钨涂层的电沉积机理及晶面取向调控机制的研究

Tungsten is a promising candidate material as a plasma facing material (PFM) in ITER due to its highest melting point, low sputtering yield, and good thermal properties. Research has shown that the preferential crystal orientation influenced greatly the irradiation behavior of tungsten. Therefore, the research on grain growth of tungsten coating with adjusting the crystal orientation is very significant for the development of fusion reactor. Most of researches on electrodepostion of tungsten have been focused on the molten salt systems and technological parameters, while lacking control on preferential crystallographic orientation of tungsten coating. This research has prepared PFMs (tungsten) by electrodepositing tungsten coatings on cooper alloy (CuCrZr), which has been selected as a heat sink material. The electrochemical reduction process of tungsten in molten salt was investigated by modern electrochemical methods, such as cyclic voltammetry, chronopotentiometry, chronoamperometry. X-Ray Diffractio(XRD), scanning electon microscope(SEM), transmission electron microscopy(TEM) were used to study the influence of electroplating parameters on the crystal structure and physical properties. The regulation mechanism and approach of microstructure and preferential crystal orientation were investigated by the relationship between the material design, microstructure and preferential crystal orientation, which could provide theoretical basis for the preparation of tungsten coating with adjusting the crystal orientation.investigated by the relationship between the material design, microstructure and preferential crystal orientation, which could provide theoretical basis for the preparation of tungsten coating with adjusting the crystal orientation.

金属钨涂层作为未来托卡马克/聚变堆中最可能全面使用的面向等离子体材料(PFM， Plasma Facing Material)，其抗辐照性能同晶面取向有密切的联系。因此，开展对钨涂层晶粒生长以及晶面择优取向调控的研究，对于聚变堆的发展具有重要的战略意义。现阶段，电沉积钨涂层的研究主要集中于体系的选择、工艺参数的选定等方面，钨涂层晶面择优取向的调控机制尚缺乏系统深入的分析。本项目以含氧酸盐熔盐体系中钨涂层的电沉积制备为研究对象，通过循环伏安、稳态极化以及恒电流、电位阶跃等电化学方法研究钨的电还原和电结晶机理；探讨工艺参数对钨涂层微观组织结构和晶面择优取向的影响，将钨涂层材料的微观组织结构、晶面择优取向同电沉积机理统一分析，建立“材料设计－组织结构－晶面取向”的关联性，揭示材料设计对钨涂层组织结构和择优取向的调控机制和途径，为钨涂层的熔盐电沉积制备以及晶面择优取向的调控提供理论支撑。

金属钨涂层作为未来托卡马克聚变堆中最可能全面使用的面向等离子体材料（PFM，Plasma Facing Material），其抗辐照性能同晶面取向有密切的联系。本项目充分利用电沉积技术的优势，选择合适的钨涂层电沉积体系，探讨该体系下钨涂层电沉积机理，并系统研究了电沉积工艺参数和热处理工艺对涂层晶面择优取向的影响。研究发现，Na2WO4-WO3二元体系中，阳极金属钨作为离子源能够不断地补充钨酸根离子，保证了体系的稳定性。在上述体系中，电流密度和电流波形对钨涂层晶面择优取向有明显的影响，但电沉积时间的变化对晶面择优取向没有明显的影响；通过改变电沉积参数可以实现对钨涂层（110）面、（200）以及（211）面择优取向进行选择调控。研究还发现，热处理工艺对晶面择优取向的影响与热处理温度有密切的关系；高温热处理下，钨涂层晶面择优取向可以由（200）面转变为（110）面；中低温热处理过程没有明显地改变钨涂层的晶面择优取向。此外，本项目还开展了单连接线电沉积钨涂层和低共熔离子液体电沉积金属涂层等研究工作，为金属涂层的电沉积制备提供了更多的思路和参考。.