Ti3SiC2在高流速液态PbBi介质中的冲刷腐蚀机制研究

Accelerator Driven subcritical System (ADS) has been extensively investigated as an innovative nuclear reactor to dissolve the nuclear fuel waste. Heavy Liquid Metal(HLM, Lead alloy cooled reactor is considered as one of the most promising reactors of generation Ⅳ for nuclear electric system. Pb\PbBi has many advantages due to their high boiling temperatures, relative inertness and neutronics, but the corrosion behavior of reactor material with Pb\PbBi is one of the key questions that should be resolved first. The component of reactor especially for the impeller and bear of main pump, the relative velocity between the liquid metal and the structural surface will be kept at about 10 m/s or even higher at some local areas. Material capable to operate in fluent liquid metal shall be individuated and qualified. Thus, the corrosion-erosion investigation and assessment behavior of structural materials suitable for reactor became one of the main challenges and hot research field in developing ADS. Among the studies, Ti3SiC2 has attracted the attention of researchers for its special properties and will be a candidate material for ADS. Thus Erosion-corrosion mechanism investigation of Ti3SiC2 in Lead Bismuth Eutectic(LBE) with high volocity will be performed in this study, which could provide technical support for the material selection of future reactor main pump, further applicaiton of cermat and guideline for the further study of structural materials corrosion for new generation reactor of China.

加速器次临界嬗变系统（Accelerator Driven subcritical System）通过中子与高放核废料发生嬗变反应来处理核废料，有望解决高放核废料污染问题，其中铅基冷却反应堆因具有良好的中子学和传热特性被国际原子能机构选作第Ⅳ代核电反应堆候选方案。采用铅基合金作为冷却剂具有诸多优势，但与结构材料的相容性是铅基反应堆发展过程中需要解决的关键难题，相对堆内其他构件核主泵的叶轮和轴承表面流速更高（可以达到10m/s），受到冲刷腐蚀作用强。因此，选择耐高温、耐腐蚀、尤其耐铅基合金高流速场冲刷腐蚀的材料作为反应堆结构材料成为研究热点。Ti3SiC2材料因具有耐高温、耐腐蚀、机械加工性能优良等特点成为候选结构材料。本项目率先开展Ti3SiC2与高速PbBi介质相容性和腐蚀机理研究，将为我国自主研制铅基反应堆提供技术支持和理论依据，拓展金属陶瓷材料的应用领域。

铅基冷却反应堆因具有良好的中子学和传热特性被国际原子能机构选作第IV代先进核能系统候选方案。但堆内结构材料与铅基合金的相容性是铅基反应堆发展过程中需要解决的关键难题。相对其他构件，核主泵的叶轮和轴承表面流速更高（可以达到10m/s），受到冲刷腐蚀作用强。Ti3SiC2材料因具有耐高温、耐腐蚀、机械加工性能优良等特点成为核主泵候选结构材料。本项目以Al2O3弥散增强的Ti3SiC2为研究对象，依托自主研制的液态PbBi高速旋转腐蚀平台，研究了PbBi流速和温度对Ti3SiC2在液态PbBi中腐蚀行为的影响。主要结果如下：（1）成功研制了Al2O3弥散增强Ti3SiC2材料；（2）设计并建造了液态PbBi高速旋转腐蚀平台，装置最高流速最高可达21.8m/s，满足腐蚀实验需求；（3）随着PbBi流速的增加，Ti3SiC2腐蚀程度逐渐加剧，Ti3SiC2在高流速液态PbBi中的腐蚀机制主要为溶解冲刷腐蚀；（4）1000℃条件下Ti3SiC2在液态PbBi中出现了明显的腐蚀现象，为非均匀的溶解腐蚀。本项目研究成果可为我国铅基反应堆的选材提供技术支持和理论依据。