With physical vapour deposition (PVD), an ionized metal vapour is generated from high-purity, solid coating material, which forms a coating mixture together with noble gases. A thin layer is deposited on the workpiece surfaces through condensation. PVD processes are carried out under high-vacuum conditions in a coating chamber. The process is one of the most advanced and ecologically sustainable coating technologies. The thin PVD layers are more scratch-resistant and durable than conventional gold coatings. PVD coatings can be gold-coloured, blue or grey in appearance.