Method for Measuring the Oxide Coating Thickness in the Micro-arc Oxidation Process

The article describes a method for measuring the thickness of protective coatings obtained by micro-arc oxidation (MAO) using the transformation "coating thickness–pulse frequency". A scheme for measuring the coatings thickness and the structure and operation principle of a frequency integrating scanning converter (FISC) developed by the article authors, which is the main node of the measuring channels are described. FISC is made on three operational amplifiers, but can be produced in the form of a microcircuit. A metrological analysis of the measuring channel of the thickness of MAO-coatings was carried out, the thickness–inverse capacitance and capacitance– pulse frequency conversion functions were obtained, and errors measurement were calculated in the work.