Iron boride-based thermal diffusion coatings for tribo-corrosion oil production applications

Engineering components and tubing systems for the down-hole applications in the oil production should withstand severe friction, sliding abrasion and corrosion actions. To resolve wear and corrosion issues, the hard iron boride-based coatings on steels obtained through the thermal diffusion process can be applied on the entire working surfaces of large size and complex shape products. The behavior of these coatings obtained at Endurance Technologies Inc. has been studied in the friction–abrasion, friction–corrosion and friction–abrasion–corrosion conditions simulating oil production service conditions. Tribological studies have been conducted using the “rod-on-flat” reciprocating sliding method in the conditions simulating actual application conditions. The synergistic actions of harsh conditions results in a higher rate of materials destruction. The obtained iron boride coatings demonstrated significantly lower wear losses with no delamination and spalling than untreated steels and Ni- and Cr-based coatings. The encouraging tribo-corrosion test results for boride coatings are explained by their high hardness and chemical inertness, specific structure obtained through the thermal diffusion process with reduced micro-crack propagation and the thin “tribofilm” formed during a friction mode. Successful application of the products with the boride protective coatings is reported.