Tribotechnical Characteristics of Coatings Based on Bronze BRA7N6F after Melting by a Fiber Laser

Abstract—

The tribotechnical characteristics of coatings based on bronze BrA7H6F after melting with a fiber laser have been studied. Changes of instant friction coefficient, temperature in the friction zone, and wear intensity depending on technology and conditions of coating deposition are considered. Research was carried out on an A-135 tribotester under the scheme of a roller–cradle under the conditions of concentrated contact and high loads. Analysis of wear character and friction surface topography was carried out by electronic microstamping methods. Laser melting provided increase in wear resistance of coatings by 1.5–2 times in comparison with plasma spraying; wear of rubbing surface of coatings increases by 1.3–5 times at an increase of force of loading by 2 times. It is shown that in cases of plasma spraying and laser melting with high energy density of the laser beam on the friction surface the sponge-capillary effect occurs. In conditions of low energy density, the mentioned effect disappears, and plastic flow and adhesive bonding of bronze with the counter-body material (hardened steel 45) is observed on the worn surface.