Abstract
A hybrid plasma surface alloying process has recently been developed for austenitic stainless steels to improve their surface hardness, wear resistance and corrosion resistance. The process is carried out in nitrogen and methane gas mixtures at temperatures below 450°C and facilitates the simultaneous incorporation of nitrogen and carbon into the surfaces of austenitic stainless steels, forming a dual layer structure with an extremely hard nitrogen-enriched layer on top of a hard carbon-enriched layer. The present paper discusses the influence of three most important processing parameters, i.e., gas composition, temperature and time, on the structural characteristics of the alloyed zones produced on AISI 321 stainless steel, in terms of layer morphology, growth kinetics and chromium compound precipitation. It was found that the development of the alloyed layers is diffusion-controlled, and under proper processing conditions, a precipitation-free dual-layer structure can be produced, with nitrogen and carbon dissolved in the relevant layer forming N-expanded austenite and C-expanded austenite respectively. Based on the experimental results, a threshold temperature–time curve has been established for the investigated austenitic stainless steel.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
