Phase-sensitive eddy-current method of metallic coating thickness measurement - On question of calibration and verification of coating thickness gauges and metallic coating thickness standards

摘要

The international standardISO 21968:2005《Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method》 was approved in 2005. However, to ensure the required reliability of measurement results of metallic coatings by this method, it is necessary to develop and approve two more standards: 《Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method. Part 2. Verification and calibration of the metallic coating thickness gauges》 and 《Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method. Part 3. Calibration of metallic coating thickness standards》. The following fundamental questions for the standards development are analysed with use of developed models of phase-sensitive eddy-current transducers: the principles of metallic coating thickness standards completion and also influence of their basic electro-physical and geometrical parameters on measurement results. Based on this, suggestions on set, design and basic geometrical and electro-physical parameters of the metallic coating thickness standard, methods of their manufacture and calibration are given in the work. The calculation techniques of results uncertainty during measurements, the calibration of gauges, the calibration and the verification of metallic coating thickness standards and also structure of the standards (part 2 and part 3) and structure of the metrological chain for the definition and dissemination of metal coating thickness measurements are analysed.