METROLOGICAL TESTS OF A MICRO-ARC OXIDATION GALVANIC CELL IMPEDANCE

Backgroung. The method of micro-arc oxidation allows to obtain protective coatings on products made of metals of the valve group used in various industries. For the synthesis of coatings with specified properties, it is necessary to perform measurements of their electrophysical parameters with guaranteed accuracy. The object of the study is a measuring converter of the impedance of a galvanic cell and the conductivity of an electrolyte in the process of microarc oxidation. The purpose of the study: to achieve the required accuracy characteristics of the impedance measuring converter by developing a methodology and conducting metrological tests. Materials and methods. Metrological tests of the measuring converter were carried out experimentally using an automated micro-arc oxidation unit «MDOlab», as well as a high-precision LCR meter WK6430B by substitution method. Due to the features of the MDOlab installation software, the measured impedance was converted into the resistance and capacitance of an equivalent parallel RC circuit. For the experiment, model impedance measures were made, expressions for calculating their resistance and capacitance were obtained. A method of metrological tests has been developed, which involves the introduction of a correction factor to eliminate the systematic error of the measuring converter. Results. As a result of the application of the proposed methodology of metrological tests, the systematic error in measuring resistance and capacitance was minimized and amounted to no more than 0.02 %; the main relative error in measuring resistance and capacitance was no more than 0.5 %, which meets the stated requirements. Conclusions. The proposed method of metrological tests allows achieving the required accuracy of measuring the impedance of a galvanic cell, which indicates its effectiveness. The developed measuring converter can be used to study and control the process of micro-arc oxidation and the electrophysical parameters of the synthesized coatings.

Abstract licence: CC BY

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