Friction and wear properties of D-gun sprayed CrFeNiAl0.3Ti0.3-Ag-SrSO4 high entropy alloy matrix self-lubricating coating at elevated temperature

CrFeNiAl0.3Ti0.3-10 wt% Ag-(10-30) wt% SrSO4 high entropy alloy matrix self-lubricating coatings were fabricated using detonation spray technique and tribological characteristics of CrFeNiAl0.3Ti0.3-10 wt% Ag-(10-30) wt% SrSO4 coatings were explored from 25 to 1000 degrees C. The Ag and SrSO4 lubricants have good compatibility with CrFeNiAl0.3Ti0.3 matrix phase. The bond strength and hardness of CrFeNiAl0.3Ti0.3-Ag-SrSO4 coatings are 30 similar to 65 MPa and 461 similar to 535 HV, respectively. Meanwhile this coating exhibited good tribological performance across the wide temperature range and achieved the lowest friction coefficients of 0.29 similar to 0.49 and wear rates of 2.68 similar to 11.82 x 10(-5) mm(3)/Nm when SrSO4 content is 10 wt%. Between 25 and 600 degrees C, SrSO4 and Ag lubricants, can effortlessly create complete lubricating films, preventing three-body wear and plastic deformation. At 800 and 1000 degree celsius, SrSO4 inflicts a significant impact on the formation of the oxide tribo-layer. When SrSO4 content is 10 wt%, it is feasible to form a compacted oxide layer containing SrCrO4, SrAl2O4 and SrTiO3, reducing the friction and wear. With further increasing SrSO4 content to 20 wt% and 30 wt%, the excessive SrSO4 leads to a detrimental on the compactness of oxide tribo-layer, increasing the friction and wear.