Aluminum Oxide

A Versatile Material

Aluminum oxide (Al2O3) can exist in a number of different forms. The most important are cubic ?-Al2O3 and trigonal ?-Al2O3 (corundum), and the hydroxides Al(OH)3 (gibbsite; bayerite/alumina trihydrate/ATH) and AlO(OH) (boehmite, diaspore). At a certain temperature, water-insoluble aluminum oxide converts into ?-Al2O3, which is also insoluble in acids and bases, making for a highly resistant material.

Aluminum Oxide Applications and Production

To produce aluminum oxide, the natural ore bauxite is dissolved in a sodium hydroxide solution, forming aluminum hydroxide. This is then sintered or calcined in a rotary kiln to drive off the water, yielding aluminum oxide (Smelter Grade Alumina, SGA).

Economically the most important use of aluminum oxide is as a precursor for metallic aluminum; 90% of global aluminum oxide production is used for this single purpose. However, alumina have many more uses: In the chemical industry, it comes into play as an adsorbent, as a carrier material for catalysts and as a catalyst in its own right. The high hardness makes it an ideal abrasive and polishing agent and sintered aluminum oxide (corundum) is used as a refractory material in high temperature environments like furnaces. Aluminum oxide-based ceramic materials are also vital in modern electronics; their low dielectric loss factor makes them ideal dielectric materials.

Calcined aluminum oxide is also used in high-performance ceramics, saving lives as ballistic armor or making life more livable as an implantable prosthetics.

Aluminum oxide is highly suitable for mechanical applications that require high resistance to friction and wear, impact protection and corrosion resistance. Additionally, since its melting points are higher than 2000 °C, applications at temperatures of up to 1900 °C (3453 °F) are possible.

Aluminum Oxide – Experience

The material characteristics of aluminum oxide based ceramic depends largely on the purity of the starting materials and the production process. The higher the purity of the aluminum oxide, the higher the quality of the ceramic material. Therefore, it is absolutely vital to prevent contamination. Failure to do so can result in very costly production mistakes.

At IBU-tec, we have been successfully preforming this process for decades and our comprehensive set of process equipment offers the ideal conditions for pilot testing and/or production. If you need help with a project involving aluminum oxide, please contact us. We will be happy to advise you.