Physicomechanical Properties of Coatings Based on Max Ti2AlC and (Ti, Nb)2AlC Phases at 20°C and 500°C

Physicomechanical characteristics of 15Kh16k5N2MVFAB-Sh steel (0.15C-16Cr-5Co-2Ni-0.7V-0.6Mo-0.3Nb-0.4N): wear resistance at 20 degrees C and 500 degrees C and resistance to fretting fatigue at 20 degrees C without and with coatings obtained by the method of vacuum-arc deposition using targets based on the MAX phases of Ti2AlC and (Ti1-xNbx)2AlC, where x = 0.1 and 0.2, are investigated. At 20 degrees C the friction coefficient and the wear specific rate of all coatings are greater than that of the studied steel in contact with a ShKh15 steel (1.0C-1.5Cr-0.3Ni-0.3Mn-0.3Si-0.25Cu) ball under a load of 2 N. Unambiguous relationship between microhardness and tribological characteristics of materials has not been recorded. The resistance to fretting fatigue of the samples with Ti2AlC -based coating in contact with the Ni-alloy (17Cr-12W-11Fe-6Co-3Ti-1.5Nb-1.6Al) in high-cycle region (N > 10(5) cycles) is significantly higher than that of uncoated samples. The tribological characteristics of all materials decrease at 500 degrees C but the least for samples with Ti2AlC based coating. We have not found positive influence of niobium doping on the wear and fretting fatigue resistance of these coatings.