Effects of loads on friction-wear properties of HVOF sprayed NiCrBSi alloy coatings by laser remelting

摘要

A high velocity oxygen fuel (HVOF) sprayed NiCrBSi coatings on H13 hot work mould steel were processed using a laser remelting (LR). The surface-interface morphologies, chemical compositions and phases of the obtained coatings were analyzed using a scanning electronic microscope (SEM), energy dispersive spectroscope (EDS), X-ray diffractometer (XRD), respectively. The friction-wear behaviors of the coatings at high temperatures were investigated using a high temperature wear tester, the effects of loads on the coefficients of frictions (COFs) of the coatings were discussed. The results show that the average COF of the coatings under the loads of 4, 8, and 12 N is 0.34, 0.47, and 0.36, respectively. The coating has excellent wear resistance properties, the wear rates decrease with increasing of the loads. The wear mechanism of the coating is primarily oxidation wear under the load of 4 N, there is a small amount of wear debris on the worn track. While the worn tracks surface under the load of 8 and 12 N appear furrows and spalling pits, the wear mechanism is abrasive wear and oxidation wear. At 600 degrees C, the Ni, Fe and Si of the coating are oxidized, the wear resistance of the coating is improved by the oxides. (C) 2017 Elsevier B.V. All rights reserved.