耐事故燃料用碳化硅包壳材料的热扩散连接技术

Thermal Diffusion Bonding Technology of SiC Cladding Materials for Accident Tolerant Fuels

碳化硅及其复合材料是最可能用于核电耐事故燃料的包壳材料。从核燃料元件包壳材料的需求出发,利用钛箔作为连接介质,采用热扩散连接技术对碳化硅的密封连接进行了研究。实验结果表明,扩散温度为1500℃,压力为10 MPa,连接时间1h,能够获得稳定的碳化硅连接样品。连接样品的平均剪切强度为88.63 MPa。显微分析表明C和Si元素在Ti箔中发生扩散,并与Ti发生反应形成稳定的连接界面,连接层边缘主要为Ti3SiC2相,连接层中心由Ti和TiC组成。

Silicon carbide and its composites are the cladding materials most likely used for nuclear accident tolerant fuels. In consideration of the requirement of cladding materials for nuclear fuel elements, titanium foil was used as connecting medium, the thermal diffusion bonding technology was used for studying the sealing bonding of silicon carbide. The experimental results show that a stable silicon carbide bonding sample can be obtained under diffusion temperature of 1500 C,pressure of 10 MPa and bonding time of 1 h.The average shear strength of bonded samples is 88.63 MPa. Microscopic analysis shows that C and Si elements diffuse in Ti foil and react with Ti to form a stable bonding interface. The edge of the bonding layer is mainly Ti3SiC2 phase, and the center of the bonding layer is composed of Ti and TiC.