Patent ID: 7771836

Claim:
A process for producing a golden ornament, comprising the steps of: forming a Ti coating film on a surface of a base material by evaporating titanium in a dry plating apparatus in an atmosphere of an inert gas other than nitrogen in such a manner that titanium is evaporated in a constant amount per unit time; forming a TiN gradient coating film whose N atom content has a gradient in the thickness direction on the Ti coating film by introducing a nitrogen gas in the dry plating apparatus in such a manner that the nitrogen amount is increased with time in the dry plating apparatus while evaporating titanium in the dry plating apparatus in such a manner that titanium is evaporated in a constant amount per unit time; forming a TiN coating film on the TiN gradient coating film by keeping the nitrogen amount constant in the dry plating apparatus while evaporating titanium in the dry plating apparatus in such a manner that titanium is evaporated in a constant amount per unit time; forming an Au—TiN mixture gradient coating film whose Au atom content has a gradient in the thickness direction on the TiN coating film by evaporating either gold or gold and another metal in such a manner that the evaporation amount of gold per unit time is increased with time, while evaporating titanium in the dry plating apparatus in such a manner that titanium is evaporated in a constant amount per unit time and the nitrogen amount is kept constant in the dry plating apparatus; forming an Au—TiN mixture coating film on the Au—TiN mixture gradient coating film by evaporating either titanium and gold, or titanium, gold and another metal in the dry plating apparatus in such a manner that either titanium and gold, or titanium, gold and the another metal are evaporated in a constant amount per unit time while the nitrogen amount is kept constant in the dry plating apparatus; and wherein the total thickness of the Au—TiN mixture gradient coating film and the Au—TiN mixture coating film is in the range of 0.005 to 0.1 μm and the thickness of the Au—TiN mixture gradient coating film accounts for 10 to 90% of the total thickness.