FIELD: measurement.
SUBSTANCE: invention relates to measurement equipment, in particular to methods for detection and evaluation of defects of dielectric and magnetodielectric materials and coatings and can be used in quality control of hard materials and coatings on metal during development and operation of radar absorbent materials and coatings, as well as in chemical, paint and other industries. Microwave method of detecting inhomogeneities in dielectric coatings on a metal substrate involves generating an electromagnetic field of a slow surface E-wave in a dielectric coating in a single-mode mode, measuring its normal to the dielectric-metal surface of its attenuation coefficient, detecting the coating detachment from the threshold value of the attenuation coefficient of the reference sample of the coating and calculating its value. Additionally, surface electromagnetic waves of E-type are excited successively at L-wavelengths, L > N, N is number of layers of coating, measuring the experimental attenuation coefficient of each surface electromagnetic wave, based on a priori known vector of dielectric permeabilities and thicknesses of layers of the analysed multilayer coating and unknown vector of trial values of height of possible defects, L-dispersion parametric equations are calculated, each of which enables to find theoretical value of attenuation coefficient at setting of trial height of possible defects. Based on experimental values of attenuation coefficients and theoretical values obtained when solving dispersion parametric equations, residual functional is made, minimization of discrepancy functional by variation of trial values of height of possible defects from given range of their variation. Values of trial heights of possible defects at which the discrepancy functional receives the minimum value are compared to the zero value. Based on the comparison results, a conclusion is made on the presence or absence of a defect between the layers of the coating, the height of each detected defect is taken as its trial value obtained with minimization of the residual function.
EFFECT: technical result is high probability of detecting defects, as well as accuracy and reliability of estimating values of their height and position relative to layers of multilayer dielectric coating.
1 cl, 3 dwg
