针对超(超)临界电站锅炉高温受热面材料蒸汽侧氧化问题,该文开展国产镍基合金 C-HRA-1 在 620～650℃/25 MPa以及C-HRA-2 在 650℃/25 MPa超临界水环境的氧化实验研究.利用精密电子天平、扫描电子显微镜(scanning electron microscope,SEM)、X射线衍射(X-ray diffraction,XRD)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)以及原子力显微镜(atomic force microscope,AFM)等对材料氧化动力学、氧化膜微观形貌以及氧化膜物相组成进行分析.同时,开展 600℃/25 MPa超临界水环境氧同位素标记实验,探究镍基合金C-HRA-1在超临界水中的氧化机理.结果可知,C-HRA-1与C-HRA-2氧化后的主要物相为Cr2O3和NiCr2O4,NiO、CoO、MoO3以及NiFe2O4 也被检测到;合金中阳离子向外扩散导致了氧化膜的生长.国产镍基合金C-HRA-1在超临界水中表现出较高的抗氧化性能.
Study on Oxidation Behavior of Domestic Nickel Base Alloy C-HRA-1 and C-HRA-2 in Supercritical Water
In order to solve the problem of steam oxidation of high-temperature heating surface of ultra-supercritical power plant boiler,research on the oxidation of domestic nickel-base alloy C-HRA-1 at 620～650℃/25 MPa and C-HRA-2 at 650℃/25 MPa in supercritical water is carried out.The oxidation kinetics,microstructure and phase composition of the oxide film are analyzed by precision electron balance,scanning electron microscope(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and atomic force microscope(AFM).The oxygen isotope experiments at 600℃/25 MPa in supercritical water are also carried out to explore the oxidation mechanism of nickel base alloy C-HRA-1 in supercritical water.It is found that the main phase of C-HRA-1 and C-HRA-2 exposed to supercritical water is Cr2O3 and NiCr2O4,and the phase of NiO,CoO,MoO3 and NiFe2O4 are also detected.The outward diffusion of cations in the alloy leads to the growth of oxide film.The domestic nickel-base alloy C-HRA-1 has excellent oxidation resistance in supercritical water.
nicked-based alloyhigh temperature oxidationsupercritical wateroxidation mechanism
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