Metallic coatings - Determination of porosity in gold coatings on metal substrates - Nitric acid vapour test

2Scope / Description

This International Standard specifies the test equipment and a method for determining porosity using nitric acid vapor in gold coatings, particularly electrodeposits and plating, for electrical contacts. This method is intended to show whether the porosity is less or greater than a value that the user considers to be permissible based on experience for the intended use. It is suitable for inlays or plating that contain at least 75% gold, for electroplating that contains more than 95% gold, or for base materials made of copper, nickel and their alloys that are commonly used for electrical contacts. Nitric acid vapor testing is too rigorous for gold plating thicknesses less than 0.6 µm. In addition, this test is unsuitable for metallic coatings that are less precious than gold or platinum, e.g. B. palladium and its alloys or partially gold-plated palladium and its alloys. Several other porosity testing methods are described in ISO 10308 and the literature.