BS EN ISO 21968:2019

What is ISO 21968- Non-magnetic metallic coatings about? 

ISO 21968 is an International Standard that discusses non-magnetic metallic coatings on metallic and non- metallic basis materials. 

ISO 21968 specifies a method for using phase-sensitive eddy-current instruments for non-destructive measurements of the thickness of non-magnetic metallic coatings on metallic and non-metallic basis materials such as: 

• Zinc, cadmium, copper, tin, or chromium on steel 
• Copper or silver on composite materials 

In ISO 21968, the term “coating” is used for materials such as, for example, paints and varnishes, electroplated coatings, enamel coatings, plastic coatings, claddings, and powder coatings. 

Who is ISO 21968- Non-magnetic metallic coatings for? 

ISO 21968 on phase-sensitive eddy-current method for coating thickness measurement is relevant to: 

• Companies involved with coatings technology  
• Inspection of welding joints, gas turbine blades, metal tubes, etc 
• Aerospace and automotive industry 
• Applications that require heat treat verification of metals 
• Quality control and testing laboratories 

Why should you use ISO 21968- Non-magnetic metallic coatings? 

Phase-sensitive eddy-current instruments work on the principle that a high-frequency electromagnetic field generated by the probe system of the instrument will produce eddy currents in the coating on which the probe is placed and in the base material beneath the coating in case this base material is conductive. 

The method provided in ISO 21968 is particularly applicable to measurements of the thickness of metallic coatings. These coatings can be non-magnetic metallic coatings on non-conductive, conductive or magnetic base materials, but also magnetic coatings on non-conductive or conductive base materials. 

ISO 21968 can accurately help determine thickness of non-magnetic metallic coatings on metallic and non-metallic basis materials, that provides indications on corrosion, abrasion, and chemical resistance properties of the coatings. This can ultimately help you enhance the quality, performance and service-life of the end-use application with robust defect detection practices. 

What’s changed since the last update? 

BS EN ISO 21968:2019 supersedes BS EN ISO 21968:2005, which is withdrawn. BS EN ISO 21968:2019 includes some technical changes with respect to BS EN ISO 21968:2005. These include: 

• ISO 21968 has been adapted to the current requirements of ISO/IEC Guide 983 (also known as “GUM:1995”) 
• Hints, practical examples, and simple estimations of the measurement uncertainty for most important factors have been added 
• repeatability and reproducibility values for typical applications of the method have been added 
• The annex has been expanded with further applications and experimental estimations of factors affecting the accuracy