Cobalt is a metallic element. In watchmaking, it is the base of several alloys. Cobalt-based alloys are prized because they are very strong, resist corrosion well and stay stable at high temperatures. Watchmakers use them for balance springs and, as cobalt chrome, for cases.
Where it comes from
The name comes from the German word kobold, which means goblin. German miners already used this goblin name for a certain ore. In 1735 the Swedish chemist Georg Brandt found a metal in that ore and identified it as a new element. He also showed that the blue colour added to glass came from cobalt. Until then, people had believed it came from bismuth. When Brandt named the new element, he kept the miners’ term.
What is cobalt chrome?
Cobalt chrome is a cobalt alloy that is very strong and hard, and it resists corrosion. It looks rather plain, but a cobalt chrome case shines differently from one made of stainless steel or titanium. It is strong for its weight and is compatible with the human body. Outside watchmaking, it is widely used in medicine and in aviation, for example in turbines. Roger Dubuis is described as the first watchmaker to use cobalt chrome for a watch. No high-end watch had a cobalt chrome case before the Roger Dubuis Excalibur. The MicroMelt production method gives the material an even density, which makes it stronger.
What other cobalt alloys are there?
Nivaflex is a cobalt alloy made specifically for watchmaking. It is used mainly for balance springs. Phynox is another cobalt alloy, and it also contains chromium and nickel. It can be hardened. Hardening does not cost it its other qualities: it still balances strength, corrosion resistance and ease of shaping. Both names refer to alloys based on cobalt, not to the pure element.
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