铁素体-马氏体钢P92在超临界水中的腐蚀性能

研究了P92钢在550和600℃超临界水中的腐蚀特性，采用扫描电镜、X射线能谱仪和X射线衍射仪分析了氧化膜的表面形貌、组织结构和元素分布。结果表明：P92钢在超临界水中的氧化动力学大致服从立方生长规律，600℃下P92钢的腐蚀增重和氧化膜厚度均为550℃时的3倍。P92钢在超临界水中形成的氧化膜为双层结构，氧化膜外层富Fe，而内层富Cr。600℃时P92钢氧化膜发生了开裂和剥落，其原因主要在于降温过程中基体与氧化物间的热膨胀系数不相匹配而产生的较大热应力。

Corrosion Behavior of Ferritic-Martensitic Steel P92 in Supercritical Water

The corrosion behavior of P92 steel was investigated in supercritical water at 550 and 600 ℃ with SEM, EDS and XRD as to analysis the oxide morphology, structure and element distribution. The results show that oxidation of P92 steel approximately follows cubic growth kinetics in supercritical water, and the weight gain as well as oxide scale depth at 600 ℃are both as three times as than those at 550 ℃. A dual-layer structure was identified in the oxide scale. The outer layer is rich in Fe, while the inner layer is rich in Cr. The cracking and spalling of oxide film on P92 steel at 600 ℃is mainly ascribed to the largerthermal stress formed during cooling as a result of a mismatch between the thermal expansion coefficients of the metal substrate and oxide scale.