Corrosion Behavior of Inconel 690 & 693 in an Iron Phosphate Melt

Abstract

The corrosion resistance of Tnconel 690 and 693 coupons submerged in an iron phosphate melt has been investigated. After 155 days in an iron phosphate melt at 1050°C, which contained 30wt% of a simulated low activity waste (LAW at Hanford), the weight loss of Inconel 690 and 693 was 14% and 8%, respectively. The overall corrosion rate, calculated from the initial and final dimensions of each coupon, was 1.3 and 0.7 μm/day for the Inconel 690 and 693, respectively. Scanning electron microscopy and X-ray diffraction of the submerged Inconel coupons after 155 days in the iron phosphate melt showed that an altered surface layer had formed which was depleted in nickel and consisted of a (Fe, Cr)2O3 solid solution. This altered layer appears to be chemically protective as indicated by the gradual reduction in weight loss which occurred with time in the iron phosphate melt. Inconel 693 appears to be a better candidate to use as an electrode in iron phosphate melts since its corrosion rate and weight loss was only about one half that of Inconel 690.

Department(s)

Nuclear Engineering and Radiation Science

Second Department

Materials Science and Engineering

Keywords and Phrases

Computer simulation; Corrosion resistance; Scanning electron microscopy; Solid solutions; Corrosion behavior; Inconel 690; Weight loss; Iron compounds

International Standard Serial Number (ISSN)

0022-3115

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2005 Elsevier, All rights reserved.

Publication Date

01 Jan 2005

Link to Full Text

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