
Its color is rose, and the hardness is similar to that of white corundum. Pink corundum has a good grinding performance and high grinding precision. Its application includes all kinds of cutters, fine grinding, and mold grinding of instrument parts.
5. Microcrystal corundum
It is suitable 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 high hardness and grinding ability. Its disadvantages are high production costs, waste air and waste water during production process, and low yields. Single crystal corundum is used to grind stainless steel, high vanadium and high speed steel, etc.
7. White corundum
It is suitable for high speed steel, high carbon steel, hardened steel, alloy steel, etc.
Brown corundum contains 94.5% to 97% aluminum oxide. It is widely used in ordinary steel coarse grinding, such as alloy steel, casting iron, hard bronze, etc. The secondary abrasives of brown corundum are used as resin cutting wheels, abrasive cloth, and abrasive paper.
Author: Liwei Chu
Copyright: iAbrasive.com--Abrasives & Diamond Tools Market
Lei, iAbrasive.com, http://www.iabrasive.com/, +86 37186167220, [email protected]
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