Alloys are impurities or mixture of two or more metal compounds. ISO 3160-2 aims to specify coating characterization methods to qualify their corrosion resistance and their adhesion to the substrate concerning esthetical and technical aspects, and to specify methods to determine thickness and gold fineness of these coatings to check that they satisfy the requirements of ISO 3160-1. ISO 3160-2 specifies methods to determine fineness, thickness, corrosion resistance and adhesion for gold alloy coverings on watch-cases and accessories, including bracelets when they are permanently attached to the case. The tests apply only to significant surfaces. ISO 3160-2 applies to all gold alloy coverings specified in ISO 3160-1.
ISO 3160-2 guidelines on gold alloy coverings of watch cases is useful for:
Gold alloy coatings deposited on watch-cases and their accessories have to comply with technical, decorative requirements and have to also satisfy national rules about precious metals. In the context of ISO 3160-2, the term “corrosion” includes tarnishing and oxidation, as well as surface penetration and the effects of the penetration of corrosive agents into porosity and micro-discontinuities of the protection.
It is generally required that, except where specified to the contrary, gold-alloy-covered surfaces should not have suffered any damage after each of the proposed tests. ISO 3160-2 mentions that, if the fineness is measured on a gold alloy covering which is separated from the base metal, the method used to separate the gold alloy covering from the base metal shall not affect the fineness of the gold covering to a significant extent. Adopting ISO 3160-2 will help you in identifying the fineness of the gold alloy.
ISO 3160-2:2015