Increasing the Information Capacity of Materials Non-destructive Electrical Measurements

Abstract

Various methods of material control are considered. It is shown that electrical methods of non-destructive testing of dielectrics, connecting the electrical and mechanical characteristics of materials, have not been sufficiently developed—the process of accumulation and relaxation of electric charges in dielectric materials is long-term. At room temperatures, migration polarization in ionic dielectrics can develop over the years. Therefore, the use of standard measuring bridges of alternating current for measuring capacitance and dielectric constant, tangent of dielectric loss angle, and leakage currents for these purposes is unacceptable. At the same time, measuring instruments for constant electric fields have not been developed enough due to the objective difficulties of direct measurement of these fields. This paper develops an approach to solving this problem, based on the use of low-frequency and static electrical parameters and characteristics as informative for non-destructive quality control. The theoretical foundations for increasing the sensitivity of electrical methods for non-destructive testing of high-resistance materials are presented. In this sense, the frequency and magnitude of the testing signal are analyzed. It was concluded that the most informative is low-frequency measurements on a weak signal. In this case, measurements of the permittivity of ceramic products in the form of a disk were carried out both in the microwave range on an 8-mm interferometer and in a constant electric field. Measurements in a constant electric field demonstrated the best information content and correlation with the ultimate strength in bending of the studied samples.KeywordsNon-destructive testingCeramicsPermittivityElectric fieldElectrical measurements