Authors: Anderko, A.¹; Sridhar, N.²; Tormoen, G.³

Source: Corrosion Engineering, Science and Technology, Volume 45, Number 3, June 2010 , pp. 204-223(20)

Publisher: Maney Publishing

Abstract:

A methodology has been developed for predicting the effect of thermal aging on the repassivation potential of austenitic alloys. The methodology combines two models, a grain boundary microchemistry model for calculating the chromium and molybdenum depletion profiles in the vicinity of grain boundaries and an electrochemical model that relates the repassivation potential to the microchemistry and environmental conditions, including temperature and solution chemistry. The grain boundary microchemistry model incorporates a thermodynamic paraequilibrium treatment of the formation of carbides and a kinetic treatment of the diffusion of Cr and Mo. With this model, experimental Cr and Mo depletion profiles can be reproduced for sensitised alloys 600, 825 and 316L. The repassivation potential model accounts for the effects of solution chemistry and temperature by considering competitive dissolution, adsorption and oxide formation processes at the interface between the metal and the occluded site solution. Using a previously developed relationship between the repassivation potential and bulk alloy composition, a procedure has been established for calculating the observable repassivation potential of thermally aged alloys by integrating the local E_rp values that correspond to the alloy microchemistry in the depletion zone. The predicted repassivation potentials agree with experimental data for thermally aged alloys 600 and 825 in chloride solutions. Additionally, the model has been applied to estimate the repassivation potential of welded samples in which segregation of alloying elements is observed.

References: 48 references open in new window

Articles that cite this article?

Keywords: 825 AND 22; LOCALISED CORROSION; REPASSIVATION POTENTIAL; ALLOYS 600; THERMAL AGING

Document Type: Research Article

DOI: http://dx.doi.org/10.1179/174327809X409240

Affiliations: 1: OLI Systems Inc, 108 American Road, Morris Plains, NJ 07950, USA 2: Det Norske Veritas, 5777 Frantz Road, Dublin, OH 43017, USA 3: Southwest Research Institute, Department of Materials Engineering, 6220 Culebra Road, San Antonio, TX 78238, USA

Publication date: 2010-06-01

More about this publication?

• Authors wishing to cite fast track papers should give the journal name and the article DOI. This will enable reference linking via CrossRef and allow forward and backward citation tracking systems to associate the fast track citation with the final journal reference.

  This journal features top 10 articles which are freely available. Please click here and click on the 'Top articles' link in the right-hand menu to view the list and start downloading.

• Editorial Board
• Information for Authors
• Subscribe to this Title
• Terms & Conditions
• Online submission site
• Top 10 Articles
• ingentaconnect is not responsible for the content or availability of external websites

Related content

• In this: publication
• By this: publisher
• In this Subject: Mining & Metallurgy
• By this author: Anderko, A. ;  Sridhar, N. ;  Tormoen, G.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers