Increase of wear resistance of movable joints working in corrosive-active media with abrasive

Micro-arc oxidizing (MAO) is one of the surface hardening methods of Al. alloys, which allows to build up principally new coatings of high quality with strong adhesion to the base metal and with improved wear resistance. Ceramic layer of Al2O3 is formed under electrochemical oxidation of the outer surface of machined part, immersed into electrolyte (KOH solution) and subjected to asymmetric AC voltage of industrial frequency. Coating thickness on the surface of D16T alloy achieves 0.3...0.4 mm, hardness - 1800...2000 HV. Friction and wear studies were performed using block and roller testing assembly under various lubricating conditions. Coefficient of friction in clay-based drilling mud was equal to 0.045 for MAO samples and 0.19 for reference steel samples; mass loss was 37× 10-4 and 347× 10-4 respectively. Friction joints operation pressures range cam be increased and service life improved by MAO technology.