中文摘要：

为探究不同Cr含量的镍基合金在熔盐环境中的腐蚀行为，在700℃的FLiNaK（LiF—NaF-KF：46．5—11．5-42mol％）盐中对HastelloyB-2、Haynes242、HastelloyS、GH3030和Hastelloyx五种不同Cr含量的镍基高温合金进行了400h的腐蚀实验。利用扫描电子显微镜（ScanningElectronMicroscope，SEM）和电子探针（ElectronProbeMicroanalysis．EPMA）对腐蚀后样品进行表征，结合样品失重，对不同Cr含量合金的腐蚀规律进行归纳分析。结果表明，合金的耐腐蚀性能受其Cr含量的影响较大，低Cr合金（HastelloyB．2和Haynes242）具有较好的耐熔盐腐蚀性能，高Cr合金耐熔盐腐蚀性能较差，当合金中Cr含量大于20％时（GH3030和HastelloyX），腐蚀急剧增加，合金表面出现明显的贫Cr层，合金不适合在熔盐环境中应用。

英文摘要：

Background： Corrosion of the structural materials of Molten Salt Reactor （MSR） has been recognized as a challenge that prevents the MSR from long term operation. Oak Ridge National Laboratory （ORNL） has revealed that corrosion occurs predominantly through dealloying of Cr from the candidate nickel-based high temperature alloys Therefore, a systematic study on the corrosion characteristics of candidate structural materials is needed to ensure their applications in MSR. Purpose： The present work is to evaluate the corrosion behaviors of some nickel-based alloys with different Cr content as well as to supply more corrosion data of materials in molten fluoride salts for reliable selection of structural materials. Methods： Static corrosion tests of five kinds of nickel-based high temperature alloys （Hastelloy B-2, Haynes 242, Hastelloy S, GH 3030 and Hastelloy X） were performed in purified molten FLiNaK salt at 700 ℃ for 400 h. The microstructural morphology and chemical composition of the samples were examined by Scanning Electron Microscope （SEM） and Electron Probe Microanalysis （EPMA）. Results： Hastelloy B-2 and Haynes 242 with low Cr content exhibited better corrosion resistance, while the high Cr-content alloys, GH 3030 and Hastelloy X, exhibited severe corrosion after the corrosion tests. Conclusion： It was found that the corrosion was correlated with the original Cr-content of the alloys, and the weight-loss/area due to corrosion increased with the Cr-content of alloys. When the Cr content of alloys is higher than 20 wt.%, these alloys would suffer severe corrosion in molten fluoride salt environments.