Influence of atomic and mechanical attrition on low temperature plasma nitriding of ferrous alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 527; no. 13; pp. 3206 - 3209
• Main Authors: Cemin, Felipe, Echeverrigaray, Fernando G., Rovani, Ane C., Amorim, Cintia L.G., Basso, Rodrigo L.O., Baumvol, Israel J.R., Figueroa, Carlos A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.05.2010; Elsevier
• Subjects: Applied sciences; Atomic attrition; Condensed matter: structure, mechanical and thermal properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Hardness; Heat treatment; Materials science; Mechanical attrition; Metals. Metallurgy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Plasma nitriding; Powder metallurgy. Composite materials; Production techniques; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Technology; Thermochemical treatment and diffusion treatment; Mechanical attrition; Plasma nitriding; Atomic attrition; Hardness; Thermochemical treatment; Austenitic stainless steel; Scanning electron microscopy; Potential barrier; Ball mill; Nitrided layer; Nanoindentation; Mechanical properties; Nitriding; Mechanical alloying; X ray diffraction; Layer thickness; Attrition mill; Phase transformation; Oxidation; Pretreatment; Atomic structure; Plasma temperature; Crystalline structure
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2010.02.012

AISI 316 austenitic stainless steel samples were plasma nitrided in variable process times at low temperature (300 °C). Two different pretreatments were performed where ball milling (mechanical attrition) and argon plasma (atomic attrition) were used in order to study their posterior effects on plasma nitriding. X-ray diffraction, scanning electron microscopy and nano-indentation experiments were performed for characterization before and after plasma nitriding. Mechanical attrition produces a phase transformation of the original crystalline structure while atomic attrition creates preferential planes in the same crystalline structure. After plasma nitriding and although both pretreatments increase the hardness, the atomic attrition shows the highest hardness values. The mechanical attrition decreases the nitrided layer thickness due to surface oxidation that creates a potential barrier for nitrogen incorporation.