Zirconia alumina is commonly used as a
sand-blasting medium. It is typically used as an
abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflec ...
in
casting
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a ''casting'', which is ejected ...
and
foundry
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals pr ...
processes. Zirconia alumina is a mixture of
zirconium dioxide
Zirconium dioxide (), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabi ...
and
aluminium oxide.
Zirconia toughened alumina typically consists of alumina with a 10 to 20 percent zirconia concentration, which enhances the toughness of the alumina. To achieve the increase in the composite's strength, a process known as stress induced transformation toughening takes place. Stress induced transformation toughening results in uniform internal strain, which causes the zirconia structure to crack, and the zirconia particles to switch phases. Because of this phase switch, the amount of zirconia particles increases and creates stresses within the alumina's structure. These stresses effectively heal the crack and block further cracking—the added zirconia doubles the composite's strength and enhances toughness between two and four times.
Zirconia Alumina
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See also
* Zirconia Toughened Alumina
References
Abrasives
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