Aluminium oxide (Al2O3, also known as alumina) is one of the most popular oxide ceramics, with one of the widest ranges of applications in the engineering industry. The question is what properties does it have that make it such a popular choice?
Aluminium oxide is renowned for being strong and hard – it’s almost as hard as a diamond. As a result it is often used to cut and grind other hard materials. This strength makes it ideal for use as a technical ceramic where strength and performance are vital.
It is very stable even in extremes of temperature. For example the melting point of aluminium oxide is over 1,700°C meaning it resists deformation and can retain its strength under high temperatures. Although it can withstand high temperatures the oxide itself has low heat retention, low specific heat but good thermal conductivity.
Aluminium oxide is an excellent electrical insulator. As a result it can be used to separate elements in electrical circuits ensuring the current is kept on the correct pathway. This contrasts to some other ceramics such as porcelain which can conduct electricity if their temperature is raised.
Aluminium oxide is an amphoteric oxide meaning it can act as both an acid and an alkali. It can resist acid and alkali attacks at high temperatures and is insoluble in water which again adds to its hardwearing and durable qualities. It is also more resistant to corrosion than plastics and metals meaning it can be used in a wider variety of situations.
One of the few downsides to aluminium oxide is that it can demonstrate a poor resistance to fracturing meaning technical ceramics made from aluminium oxide can be sensitive to impact and edge loading. However, the price to performance ratio leans strongly in the favour of using despite this.
If you are interested in using technical ceramics for a range of products from furnaces, grinding media and ballistic armour to pump parts and laser cavities then get in touch with multi-lab. They have advisors on hand to help ensure you buy the right product for your needs and will be able to give you further information on the benefits of using aluminium oxide in technical ceramics.