Controlled Synthesis of Multifunctional Coatings by Micro-Arc Oxidation Method

Background

A large number of theoretical (Clyne & Troughton, 2019; Ao et al., 2020) and experimental studies (Wang et al., 2020; Bordbar-Khiabani et al., 2019) have been devoted to the study of a promising area of surface treatment of light metals and alloys (aluminum, magnesium, titanium, etc.) under the name micro-arc oxidation. This is due to the fact that the ceramic oxide coatings obtained by this method have improved performance characteristics: micro-hardness, wear resistance (Haghighat-Shishavan et al., 2019), corrosion resistance (Buling & Zerrer, 2019), biocompatibility (Nabavi & Aliofkhazraei, 2019), magnetic (Rudnev et al., 2020), and antifouling properties (Zhang et al., 2020). In addition to the traditional fields of this technology application (mechanical engineering, the aerospace, rocket and space industries, prosthetics in medicine), new ones (dosimetry (Zolotarjovs et al., 2019), production of ferroelectric ceramics (Teng & Lu F.-H., 2020)) appear or existing ones (prostheses with antibacterial properties (Santos et al., 2019)) expand, which in the long term can lead to great demand for products with such coatings among citizens not only of Russia but also of other countries.

It should be noted, however, that in order to successfully obtain multifunctional coatings by the micro-arc oxidation method on an industrial scale, optimal technological conditions must be developed to guarantee high quality of the finished product at the minimum cost of its production, which is associated with some difficulties. Firstly, this is a large number of heterogeneous factors that simultaneously affect the properties of the formed oxide layer (Golubkov, Pecherskaya, Shepeleva et al., 2018); secondly, the variety of possible directions of use, for which the requirements for the properties of the finished coating can vary widely; thirdly, insufficient knowledge of the MAO process, the lack of an analytical description of a number of interconnections between influencing factors; and fourthly, the imperfection of technological and measuring equipment, the inability to control and register the oxide layers properties in the process of their formation. All this greatly complicates the development of the technological process and leads to the need to create an automated system that realizes the production of MAO coatings with the required properties.

Currently, works of this kind are being conducted both in Russia (Bolshenko et al., 2014) and abroad (Progress industrial systems SA, 2012; Plasma Technology Ltd., n.d.), however, these systems have limited control capabilities, as they do not allow measuring the properties of MAO coatings during their formation. In (Golubkov, Pecherskaya, Karpanin et al., 2017), the concept of an intelligent automated system for the controlled synthesis of MAO coatings was proposed but theoretical positions on which the intelligent application of controlled synthesis is based, as well as methods for choosing the optimal technological mode, were not considered. This article proposes theoretical models that make up the methodology for the controlled synthesis of oxide coatings, and also presents the structure and functioning algorithm of an intelligent automated micro-arc oxidation system.