Studies on tribological behaviour of NiMoAl based self lubricating coatings

Abstract

The NiMoAl-based coatings containing solid lubricants (Ag, WS2, and hBN) have been deposited on Inconel 718 substrate by atmospheric plasma spray technique. The tribological performance of deposited coatings has been evaluated at different temperatures (room temperature, 200, 400, 600 and 800°C) by carrying out sliding wear tests at a constant load of 5 N and sliding speed of 0.35 m/s on a high-temperature ball-on-disk tribometer using alumina ball as counterpart. The primary aim of the study is to examine the possibility of occurrence of synergistic action between a combination of solid lubricants i.e., Ag-hBN, and Ag-WS2; Ag, WS2 and hBN in realizing low friction and wear over the entire range of temperature from RT to 800°C. The study has been divided into two parts based on the addition of solid lubricants: (i) high-temperature tribological behavior of the NiMoAl, NiMoAl-10 wt. % Ag, NiMoAl-10 wt. % WS2, and NiMoAl-5 wt. % Ag-5 wt. % WS2 composite coatings, and (ii) elevated temperature tribological characteristics of NiMoAl, NiMoAl-10 wt. % Ag, NiMoAl-10 wt. % hBN, and NiMoAl-5 wt. % Ag-5 wt. % hBN coatings. newline