Title: Ion nitriding and nitrocarburising of stainless steels and its influence in the corrosion resistance

Authors: L.C. Casteletti, A. Lombardi Neto, A.M. De Oliveira, G.E. Totten

Addresses: Escola de Engenharia de Sao Carlos-USP, Av. Trabalhador Saocarlense 400, 13566 590 Sao Carlos-SP, Brazil. ' Escola de Engenharia de Sao Carlos-USP, Av. Trabalhador Saocarlense 400, 13566 590 Sao Carlos-SP, Brazil. ' CEFET, Av. Getulio Vargas 04, 650256001 Sao Luis- MA, Brazil. ' Department of Mechanical and Materials Engineering, Portland State University, P.O. Box 751, Portland OR 97207-0751, USA

Abstract: The objective of this work was to determine the most appropriate temperatures for ion nitriding and nitrocarburising of AISI 316L austenitic stainless steel and ASTM A 890 Gr 5A super-duplex stainless steel, respectively, and to determine its influence on the corrosion resistance of these steels. Samples of steels were treated at 400 C, 450°C and 500°C and characterised by optical microscopy, X-rays diffraction and corrosion tests. Layer thickness increased with the treatment temperature for both steels. Potentiodynamic corrosion tests showed that for both steels, the nitrided and nitrocarburised layers at 400°C yielded either similar or superior corrosion behaviours when compared to the substrate, which is due to austenite or expanded ferrite presence (S phase).

Keywords: ion nitriding; nitrocarburising; stainless steel; corrosion resistance; AISI 316L; ASTM A 890; S phase; hardness; low temperature nitriding.

DOI: 10.1504/IJMMP.2009.031395

International Journal of Microstructure and Materials Properties, 2009 Vol.4 No.4, pp.399 - 411

Published online: 02 Feb 2010 *

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