Mechanistic study of incipient corrosion for nuclear grade lean-Cr FeCrAl alloys in a simulated PWR environment
Zheng Qu, Chuiyi Meng, Juncheng Huang, Yuchang Mei, Yinmeng Zhang, Jiaojiao Ma, Wenguan Liu, Hui Wang, Xiujie He
Abstract
This study systematically investigated the incipient corrosion behavior of Fe-13Cr-4.5Al (wt%) and lean-Cr (7–10 wt%) with 5Al (wt%) FeCrAl alloy with a timescale of 4 months under simulated PWR conditions (18.6 MPa and 360 °C) in an autoclave system. The corrosion induced two types of structure of oxide scale. FeCrAl alloys corroded for 3 months exhibited a duplex structure containing outer oxide particles and an inner Cr-rich spinel. During the corrosion test lasting 3–4 months, a triplex structure containing outer oxide particles, an inner compact Cr-rich spinel layer, and a porous spinel layer was observed. Moreover, Cr enriched at the periphery of outer oxides, indicating the formation of FeCr2O4 spinel oxide.