Skull crucible (original) (raw)

The skull crucible process was developed at the Lebedev Physical Institute in Moscow to manufacture cubic zirconia. It was invented to solve the problem of cubic zirconia's melting-point being too high for even platinum crucibles. Since zirconium oxide in its solid state does not conduct electricity, a piece of zirconium metal is placed inside the gob of zirconium oxide. As the zirconium melts it oxidizes and blends with the now molten zirconium oxide, a conductor, and is heated by radio frequency induction.