Issue << content << Metrological Assurance of Noncontact Methods of Coating Thickness Measurement

DOI: 10.12737/article_58dbc95a960d6

2017. Vol.20. 1, pp. 10-13

Metrological Assurance of Noncontact Methods of Coating Thickness Measurement

S. S. Golubev, N. I. Smirnova

Today the thickness is one of the main parameters measured, determining the quality of the coatings. In some cases the measurement of the coating thickness should be performed using a non-contact non-destructive testing: eddy current, infrated thermography, X-ray (radiometric and fluorescent), β-back scattering. However, measuring instruments implementing the above methods can not be traceable to national primary standards, because these methods are indirect and calibration of measuring instruments must be carried out on the coating thickness standards with known stable factors affecting measurement accuracy the analysis of which for measuring tasks are performed.
The regulatory framework of metrological assurance of non-contact methods for measuring coating thickness are analyzed. The analysis showed that in the hierarchy scheme is not following type thickness gauges: dielectric coating on dielectric substrates; ferromagnetic coatings on dielectric substrates.
It is also found that the normative documents on the types and methods of nondestructive testing, which is set to the terms and definitions of the requirements, does not specify requirements for standards and measuring instruments involved in the transfer of units and implementing hierarchy scheme. Propositions for the development of normative documents to the non-contact methods for measuring coating thickness, which will establish the requirements for thickness gauge measures the thickness of coatings and the requirements for their verification and calibration are formulated.
To ensure uniformity of measurement of coating thickness non-contact methods is necessary except to impede the geometric also be sure to control the physical, electrical and thermal parameters measures the thickness for each of the non-contact method at the stages of manufacturing and verification of measuring instruments.
Keywords: thickness, coatings, coating thickness standards, non-contact, eddy-current, infrared thermography, x-ray, measurement.


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