Aluminium oxide

Aluminium oxide (or aluminum oxide in American English) 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.

Properties

Aluminium oxide is an electrical insulator but has a relatively high thermal conductivity (30 Wm⁻¹K⁻¹) for a ceramic material. It is mechanically very strong and very hard (Mohs 9), second only to diamond and boron nitride.

Occurrence

In nature, aluminium oxide appears in a polymorphic phase, being present as the mineral corundum, most of which is formed as the precious gemstones, ruby and sapphire.

Uses

Aluminium oxide is used in a variety of applications such as: abrasive; refractory material; catalyst; paint; and as a precursor to aluminium.

Health effects

Inhalation of fine aluminium oxide dust can cause health problems such as fibrosis.

See also

• Aluminium
• Oxide
• Corundum
• Ruby
• Sapphire

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