Sliding Wear Investigation of Ni-based Coating for High-Temperature Application

The effect of high temperature on the sliding wear and friction behaviour of NiCrBSiFe powder coating on stainless steel 316L substrate was investigated. The NiCrSiBFe coatings were obtained using a thermal spray technique. The sliding wear tests were performed as per ASTM G99 on the pin on disc tribometer from room temperature (28 °C) to 700 °C temperature condition. The coating characterization was carried out with X-ray diffraction, scanning electron microscopy, porosity analysis and nano-indentation. A 3D non-contact analysis was performed on the wear-track to obtain the wear rate of the coating at different temperatures. The coefficient of friction and wear rate was obtained for the coatings against silicon nitride (1580 HV_0.3) material. The coefficient of friction was obtained as 0.68, 0.15 and 0.51 at room temperature, 300 °C and 700 °C, respectively. The mild wear range confirms the efficacy of the coating at high temperature. The wear rate and coefficient of friction of the coatings were influenced by the oxidation and mechanical properties at the high-temperature conditions. The wear rate increases from 300 °C to 700 °C as the substantial amount of material loss from the coating surface occurred due to the coatings thermal softening and the fragmentation of oxides like CrO3, SiO2 and NiO.