电沉积方式对锆铌合金表面制备纯锆涂层结构与性能的影响  

Effect of Different Electrodeposition Methods on Structure and Properties of Pure Zirconium Coating on Zirconium-Niobium Alloy Substrate

作　　者：李雨莎 刘艳红 李怀林 李光彬 张迎春[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京 [2]国家电投集团科学技术研究院有限公司,北京

出　　处：《材料科学》2019年第11期1001-1010,共10页Material Sciences

基　　金：国家科技重大专项子课题(2015ZX06004001-002)。

摘　　要：金属锆可以有效降低失水事故下包壳的氧化速率,改善反应堆的安全裕量。本文采用FLINAK-K2ZrF6熔盐体系,分别以直流,单脉冲,正反脉冲的电沉积方式,在锆铌合金基体表面进行了纯锆涂层的制备。通过XRD、SEM以及划痕测试等技术,对比研究了不同电沉积方式下所得到纯锆涂层的晶体结构与显微组织、厚度以及与基体间的结合力。结果表明:采用直流、单脉冲和双脉冲电沉积方式均可以在锆铌合金基体上得到纯锆涂层,其结构都是密排六方结构。其中,直流电沉积得到的锆涂层表面孔隙率较大,锆晶粒沿(110)方向取向优先。脉冲电沉积得到的锆涂层更加致密,锆晶粒均沿(002)方向取向优先。其中双向脉冲电沉积得到的锆涂层硬度值最大,达到885 HV,与锆铌合金基体的结合强度最高,达到35 N。Zirconium can effectively reduce the oxidation rate of the cladding under water loss accidents and improve the safety margin of the reactor. In this work, zirconium coating on Zirconium-Niobium al-loy substrate was obtained by direct current, single pulse and double pulse electrodeposition methods from FLINAK-K2ZrF6 molten salt. The crystal structure, microstructure, thickness of the coatings and the adhesive strength between the coatings and Zirconium-Niobium alloy substrate were investigated by XRD, SEM and scratch test techniques. The results show that the pure zir-conium coating with hexagonal crystal structure can be obtained on the zirconium-niobium alloy substrate by both of direct current, single pulse and bidirectional pulse electrodeposition three methods. Zirconium coating obtained by direct current deposition has a large surface porosity, and the zirconium grains preferentially grow along the (110) direction. While the zirconium coating obtained by pulse electrodeposition is more compact, the zirconium grains preferentially grow along the (002) direction. The zirconium coating obtained by bidirectional pulse electrodeposition has the highest hardness value of 855 HV, and the bonding strength between zirconium coating and zirconium-niobium alloy substrate presents the highest value of 35 N.

关 键 词：电沉积 脉冲 锆涂层 

分 类 号：TG1[金属学及工艺—金属学]