为分析第三代太阳能热发电技术熔盐与低温罐选材的相容性,该文以一种低熔点（142 ℃）、高分解温度（>700 ℃）的混合熔盐为腐蚀环境,通过静态腐蚀实验研究碳钢（A515Gr70）和两种低合金钢（Q345R、15CrMoR）在450 ℃混合熔盐中的腐蚀行为。采用失重法测量不同金属的腐蚀速率。通过扫描电子显微镜（SEM）、X射线衍射（XRD）和能谱仪（EDS）对金属腐蚀表面的微观形貌、相组成和微区成分进行分析。结果表明：碳钢不含有耐腐蚀元素Cr、Ni和Mo,腐蚀速率最大。15CrMoR表面氧化层以疏松多孔的Fe2O3为主,不能阻止熔盐浸入金属基体内部,导致氧化程度加重,耐腐蚀性较差。Q345R表面氧化层由致密性好的FeCr2O4、NiO和TiO2组成,对金属基体具有保护性,耐腐蚀性最佳。
Abstract
In order to analyze the compatibility between the molten salt of the third generation solar thermal power generation technology and the materials of cryogenic tank,this article takes a mixed molten salt with low melting point （142 ℃） and high decomposition temperature （>700 ℃） as the corrosion environment,and studies the corrosion behavior of carbon steel （A515Gr70） and two low alloy steels （Q345R,15CrMoR） in the mixed molten salt at 450 ℃ through static corrosion experiments. The weight-loss method is adopted to measure the corrosion rates of different metals. The microstructure, phase composition and micro-area composition of the metal corrosion surface are analyzed by SEM, XRD and EDS. The results show that carbon steel does not contain corrosion resistant elements Cr, Ni and Mo,and the corrosion rate is the highest.The oxide layer on the surface of 15CrMoR is mainly composed of porous Fe2O3,which cannot prevent molten salt from immersing into the metal matrix,resulting in increased oxidation and poor corrosion resistance.The oxide layer on the surface of Q345R is composed of FeCr2O4, NiO and TiO2 with good compactness, which has a protective effect on the metal matrix and has the best corrosion resistance.
关键词
太阳能热发电 /
腐蚀 /
腐蚀速率 /
合金钢 /
熔盐 /
氧化层
Key words
solar thermal power generation /
corrosion /
corrosion rate /
alloy steel /
molten salt /
oxide layer
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基金
国家自然科学基金（52076006）; 国家重点研发计划（2022YFB4202402）
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