摘要
目的在Zr合金包壳表面制备Cr涂层,以提高Zr合金包壳在事故环境下的抗高温氧化性能。方法采用多弧离子镀技术在Zr-4合金包壳上制备约17μm的Cr涂层,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、能量色散光谱(EDS)和电子探针(EPMA)等方法,分析试样氧化前后的相组成、微观形貌和扩散行为,并评估试样在1100、1200、1300℃空气环境中氧化后的高温氧化性能。结果沉积态Cr涂层显微结构致密均匀,(110)面有很强的织构。Cr涂层在高温空气中氧化60 min后,保持了涂层结构完整性。氧化后的Cr涂层Zr合金系统均为多层结构,包括外部Cr_(2)O_(3)层、中间Cr涂层、内部Cr-Zr扩散层和Zr合金基体。在涂层/基体界面上形成了具有Laves相的金属间ZrCr_(2)扩散层,ZrCr_(2)层下方的区域出现了大量分散的沉淀相。在Cr-Zr中间层和Zr合金界面处的不对称原子扩散导致Kirkendall空位生成,空位的聚集和合并导致空穴的形核和生长。结论Cr涂层表面形成了致密的Cr_(2)O_(3)层,提高了Zr-4合金的抗高温氧化性能。通过研究高温空气中Cr涂层Zr-4合金包壳材料的高温空气氧化/扩散行为,可为耐事故涂层的开发、制备和应用提供一定的理论指导和技术支持。
After the Fukushima nuclear power plant accident in 2011,accident tolerant fuel(ATF)materials become the focus of international research to cope with loss of the coolant accidents(LOCA)and more severe accidents in the nuclear industry.Zr alloys are widely used as fuel cladding structural materials because of their low thermal neutron cross section coefficient,good oxidation resistance,good mechanical properties and high corrosion resistance.Protective coatings are an effective way to increase the emergency response time in an accident.Cr coatings are one of the most promising ATF coatings because of their excellent oxidation resistance,high-temperature stability,and good deformation compatibility with Zr alloys in high-temperature environment.Cr coating was prepared on the surface of Zr alloy cladding by multi-arc ion plating technology to improve the high-temperature oxidation resistance of Zr alloy fuel cladding under accident environment.The high-temperature oxidation performance of the samples was evaluated at 1100,1200 and 1300℃in an air environment.The microstructure of as-deposited Cr coatings was dense and homogeneous,with a strong texture on the(110)planes.No microcracks or voids were found on the coating surface and cross section,and the Cr coating had a uniform thickness of about 17μm.The Cr coatings maintained the structural integrity after oxidation in air at 1100,1200 and 1300℃for 60 min.The oxidation products of all Cr coatings were identified as Cr_(2)O_(3).The relative strength of Cr(110)peak decreased with the increase of oxidation temperature.However,the relative strength of Cr_(2)O_(3)(110)peak increased.The oxidized Cr-coated Zr alloy system was multi-layer:external Cr_(2)O_(3)layer,intermediate Cr coating,internal Cr-Zr diffusion layer,and Zr alloy substrate.No microvoids,cracks or spalling were found on the surface of the dense Cr_(2)O_(3)layer,but mound oxide layer was formed on the specimen surface.Considering that the PBR of Cr_(2)O_(3)was 2.07,the strong volume expansion during hig
作者
李志平
宋鹏
张瑞谦
李青
LI Zhi-ping;SONG Peng;ZHANG Rui-qian;LI Qing(Key Laboratory of Reactor Fuel and Materials,Nuclear Power Institute of China,Chengdu 610213,China;Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2023年第9期241-246,264,共7页
Surface Technology
基金
云南省稀贵金属材料基因工程(202002AB080001)。
