On a determination of wear resistance and adhesion of molybdenum, Cr–Ni and Cr–Mn steel coatings thermally sprayed on a 35CrMo4 steel

Abstract This paper aims to show the relationship between, on one hand, the deposition and post-deposition conditions, and on the other hand, the adherence and wear resistance of molybdenum and Cr–Ni–Mn alloyed steel coatings thermally sprayed on a 35CrMo4 steel substrate. The adherence to steel substrate was determined using a four-point “delamination” test bend and the tribological behavior of coatings has been studied using a simple ball-on-plate tribometer. The study has also been focused on the influence of a post-annealing at 850 °C for 1 h in vacuum followed by air cooling on the adherence of the two different coatings on the steel substrate and on their wear resistance under specific wear and lubrication conditions. Flame sprayed molybdenum showed high tribological behavior and strong adhesion in relation with its metallurgical nature and the substrate surface preparation. Post annealing and lubrication are rather beneficial for electric arc sprayed steel coating. The first one improved its adhesion to substrate and the second decreased its friction coefficient against a hardened 100Cr6 steel ball.