1094.ジルコニウム合金の均一腐食および水素吸収に及ぼす析出物の電気化学的役割,(I)

Abstract

Substantial roles of precipitates such as Zr-Fe-Cr type intermetallic compounds on uniform corrosion and hydrogen pickup of zirconium alloys in pure water autoclave tests were investigated from an electrochemical point of view. This paper describes the roles on corrosion. A corrosion test on precipitate-containing and precipitate-free materials made from pure zirconium and a small quantity of iron and chromium, rest potential measurements on an intermetallic compound of Zr(FeCr)2 and zirconium matrix, and a galvanic coupling test of those were performed. Results showed that corrosion behavior of zirconium alloys could be attributed to the electrochemical properties of intermetallic compounds precipitated in each alloy. Namely, the cathodic and anodic polarization characteristics were associated with anodic protection provided by the precipitates on the alloys and the precipitates degradation in the oxide films, respectively. The mechanism was confirmed through a corrosion test of Zr-X(X=0.2Fe, 0.2Cr, 0.1Fe-0.1Cr) alloys and electrochemical measurements of ZrFe2, ZrCr2, and Zr(FeCr)2 intermetallic compounds.