摘要
锆合金是重要的核燃料包壳材料,在包壳表面沉积抗高温水蒸气氧化涂层是在失水事故中避免核泄漏的有效途径,然而涂层在高温氧化过程中存在氧化产物不稳定及界面扩散问题。用磁控溅射的方法在Zr-4合金表面沉积Mo/Al/Cr复合涂层,拟利用Al层生成氧化铝提升抗氧化温度上限,利用Mo层阻挡Al与Zr-4基体的扩散。用SEM表征涂层的表面及横截面形貌,利用XRD分析涂层物相结构,用纳米压痕的方法评价涂层的力学性能,用管式炉连接水蒸气发生器来评价涂层的抗高温水蒸气氧化性能。结果表明:在锆合金表面制备的Mo/Al/Cr复合涂层与基体结合良好,结构完整,界面清晰,硬度高于Zr-4合金基体。在高温水蒸气氧化试验中,复合涂层中的Al会发生熔融,导致涂层结构的破坏而不能生成连续致密氧化铝膜。在Cr层、Al层失效的情况下,Mo层可以有效阻挡Al及O元素向基体内部扩散。探讨了Al作为抗氧化层及Mo作为扩散阻挡层的可行性,试验结果可为核燃料包壳涂层的设计选材提供借鉴和支撑。
Zirconium alloys are important materials for nuclear fuel claddings.When a loss of coolant accident (LOCA) occurs,the zirconium alloy cladding will be oxidized by the high-temperature (1 000℃) steam,generating hydrogen and releasing significant heat.If the emergency action is not taken promptly,a hydrogen explosion or nuclear leakage will occur.The deposition of coatings with high temperature steam oxidation resistance,such as M_(n+1)AX_(n) phase,Fe Cr Al,and Cr coatings,on the cladding surfaces is an effective mechanism for delaying the hydrogen explosion and nuclear leakage of a LOCA.Of all the coatings,the Cr coating is considered the most promising for practical application because of its good oxidation resistance in high-temperature steam and excellent corrosion resistance in subcritical water.However,the oxidation products of Cr coatings are unstable,and the Cr-Zr eutectic reaction will occur at the interface during the process of high-temperature oxidation,which limits the performance of the Cr coatings.In this paper,a Mo/Al/Cr composite coating is deposited on the surface of a Zr-4 alloy by the magnetron sputtering method.The outer Cr layer is designed to resist the corrosion of the subcritical water under normal conditions.The Al layer is proposed to improve the upper limit of the oxidation resistance of the composite coating during accident conditions because aluminum oxide is more stable than chromium oxide at high temperatures.The Mo layer is designed to inhibit the diffusion between the Al layer and the Zr-4substrate.Cr coatings and Al/Cr coatings are also prepared on the surfaces of the Zr-4 alloys as reference samples.The surface and cross-sectional morphologies of the coatings are characterized by scanning electron microscopy;the phase structures of the coatings are analyzed by X-ray diffraction;the mechanical properties of the coatings are evaluated by the method of nano-indentation;and the high temperature steam oxidation resistance of the coatings is evaluated using a tube furnace connected t
作者
张腾飞
廖海燕
阮海波
苏永要
王锦标
徐照英
董井忍
ZHANG Tengfei;LIAO Haiyan;RUAN Haibo;SU Yongyao;WANG Jinbiao;XU Zhaoying;DONG Jingren(College of Materials Science and Engineering,Chongqing University of Arts and Sciences,Chongqing 402160,China;College of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;College of Materials Science and Engineering,Chongqing University,Chongqing 401331,China)
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2023年第2期97-103,共7页
China Surface Engineering
基金
国家自然科学基金(U20A20232)
重庆市教委科研(KJQN202101316,KJQN201901340,KJQN202101303)
重庆市科技局(cstc2021ycjhbgzxm0176,cstc2018jcyj-yszx X0003)资助项目。
