Aluminium oxide is the chemical compound of oxygen and aluminium. The chemical formula of this compound is Al2O3 and its molecular weight is 101.96. It is also commonly called alumina, and may be called aloxide, aloxite, or alundum depending on the particular forms. The high purity aluminium oxide powder is refers to the ultra fine powder material with the purity more than 99.99%. It is one of the most widely used advanced materials in the twenty-first century. The output and production value of this material are very high. The high purity aluminium oxide powder has the following excellent characteristics: high hardness, high strength, high resistance to wear, high resistance to corrosion, high temperature resistance, good insulation, large surface area, small thermal expansion coefficient, good resistance to thermal shock, low dielectric loss and so on. This kind of compound is widely used in high-tech sophisticated materials, such as insulation materials, electronic products, corrosion-resistant material, wear-resistant material and aerospace material. In 1984, H. Gleite, a scientist came from Germany prepared the nano aluminium oxide powder for the first time. From then on, scientists from all over the world did much research work on the preparation of nano aluminiuem oxide powder. Then, many preparation method is proposed, such as ammonium aluminum sulfate pyrolysis method, Ammonium aluminum carbonate pyrolysis method, liquid precipitation method, sol-gel method, organic aluminum alcohol saline solution hydrolysis method and so on.
Ruby and sapphire are two kinds of expensive ornament loved by people. The main ingredient of them is aluminium oxide powder. The reason why ruby is red is that it contains chromium oxide, and the reason why sapphire is blue is that it contains iron oxide and titanium oxide. However, the price of aluminium oxide powder is much lower than the two kinds of jewels. So to the people who see things as they really are may laugh at those who buy ruby or sapphire with a large amount of money.
Aluminium is a kind of metal that is easily to be oxidated and fretted. However, it is still be used in various industrial areas. It is just the aluminium oxide make it possible. The pure aluminium is very prone to react with the oxygen in the air. The result of this reaction is that a thin layer of aluminium oxide film is formed on the surface of the pure aluminium. This layer of aluminium oxide film prevents the aluminium from being oxidated continually. The thickness and performance of this layer of oxide film can be enhanced through a technique called anodization.
Aluminium oxide powder can be added to various kinds of water-based resin, oieoresin, epoxy resin, acrylic resin, polyurethane resin, plastic and rubber. Just with a 3%-5% addition content, it will improve the hardness of these materials dramatically. The hardness can reach to 6H to 8H or even higher. It can also added to heat conduction material, polishing material, electroplating material, catalyst and so on.