Ceramic is a hard, brittle material made by shaping a nonmetallic inorganic substance, such as clay, and firing it at high temperature. It resists heat and corrosion. In watchmaking, zirconium dioxide, also called zirconia, is the ceramic used for many cases.
How is watch ceramic made?
Watch ceramic starts as a powder. The powder is packed with a binder into a pre-blank, which is then fired at very high temperatures. The binder burns off during firing. Afterwards, the part must be cooled carefully. Rado makes its high-tech ceramic from a very fine zirconium oxide powder. It mixes in pigments to give the material its colour. Rado fires, or sinters, its parts at 1,450°C. As they become fully dense, they shrink by about 23%.
How strong is ceramic?
Ceramics cope well with being squeezed. They are weak, though, under shear and tension, when forces slide parts of the material against each other or pull it apart. Hard does not mean unbreakable. Zirconium oxide is very hard, but it can still break. IWC found that rounder case shapes lowered that risk. Rado’s ceramic is said to be ten times harder than gold and two and a half times lighter.
Which watches have used ceramic?
IWC began offering ceramic as a case option in 1986, on the Da Vinci Perpetual Calendar Chronograph. The ceramic it used first was zirconium oxide. Early ceramic cases came in only a few colours, and IWC made just black and white versions for its own collection. In 2015, Omega released The Dark Side of The Moon, a watch made entirely of zirconium dioxide. Some cases are sold under the name black zirconium oxide, although zirconium dioxide itself is a white crystalline oxide.
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