Increasing the Wear Resistance of Heat-Resistant Nickel Alloy Using Anodic Plasma Electrolytic Treatment

A possibility of the plasma electrolytic treatment of a heat-resistant nickel alloy ChN77TiAlB, which leads to the removal of edge cracks, a decrease in hardness, and an increase in wear resistance, is shown. The volt-ampere and volt-temperature characteristics of the plasma electrolytic treatment, typical for anodic processes, are revealed. Changes in the morphology and roughness of the surface and the structure and microhardness of the surface layers are considered. It was established that the treatment in an electrolyte based on carbamide and ammonium chloride leads to the formation of nitrocarburized layers without the formation of compounds. The combined effect of both high-temperature oxidation and anodic dissolution on the morphology and roughness of the surface was determined. Tribological tests were conducted using the ball-on-disk scheme, which showed the best results after treatment at 900°C (reduction in volumetric wear by 15.7 times), when a reduction in roughness (by five times) and the presence of thick oxide layers determine a uniform running-in period, reaching a lower value of the friction coefficient, and homogenization of the alloy, accompanied by the removal of cracks, determines a softer wear mechanism. Positive results were obtained in abrasive wear tests: after treatment at 600 and 900°C, volumetric wear decreased by 2.6 and 2.2 times, respectively.