Application of metallization coatings for protection of submersible electric motors of pumping equipment from influence of complicating factors in oil wells

The paper provides a review of results obtained when using metallization coatings to protect the outer surface of electric centrifugal pump (ECP) equipment against the complicating factors in oil wells. Metallization coating is applied by thermal spraying using the method selected based on the chemical composition, materials used and properties of the finished coating. The most common coatings on the Russian market are Monel and alloys based on austenitic stainless steel applied by methods of electric arc metallization or high-speed spraying. Traditional coatings obtained by thermal spraying feature by insufficiently high level of physical, mechanical and chemical properties. The studies of failed cases of submersible motors show that most critical shortcomings of the coatings used include insufficient resistance to mechanical impact and abrasive wear, higher electrochemical potential in relation to the base metal, application technology violations, and significant coating porosity. One of the main reasons for the observed shortcomings is the limited number of traditionally used methods and materials. In order to solve the problem of using protective coatings for submersible motors, significantly improve their properties, service life and economic efficiency, it is necessary to use modern achievements of science in the development of coatings to protect metal surfaces from wear and corrosion, namely: to expand the number of methods and materials for coating application; to develop a methodology for coating quality assessment; to develop a methodology for assessing the economic efficiency of protective coatings. Solving these tasks will enable a reasonable technical and economic choice of a specific submersible motor coating for specific operating conditions.