Investigating Tribological Characteristics of HVOF Sprayed AISI 316 Stainless Steel Coating by Pulsed Plasma Nitriding

Abstract

In this study, surface modification of aluminum alloy using High-Velocity Oxygen Fuel (HVOF) thermal spray and pulsed plasma nitriding processes was investigated. AISI 316 stainless steel coating on 1050 aluminum alloy substrate by HVOF process was pulsed plasma nitrided at 793 K under 0.00025 MPa pressure for 43200 s in a gas mixture of 75 % N-2 and 25 % H-2. The results showed that the pulse plasma nitriding process produced a surface layer with CrN, iron nitrides (Fe3N, Fe4N) and expanded austenite (gamma(N)). The pulsed plasma nitrided HVOF-sprayed coating showed higher surface hardness, lower wear rate and coefficient of friction than the untreated HVOF-sprayed one.