摘要
在核反应堆堆芯核燃料包壳中,用锆(Zr)合金表面包覆Cr涂层被认为是短期内最有可能投入商业应用的技术。熔盐电沉积技术有望解决包壳Zr合金表面高质量Cr涂层的高效低成本制备难题。本研究采用水溶液电沉积和熔盐电沉积方法依次在Zr合金基体表面制备Ni过渡层和Cr涂层,对制备得到的Zr/Ni/Cr试样进行组织结构表征、结合力和纳米硬度测试及高温氧化行为研究。结果表明,Zr合金表面的Ni/Cr涂层均匀致密,与基体间的结合力约为151 N。Zr/Ni/Cr从内到外各层的硬度和弹性模量均逐渐升高,呈准梯度过渡。其中Cr涂层的表面粗糙度约为2μm,硬度和弹性模量分别为2.86 GPa和172.86 GPa。Zr/Ni/Cr试样在1000和1200℃高温蒸汽氧化过程中分别表现出近抛物线和近线性规律,表明Ni/Cr涂层能够在1000℃下对Zr合金基体起到良好的保护效果。Zr合金表面Ni/Cr涂层的高温氧化失效机制与Ni过渡层的快速扩散、Cr层的氧化和扩散消耗以及Zr沿Cr晶界快速扩散导致的Cr层性能弱化密切相关。
Cr coatings on zirconium(Zr)alloy surface for nuclear fuel cladding in nuclear reactor cores is considered to be the most likely technique for commercial application in a short term.The molten salt electrodeposition technique is expected to solve the problem of efficient and low cost preparation of high quality Cr coatings on the surface of Zr alloy claddings.This research adopted aqueous solution electrodeposition and molten salt electrodeposition methods to prepare Ni transition layer and Cr coating on the surface of Zr alloy substrate sequentially,and carried out the characterization of the microstructure,the bonding force and nano-hardness test as well as the study of the high-temperature oxidation behavior of the Zr/Ni/Cr specimens obtained from the preparation.The results show that the Ni/Cr coating on the surface of Zr alloy is uniform and dense,and the bonding force between the coating and the substrate is about 151 N.The hardness and elastic modulus of Zr/Ni/Cr increase gradually from the inner layer to the outer one with a quasi-gradient transition.The surface roughness of the Cr coating is about 2μm,and the hardness and elastic modulus are 2.86 GPa and 172.86 GPa,respectively.The Zr/Ni/Cr specimen shows nearly parabolic and nearly linear patterns during steam oxidation at high temperatures of 1000 and 1200℃,respectively,indicating that the Ni/Cr coating is able to provide good protection to the Zr alloy matrix at 1000℃.The high-temperature oxidation failure mechanism of Ni/Cr coating on Zr alloy surface is closely related to the rapid diffusion of the Ni transition layer,the oxidation and diffusion depletion of the Cr layer,and the weakening of the Cr layer due to the rapid diffusion of Zr along the Cr grain boundaries.
作者
朱利安
袁伟超
王淑祥
王震
叶益聪
白书欣
Zhu Li’an;Yuan Weichao;Wang Shuxiang;Wang Zhen;Ye Yicong;Bai Shuxin(College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2024年第10期2805-2822,共18页
Rare Metal Materials and Engineering
基金
湖南省青年人才支持计划(2020RC3034)。
关键词
耐事故燃料包壳
Cr涂层
ZR合金
电沉积
氧化
accident tolerant fuel cladding technology
Cr coating
Zr alloy
electrodeposition
oxidation