Reducing equipment parts biocorrosion operated in underground minings due to the detonation Ti-Cu spraying application
Authors:   Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences, Ulyana Ulyana , Egorkin Vladimir ,   Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences, Sirota Viacheslav ,   Belgorod State Technological University Named After V.G. Shukhov, Zaitsev Sergey ,   Belgorod State Technological University Named After V.G. Shukhov
Published: May 2024

Introduction. The wide distribution of microorganisms in the natural and technogenic environment, in the conditions of underground mine workings, is explained by their phenomenal adaptation capabilities. The high activity of microorganisms at significant depths under extreme conditions is due to the peculiarities of their metabolism. The maximum number of these factors is typical for underground mining. The lithosphere, in which underground structures are built to ensure the development of deposits, in addition to its well-known characteristics, is also a habitat for microorganisms. The waste products of these microorganisms significantly influence the rate of corrosion of metals. Often the scale and speed of bio damage are so significant. Therefore, the study of microbial bio damage processes and their prevention under these conditions is an extremely urgent task. Materials and methods. The corrosion rate in an aggressive biological environment of three types of samples was studied. The first type of samples were ordinary plates made of St 3. The second type of samples was the same St 3 but with antimicrobial enamel XC-5286 applied to the surface. And the third type of samples were samples made of St 3 with a detonation coating applied to their surface from a mixture of Ti (PTN-8VT10) and Cu (PMS-1) powders. These samples were exposed to a biologically active corrosive environment for one month. Then the level of damage and corrosion development on the surface of the samples was measured. Results. The results of the study showed that the use of the method of detonation thermal spraying makes it possible to form a protective Ti-Cu composite coating with anti-corrosion properties on the surface of low-carbon steel. The rate of biological corrosion of steel samples with Ti-Cu coating is 40% less than on control samples without such a coating. The anti-corrosion efficiency of the XC-5286 coating was 80%. Discussion. The antimicrobial effectiveness of Cu ions primarily depends on their concentration adjacent to the coating surface, which in turn is determined by the rate of release of biocide ions. When immersed in an aqueous solution, copper (I) oxide (Cu2O), which is part of both the XC-5286 coating and the Ti-Cu composite coating formed by thermal spraying, is unstable and, under the influence of chlorine, hydrogen and oxygen ions, quickly oxidizes to more stable divalent copper ions Cu2+. To maintain the required level of antimicrobial effect, the average rate of release of copper ions from contact-type coatings (which includes XC-5286) must be at least 50 μg/cm2 day. The rate of release of Cu ions from a composite Cu-Ti coating formed by plasma spraying is about 20.5 μg/cm2 day, which is almost 2 times less than the required level. This explains the lower antimicrobial efficiency (AE) of Ti-Cu composite coatings compared to XC-5286 enamel, which has an AE value of 80.5%. As shown by full-scale tests, even at low values of the release rate of Cu ions, the coating under study provides effective inhibition of the development of bio corrosion. Conclusions. The work established that the use of the method of detonation thermal spraying made it possible to form a protective Ti-Cu composite coating with anti-corrosion properties on the surface of low-carbon steel. Resume. The work established that the use of the method of detonation thermal spraying made it possible to form a protective Ti-Cu composite coating with anti-corrosion properties on the surface of low-carbon steel. Such Ti-Cu-based coatings can be used not only to protect mechanisms, structural elements and structures operating in mining conditions, but also for their operation in humid climates subject to periodic wetness.