UO_(2)/SiC全陶瓷微密封燃料制备及其高温导热性能  

Preparation and high temperature thermal conductivity of UO_(2)/SiC fully ceramic microencapsulated pellets

作　　者：段丽美[1] 王志毅 黄奇奇 谢良 胡凤云[1] 钟毅 杨振亮 李冰清 许靖堃 王明珊 高瑞[1] 褚明福[1] DUAN Limei;WANG Zhiyi;HUANG Qiqi;XIE Liang;HU Fengyun;ZHONG Yi;YANG Zhenliang;LI Bingqing;XU Jingkun;WANG Mingshan;GAO Rui;CHU Mingfu(Institute of Materials,Chinese Academy of Engineering Physics,Mianyang 621900,China;School of New Energy and Materials,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]中国工程物理研究院材料研究所 [2]西南石油大学新能源与材料学院

出　　处：《粉末冶金技术》2025年第2期135-143,共9页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(51604250,U20B2021,U22B20129,52174348,52072322);核能开发项目(HNKF202001);中物院基金资助项目(JMJJ202101)。

摘　　要：利用自研磨球化包覆和放电等离子烧结技术,通过调控升温速率、温度、压力、SiC添加量等参数,制备了一系列UO_(2)/SiC复合全陶瓷微密封燃料芯块。在金相显微镜和扫描电子显微镜下观察了芯块的物相组成与结构特征,并通过激光热导仪获得了芯块从室温到1200℃的热导率数据,讨论了不同工艺参数对芯块组织及热导率的影响。结果表明,UO_(2)@SiC复合包覆颗粒具有良好的球形度和包覆效果,UO_(2)/SiC复合芯块中SiC基体呈现三维连通的网状结构特征。烧结压力对芯块中UO_(2)颗粒的结构完整性影响较大,烧结温度对SiC基体的形貌、相对密度等影响较大。相对密度低于95%时,烧结温度对热导率的影响更大;相对密度高于95%时,SiC添加比例对热导率影响更大。所制备燃料芯块的热导率相比纯UO_(2)提升最高达到256.6%。A series of UO_(2)/SiC composite fully ceramic microencapsulated(FCM)pellets were prepared by self-grinding spheroidization coating and spark plasma sintering.The parameters,such as heating rate,sintering temperature,sintering pressure,and SiC content,were regulated.The phase composition and structural characteristics of the pellets were observed by metallographic microscopy and scanning electron microscopy.The thermal conductivity(TC)of the pellets from room temperature to 1200℃ was obtained by laser thermal conductivity meter.The effects of process parameters on the microstructure and TC of the pellets were discussed.The results indicate that,the UO_(2)@SiC composite particles are nearly spherical and well coated.The SiC matrix in UO_(2)/SiC composite pellets exhibits a three-dimensional interconnected network structure.The sintering pressure has a significant influence on the structural integrity of UO2 particles in the pellets.The sintering temperature has a significant influence on the morphology and relative density of the SiC matrix.When the relative density is lower than 95%,the sintering temperature has a greater effect on the TC of the fuel pellets;when the relative density is higher than 95%,the SiC content has a greater impact on the TC.The TC of the FCM pellets prepared in this study is increased by up to 256.6% compared with the pure UO2.

关 键 词：事故容错燃料 全陶瓷微密封 芯块 热导率 

分 类 号：TB3[一般工业技术—材料科学与工程] TF125[冶金工程—粉末冶金]