BS EN ISO 21968:2019
$189.07
Non-magnetic metallic coatings on metallic and non- metallic basis materials. Measurement of coating thickness. Phase-sensitive eddy-current method
| Published By | Publication Date | Number of Pages |
| BSI | 2019 | 46 |
This document 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:
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zinc, cadmium, copper, tin or chromium on steel;
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copper or silver on composite materials.
The phase-sensitive method can be applied without thickness errors to smaller surface areas and to stronger surface curvatures than the amplitude-sensitive eddy-current method specified in ISOÂ 2360, and is less affected by the magnetic properties of the basis material. However, the phase-sensitive method is more affected by the electrical properties of the coating materials.
In this document, the term â??coatingâ?? is used for materials such as, for example, paints and varnishes, electroplated coatings, enamel coatings, plastic coatings, claddings and powder coatings.
This method 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.
The measurement of metallic coatings on metallic basis material works only when the product of conductivity and permeability (Ï?, μ) of one of the materials is at least a factor of two times the product of conductivity and permeability for the other material. Non-ferromagnetic materials have a relative permeability of one.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | National foreword |
| 4 | European foreword |
| 6 | Foreword |
| 7 | 1 Scope 2 Normative references 3 Terms and definitions |
| 8 | 4 Principle of measurement |
| 11 | 5 Factors affecting measurement uncertainty 5.1 Basic influence of the coating thickness 5.2 Electrical properties of the coating 5.3 Geometry — Base material thickness 5.4 Geometry — Edge effects |
| 12 | 5.5 Geometry — Surface curvature 5.6 Surface roughness 5.7 Lift-off effect |
| 14 | 5.8 Probe pressure 5.9 Probe tilt 5.10 Temperature effects 5.11 Intermediate coatings 5.12 External electromagnetic fields 6 Calibration and adjustment of the instrument 6.1 General |
| 15 | 6.2 Thickness reference standards 6.3 Methods of adjustment |
| 16 | 7 Measurement procedure and evaluation 7.1 General 7.2 Number of measurements and evaluation |
| 17 | 8 Uncertainty of the results 8.1 General remarks 8.2 Uncertainty of the calibration of the instrument |
| 18 | 8.3 Stochastic errors |
| 19 | 8.4 Uncertainties caused by factors summarized in Clause 5 8.5 Combined uncertainty, expanded uncertainty and final result |
| 20 | 9 Precision 9.1 General 9.2 Repeatability (r) |
| 21 | 9.3 Reproducibility limit (R) |
| 23 | 10 Test report |
| 24 | Annex A (informative) Eddy-current generation in a metallic conductor |
| 30 | Annex B (informative) Basics of the determination of the uncertainty of a measurement of the used measurement method corresponding to ISO/IEC Guide 98-3 |
| 32 | Annex C (informative) Basic performance requirements for coating thickness gauges based on the phase-sensitive eddy-current method described in this document |
| 34 | Annex D (informative) Examples for the experimental estimation of factors affecting the measurement accuracy |
| 39 | Annex E (informative) Table of the student factor |
| 40 | Annex F (informative) Example of uncertainty estimation |
| 43 | Annex G (informative) Details on precision |
| 45 | Bibliography |
