The structure evolution of austenite stainless steel with pre-shot peening during plasma nitriding

Abstract

Austenitic stainless steel is a very promising metal bipolar plate for proton exchange membrane fuel cells (PEMFC), which has advantages such as high mechanical strength, easy processing, and low cost. However, it is prone to corrosion in the acidic environment of PEMFC, which can have adverse effects on its lifespan and conductivity. By adopting a composite modification method to generate a dense nitride structure on the surface of 304 stainless steel bipolar plates, the corrosion resistance of the bipolar plate substrate can be improved. In this paper, shot peening pretreatment and plasma nitriding hybrid modification methods were employed to improve nitriding efficiency and reduce nitriding critical temperature, which generated a modified layer with good corrosion resistance on the surface of 304 austenitic stainless steel.