The Model of the Relationship of the of Micro-arc Oxidation Process Parameters Based on Graph Theory

At present, the micro-arc oxidation technology, which makes it possible to obtain oxide coatings with unique properties on the surface of metals and alloys of the valve group, is increasingly used in science and technology. These coatings are used not only to solve traditional problems, such as protecting machine parts and devices from wear and corrosion, but also when developing new-generation prostheses with antibacterial properties, as well as in dosimetry. The disadvantage of this technology is the lack of controllability caused by a large number of heterogeneous factors that jointly affect the coating properties. To solve this problem, on the basis of graph theory and set theory, a model was developed that describes the totality of the influencing factors of the micro-arc oxidation process and the relationship between them, aimed at finding the most informative factors to be experimentally determined in the coating formation process. The analysis of the developed model showed that the most important technological parameters affecting the properties of the formed oxide layers are forming voltage, time and current density. It is shown that many characteristics of the resulting coatings (micro-hardness, thickness, porosity, wear resistance and thermal conductivity) can be calculated by measuring the time dependences of the voltage (forming curves) and the current of the micro-plasma process or dynamic current-voltage characteristics. The proposed model has a limitation associated with the need to fix a number of technological parameters (temperature, concentration of electrolyte components in the electrolyte, current pulse frequency) when measuring the above dependencies. The model can be used both in scientific research and in production when selecting the optimal technological parameters of the micro-arc oxidation process.