Wear and impact behaviour of High Velocity Air-Fuel sprayed Fe–Cr–Ni–B–C alloy coatings. (March 2016) - Bolelli, Giovanni
Abstract: The tribological properties of High Velocity Air-Fuel sprayed Fe–31Cr–12Ni–3.6B–0.6C (wt%) coatings are studied as a function of the deposition parameters. At room temperature, ball-on-disk sliding against Al2 O3 is controlled by abrasive grooving and interlamellar cracking, with some tribo-oxidation. Interlamellar crack propagation also controls the coatings response to cavitation erosion and cyclic impact tests. Coatings deposited with higher powder feed rate exhibit poorer performance under all conditions, because of weaker interlamellar cohesion. At 700 °C, sliding wear rates are levelled out, and they are one order of magnitude higher than at room temperature, because of severe abrasive grooving. Graphical abstract: Highlights: Sliding wear at room temperature depends on abrasion and brittle fracture. Cavitation proceeds by interlamellar cracking, starting after an incubation of 60 min. The cavitation resistance of the coatings compares favourably to that of bulk Ni–30Cu. Inclusion of unmelted particles in the coatings facilitates cyclic impact cracking. Sliding wear at 700 °C involves severe abrasion, and all performances are levelled.