In this study, we examined the interrelations among electroplating parameters, such as pulse current and electroplating duration; structural properties (such as crystalline structure, grain size, micro-cracking, and coating thickness); and physical properties (such as hardness and Fuel and Cladding Chemical Interaction (FCCI) barrier properties) of chromium barriers. Chromium coatings were electroplated onto HT9 steel disks using direct current and pulse current (PC) for different durations to investigate the influence of PC and coating thickness on the resulting microstructure and FCCI resistance. PC and a coating thicker than 20 μm were found to be effective for improving the barrier properties of Cr coatings. Scanning electron microscopy and electron backscatter diffraction analyses revealed sound microstructures without micro-cracking and twofold grain structures including large and small grains near the outer surface and HT9 substrate of the pulse-plated Cr coatings thicker than 20 μm, respectively. These resulted in reduced interdiffusion area and interdiffusion depth in the microstructure of the diffusion-coupled specimens. Heat-treatment of Cr coatings at 650 °C for times ranging from 50 to 1000 h revealed that the grain size increases with increasing heat-treatment time. The measured Vickers hardness of Cr coatings decreased with increasing grain size and resulted in only 42.6% hardness of as-electroplated Cr coatings after 1000 h of heat-treatment.

在这项研究中，我们研究了电镀参数之间的相互关系，例如脉冲电流和电镀持续时间。结构特性（例如晶体结构，晶粒尺寸，微裂纹和涂层厚度）；铬阻隔层的物理特性（例如硬度和燃料与覆层化学相互作用（FCCI）阻隔特性）。使用直流电和脉冲电流（PC）将铬涂层电镀到HT9钢盘上不同的时间，以研究PC和涂层厚度对所得显微组织和FCCI电阻的影响。发现PC和厚度大于20μm的涂层对于改善Cr涂层的阻隔性能有效。扫描电子显微镜和电子反向散射衍射分析揭示了无微裂纹的声音微观结构和双重晶粒结构，包括分别大于20μm的脉冲镀铬涂层的外表面和HT9基底附近的大晶粒和小晶粒。这导致扩散耦合样品的微观结构中的扩散面积和扩散深度减小。Cr涂层在650°C下热处理50到1000 h的时间表明，晶粒尺寸随热处理时间的增加而增加。Cr涂层测得的维氏硬度随晶粒尺寸的增加而降低，经过1000 h热处理后，电镀后的Cr涂层的硬度仅为42.6％。