METHOD TO PRODUCE GOLDEN BRONZE BY DIFFUSION OF TIN INTO COPPER UNDER CONTROLLED CONDITIONS

摘要

The present invention relates to the production of a bronze plated substrate having a golden appearance thanks to a multiple-layer plating method. The method notably comprises plating a substrate having at least one layer of copper with a tin layer which thickness represents 3.5 % to 12% of the copper layer thickness. The method further comprises annealing the plated substrate in an annealing furnace comprising a plurality of heating zones, the last heating zone of the furnace having an annealing temperature ranging from 600°C to 815°C. The annealing step of the method is performed under controlled operating parameters which comprise an annealing residence time, the annealing temperature and the relative thickness of the tin layer in view of the copper layer. The operating parameters are controlled in accordance to each other to ensure obtaining the gold-like appearance of the plated bronze.