超临界水中新型奥氏体耐热钢HR80耐腐蚀性能研究

Study on Corrosion Behavior of New Austenitic Heat-resistant Steel HR80 in Supercritical Water

使用反应釜开展新型奥氏体耐热钢HR80在650℃、25 MPa超临界水环境氧化腐蚀试验,获得HR80钢在超临界水中的抗腐蚀性能.利用电子天平对实验前后的试样进行称重测量,利用扫描电镜(SEM)、X射线衍射仪(XRD)、X射线能谱仪(EDS)对HR80钢的氧化膜表面形貌、横截面形貌、物相以及氧化膜中元素成分分布进行表征.根据腐蚀增重曲线可知,HR80钢的腐蚀动力学遵循抛物线腐蚀规律.氧化膜为典型的双层结构,外层主要为Fe_(3)O_(4)和Fe_(2)O_(3),内层主要由Fe-Cr尖晶石组成.此外,氧化层与基体之间形成了Cr_(2)0_(3)氧化膜.提出了HR80钢在超临界水中的氧化过程以及氧化膜形成的主要原因.

Corrosion tests of new austenitic heat-resistant steel HR80 in supercritical water environment at 650℃ and 25 MPa were carried out to obtain the corrosion resistance of HR80 steel in supercritical water dioxide.The experiments were performed in the autoclave.The samples were weighed before and after the exposure by using an electronic balance.By means of scanning electron microscope(SEM),X-ray diffractometer(XRD)and energy dispersive X-ray spectroscopy(EDS),the oxidation film surface morphology,cross-sectional morphology,physical phase and element composition distribution in oxide film were characterized.According to the corrosion weight gain curve,the corrosion kinetics of HR80 steel followed parabolic corrosion law.The oxide film was a typical doublelayer structure,the outer layer was mainly Fe304 and Fe_(2)O_(3),inner layer was mainly composed of Fe-Cr spinel.Besides,a continuous Cr_(2)0_(3) oxide film was formed between the oxide layer and the matrix during the 650℃ oxidation test.The oxidation process of HR80 steel in supercritical water and the main reasons for the formation of oxide film were proposed.