ZrCr梯度界面层对Zr/Al_(2)O_(3)涂层体系抗热震性能影响及机理研究  

Effect of ZrCr Gradient Interfacial Layer on Thermal Shock Resistance of Zr/Al_(2)O_(3) Coating System and Its Mechanism

作　　者：杨红志 刘波[1] Yang Hongzhi;Liu Bo(Key Laboratory of Radiation Physics and Technology of Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China)

机构地区：[1]四川大学原子核科学技术研究所教育部辐射物理及技术重点实验室,四川成都610064

出　　处：《稀有金属材料与工程》2022年第5期1773-1779,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(11605116)。

摘　　要：采用中频磁控溅射和超音速等离子喷涂依次在锆合金(Zr-4)基体表面制备了Zr(84.61at%)Cr/Zr(17.39at%)-Cr/Al_(2)O_(3)(ZrCr梯度界面层)和Al_(2)O_(3)(无ZrCr梯度界面层)涂层。利用XRD、SEM和HRTEM等重点分析了ZrCr梯度界面层对Zr-4/Al_(2)O_(3)涂层界面微观结构、结合强度和抗热震性能的影响。结果表明:通过增设ZrCr梯度界面层,能显著提升Zr-4/ZrCr/Al_(2)O_(3)体系结合强度至50.3±2.52 MPa,较Zr-4/Al_(2)O_(3)体系结合强度值提升约46%;循环热震条件下,Zr-4/ZrCr/Al_(2)O_(3)体系膜基界面完整,与ZrCr梯度界面层能显著提升界面结合强度,喷涂及热震实验过程中ZrCr梯度界面层Cr原子优先形成较致密的Cr_(2)O_(3)能进一步有效抑制氧扩散至Zr-4有关;Zr-4/Al_(2)O_(3)膜基界面则出现明显开裂甚至剥离行为,其主因是Zr-4/Al_(2)O_(3)两者界面热应力集中而导致Zr-4/Al_(2)O_(3)界面开裂;HRTEM和EDS线扫描结果证实在Zr-4/Al_(2)O_(3)界面开裂处形成的疏松ZrO_(2)氧化物是后续热震循环中进一步加剧涂层大面积剥落失效的根本原因。Two coatings(Zr(84.61at%)Cr/Zr(17.39at%)Cr/Al_(2)O_(3) and Al_(2)O_(3) without ZrCr gradient interfacial layer)were fabricated on zirconium alloy(Zr-4)substrate by intermediate frequency magnetron sputtering and supersonic plasma spraying.The influence of ZrCr gradient interfacial layer on the interface microstructure,adhesive strength and thermal shock resistance of the two coatings was studied by XRD,SEM and HRTEM.The results show that the adhesive strength of Zr-4/ZrCr/Al_(2)O_(3) system can be significantly increased to 50.3±2.52 MPa,by adding ZrCr gradient interfacial layer about 46%higher than that of Zr-4/Al_(2)O_(3) system.In the process of thermal shock test,it is found that the interface of Zr-4/ZrCr/Al_(2)O_(3) system remains intact because of its higher adhesive strength and formation of dense Cr_(2)O_(3) in ZrCr gradient transition layer protecting Zr-4 substrate from oxidation.The interface of Zr-4/Al_(2)O_(3) system,however,exhibits obvious cracking or even peeling behavior,and the main reason is thermal stress concentration in the interface of Zr-4/Al_(2)O_(3) system.HRTEM and line scanning results confirmed that in the process of subsequent thermal shock test,the formation of loose ZrO_(2) at the Zr-4/Al_(2)O_(3) interface cracking position is the root cause for aggravating the large-scale peeling to failure of the coating.

关 键 词：ZrCr梯度界面层 超音速等离子喷涂 微结构 结合强度 抗热震性能 

分 类 号：TG154.5[金属学及工艺—热处理]