ISO specifies a method for non-destructive measurements of the thickness of non-conductive coatings on non-magnetic electrically conductive base. ISO – Non-conductive coatings on non-magnetic electrically conductive basis materials — Measurement of coating thickness — Amplitude-sensitive. N tvnovellas.info Sem Casa de Maquinas Joymore -CR-Engetax. E4 WP6 Brochure. resistencia. a Catalogo Tecnico Gravia.
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ISO. Third edition. Non-conductive coatings on Details of the software products used to create this PDF file can be found in the General Info. de revêtement — Méthode par courants de Foucault sensible aux variations d' amplitude. STANDARD. ISO. Fourth edition. Reference number. ISO Non-conductive coatings on non- magnetic electrically conductive base Fourth edition. Reference number. ISO (E). This is a free 6 page sample. Access the full full version online. ISO - PDF.
English scope ISO specifies a method for non-destructive measurements of the thickness of non-conductive coatings on non-magnetic electrically conductive base metals, using amplitude-sensitive eddy-current instruments. In ISO , the term "coating" 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 most oxide coatings produced by anodizing, but is not applicable to all conversion coatings, some of which are too thin to be measured by this method see Clause 6. This method can also be used to measure non-magnetic metallic coatings on non-conductive base materials. However, the phase-sensitive eddy-current method specified in ISO is particularly usable to this application and can provide thickness results with a higher accuracy see Annex A. This method is not applicable to measure non-magnetic metallic coatings on conductive base metals. The phase-sensitive eddy-current method specified in ISO is particularly useful for this application.
Lift-off can be produced unintentionally due to the presence of small particles between probe and coating. The probe tip shall frequently be checked for cleanliness. The influence of the probe pressure is more pronounced in case of soft coatings because the probe tip can be indented into the coating. Therfore the probe pressure should be as small as possible. Most commercially available instruments are equipped with spring loaded probes ensuring a constant pressure during the placement.
A suitable auxiliary device should be used in case that the probe is not spring loaded. NOTE 1 The contact pressure and the probe tip indentation depth can be reduced by reducing the applied load force or by using a probe with a larger diameter of the probe tip.
NOTE 2 An indentation of the probe tip into soft coatings can be reduced by placing a protective foil with known thickness onto the coated surface. In this case the coating thickness is the measured thickness minus the foil thickness.
The risk of inadvertent tilt can be minimised by probe design or by the use of a probe holding jig. NOTE Most commercially available instruments are equipped with spring loaded probes which ensure a perpendicular placement on the sample surface. Note 1 The influence of temperature variations can be reduced by a temperature compensation of the probe. Note 2 Temperature differences between probe, electronics of the instrument, environment and sample can cause strong thickness errors.
One example is the thickness measurement of hot coatings. In case of unexpected results or a strong variation of results, which cannot be explained by other factors, this reason should be taken into account.
In this situation a comparison measurement should be carried out at a location without interfering fields. Material, geometry, and surface properties of the base metal used for calibration or adjustment should comply with the test specimens in order to avoid deviations caused by the factors described in clause 5.
Otherwise these influences must be considered in the estimation of the measurement uncertainty.
During calibration or adjustment the instruments, the standards and the base metal should have the same temperature as the test specimens to minimize temperature induced differences.
In order to avoid the influence of instrument drifts periodic control measurements with reference standards or control samples are recommended. If required, the instrument has to be re-adjusted.
NOTE Most instruments automatically adjust themselves during a function called "calibration", which is often not obvious to the operator. Foils and coatings must be non-magnetizable. Thickness values of the reference standards and their associated uncertainties must be known and unambiguously documented.
The surface area for which these values are valid must be marked. The thickness values should be traceable to certified reference standards. NOTE 1 The uncertainties shall be documented with their confidence level, e.
Prior to use foils and coatings are to be checked visually for damage or mechanical wear as this would cause a wrong adjustment and thus systematic deviation of all measurement values. NOTE 2 In most cases the foil material is plastics, but other materials, e.
The use of foils compared to selected coated base metals as reference standards benefits from the possibility to place the foils directly on each base metal thus matching each respective shape geometry exactly.
However, by placing the probe on foils elastic or plastic deformation may occur which can affect the measuring result. Moreover, any gap between the pole of the probe, foil and base metal has to be avoided. However, the phase-sensitive eddy-current method specified in ISO is particularly usable to this application and can provide thickness results with a higher accuracy see Annex A. This method is not applicable to measure non-magnetic metallic coatings on conductive base metals.
The phase-sensitive eddy-current method specified in ISO is particularly useful for this application. However, in the special case of very thin coatings with a very small conductivity, the amplitude-sensitive eddy-current method can also be used for this application see Annex A.
Although the method can be used for measurements of the thickness of coatings on magnetic base metals, its use for this application is not recommended. In such cases, the magnetic method specified in ISO can be used.
Only in case of very thick coatings above approximately 1 mm, the amplitude-sensitive eddy-current method can also be used for this application see Annex A.
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