Wear Resistance and Abrasive Wear Mechanism of the Metal-Sprayed Coatings Used to Protect SEM

The state of the art of the oil industry in the Russian Federation is characterized by complicated conditions of field development, which is due to a low production rate because of the high viscosity of oil, high aggressiveness, and water-cut media. Almost the entire well stock is operated by a mechanized method, mainly using electric submersible pumps (ESPs). To date, the use of metal-sprayed coatings, which have high physical, mechanical, and chemical properties, is the most effective method to protect submersible equipment in the mining industry, in particular, the submersible electric motor (SEM) body, from the action of complicating factors. Nevertheless, the failure-free service life of equipment often decreases because of the destruction of metal-sprayed coatings. Abrasive wear is one of the most common causes of the destruction of the metal-sprayed coatings of SEM bodies during operation. In this work, we review the main parameters determining the wear resistance of metal-sprayed coatings and consider the main wear mechanisms and the main types of coating failure during wear. The wear resistances of the metal-sprayed coatings deposited by electric arc spraying (EAS) and high-speed flame spraying (HSFS) are studied and compared under the action of abrasive particles. The metal-sprayed coatings are found to fail mainly via the spallation of particles. The metal-sprayed coatings containing refractory compounds are also characterized by fatigue failure caused by the accumulation of internal stresses during high-cycle elastoplastic deformation of the coatings: they facilitate the formation of fatigue cracks and subsequent separation of particles from the surface layer. The results obtained confirm the significant influence of the structural homogeneity of the metal-sprayed coatings on their wear resistance and the fact that the wear process has several stages.