Aluminium oxide is a chemical compound of aluminium and oxygen with the chemical formula Al2O3. It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium(III) oxide. It is commonly called alumina, and may also be called aloxide, aloxite, or alundum depending on particular forms or applications. It commonly occurs in its crystalline polymorphic phase α-Al2O3, in which it comprises the mineral corundum, varieties of which form the precious gems ruby and sapphire. Al2O3 is significant in its use to produce aluminium metal, as an abrasive owing to its hardness, and as a refractory material owing to its high melting point.[5
Al2O3 is an electrical insulator but has a relatively high thermal conductivity (30 Wm−1K−1[1]) for a ceramic material. Aluminium oxide is completely insoluble in water. In its most commonly occurring crystalline form, called corundum or α-aluminium oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools.
Al2O3 is an electrical insulator but has a relatively high thermal conductivity (30 Wm−1K−1[1]) for a ceramic material. Aluminium oxide is completely insoluble in water. In its most commonly occurring crystalline form, called corundum or α-aluminium oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools.
