NOBLE METAL PRODUCT HAVING TRANSPARENT HARD FILM ON SURFACE

摘要

PURPOSE:To improve the weather and scratch resistances of a noble metal product by forming a film of transparent hard ceramics or carbon on the surface of the product. CONSTITUTION:A film of transparent hard ceramics such as Al2O3, ZrO2, SiO2, Si3N4 or AlN or transparent hard carbon such as amorphous carbon or diamond is formed on the surface of a noble metal product contg. one or more kinds of metals such as Au, Pt, Ag and Cu. The preferred thickness of the protective film is 0.1-10mum and the film is formed by vapor phase synthesis or other method. A ceramic coating may be formed by applying metallic alcoholate to the product and heating it. The noble metal product having the protective film maintains weather and wear resistances for a long period.