Performance of hard coatings, made by balanced and unbalanced magnetron sputtering, for decorative applications

Decorative PVD coatings have been developed to replace the traditional gold plating used for 'high-value' watch industry and jewellery, whose minimum gold thickness was 10 mu m. According to the price of gold in the late 1970s and early 1980s, a number of companies, active in the watch industry or specialising in PVD surface coatings, have worked and tried to replace the gold plating by a yellow TiN PVD coating. Preci-Coat was the first company, worldwide, to succeed and to industrialise the yellow PVD coating for these 'high-value' decorative applications. Various other colours, in addition to the yellow colour, have been developed, such as black, blue, etc. Because of the high price of the final product, great performance of the PVD coatings is requested. Preci-Coat has succeeded in mastering this aspect by improving the different deposition parameters of PVD treatments by sputtering and also by the combination of PVD and electroplating. Some examples of coloured coatings are presented, considering their advantages and drawbacks as well as their chemical and mechanical behaviour towards external environments. (C) 1999 Published by Elsevier Science S.A. All rights reserved.