Effect of W on corrosion behavior of low alloy steel in wet/dry environment

Toshiyasu Nishimura, Kazuhiko Noda, Toshiaki Kodama

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The chemical state of the tungsten (W) in the rust of low alloy steel was analyzed by EPMA and XPS, and the electrochemical behavior of rust was investigated by alternating current (AC) impedance method after wet/dry cyclic corrosion test with chlorides. The 1.0 mass%W- bearing steel showed higher corrosion resistance than carbon steel in the corrosion test. EPMA and XPS showed that the tungsten existed as WO4 compounds in the rust of W-bearing steel. A Fe-W binary potential-pH diagram was made to investigate the thermodynamic stability of Fe-W oxides, and this showed that WO4 was stable in the rust, which confirmed the physical analysis. An AC impedance measurement was made to obtain the corrosion reaction resistance (Rt) of the rust, and it was found that Rt of W-bearing steel was much larger than that of carbon steel. The corrosion of the W-bearing steel is suppressed by (1) the insoluble FeWO4 formed near the base metal suppressing the anodic reaction, (2) the WO42- ions in the rust changing the selective permeability to prevent the transport of Cl- ions.

Original languageEnglish
Pages (from-to)734-738
Number of pages5
JournalZairyo to Kankyo/ Corrosion Engineering
Volume49
Issue number12
DOIs
Publication statusPublished - 2000 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrochemistry
  • Materials Chemistry

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