熔融氟化物腐蚀电化学机制与耐蚀陶瓷扩散障研究

熔融氟化物广泛应用于熔融盐核反应堆、电解铝等工业领域。近年来，作为第四代反应堆，熔融盐电堆再次成为热门研究课题。我国于2011年正式启动了钍基熔盐堆核能系统。熔融氟化物的强腐蚀性使得结构材料的腐蚀成为熔盐电堆发展不可回避的问题。基于我国熔盐电堆发展需求，本项目将首先研究建立熔融氟化物腐蚀电化学研究理论与技术，通过设计不同金属电偶对、单/多晶镍基合金、单/双相合金及控制不同温度场等，研究揭示金属材料在熔融氟化物中的腐蚀电化学机制，描述腐蚀动力学过程；利用金属Ni的优异抗熔融氟化物腐蚀性能，应用熔盐电沉积技术在Ni涂层与基体合金间制备金属陶瓷(硼或氮化物)扩散障，研究Cr等在陶瓷层中的扩散动力学及陶瓷层/Ni涂层的抗熔融氟化物腐蚀性能与机制。本项研究对于揭示熔融氟化物腐蚀电化学机制，完善熔融氟化物腐蚀电化学研究理论与技术，发展抗腐蚀材料/涂层及推动我国熔盐电堆技术的发展具有积极意义。

Molten fluorides have been widely used in molten Salt Reactors(MSR) and aluminimum electrolysis industry. In recent years, MSR as the fourth-generation nuclear reactor is becoming a hot research topic again. In 2011, Thorium Molten Salt Reactors were launched by our country. However, the extremelly strong corrosiveness of molten fluorides has made the corrosion of structure materials become an unaoidable problem for the devemopment of MSR. In consideration of the devemplment of MSR in our conutry, it will be attempted firstly to establish electrochemical theroy and techniques for the study of corrosion in molten fluorides in this project. Then, electrochemical corrosion mechanism and corrosion kinetcis of metallic materials in molten fluorides will be investigated by designing different couples, single crystal/polycrystalline Ni-based alloys, single-phase/two-phase alloys and by designing molten salts with different temperature gradients. Taking into account the excellent corrosion resistance of pure Ni in molten fluorides, it was proposed to electrodeposit a diffusion barrier of metallic ceramics from molten salts between the substrate alloy and Ni coating to inhibit the outward diffusion of alloying elements from the substrate. The diffusion kinetcis of Cr in the ceramic barriers and the corrosion behavior of the composite ceramics/Ni coatings in molten fluorides will also be studied. This project is expected to be helpful to understanding the corrosion mechanism of materials in molten fluorides, to improving electrochemical theory and techniques for the study of corrosion in molten fluorides, to developing the corrosion resistant materials/coatings and to the development of MSR in our country.