PLATING STRUCTURE AND COATING METHOD

摘要

[Problem] A plating structure which is not sulfurized even by a lapse of time or a temperature rise; a light-emitter support provided with a reflecting surface which has a plating structure with excellent sulfurization resistance; and a coating method for an electric part, capable of forming, on the electric part, a coating that is less susceptible to sulfurization and that has a gloss inherent in silver and a small contact resistance. [Solution] A plating structure obtained by heat-treating a silver-plated structure which is produced by forming a silver deposit layer on a substrate and forming an Sn-Co alloy deposit layer having a thickness of 0.001 to 0.1mum on the surface of the silver deposit layer. A coating method which includes subjecting a particulate deposit of an Sn-Co alloy which is formed on the surface of a silver layer formed on the surface of a substrate to heating in a non-oxidizing atmosphere to melt the particulate deposit and thus form a film. The particulate deposit is composed of deposited particles which are formed by a particle deposition process and which are arranged in a state such that the deposited particles do not overlap each other in the direction perpendicular to the surface and are present with spaces thereamong when viewed from the top. Here, the mean diameter of the deposited particles is 20 to 80nm, while the weight of deposited tin alloy particles per unit area of the surface of the silver layer is 2×10-6 to 8×10-6 g/cm2.