用Ni＋Ti粉坯热压反应烧结连接SiC

Hot pressing reaction sintering joining of SiC with Ni ＋ Ti fillers

用Ni＋Ti粉坯作为焊料，采用热压反应烧结连接法连接SiC陶瓷，研究了焊接温度、保温时间、连接压力和压坯厚度对试样连接强度的影响规律。在本文所述试验范围内，确定的最佳工艺为：连接温度1100℃，保温时间20min，焊接压力12．7MPa，焊料压坯厚度0．3mm，所得连接件的相对抗弯强度为53％。微观结构和XRD物相分析表明：在Ni＋Ti粉坯与sic陶瓷接合界面处，发生了元素的互扩散和界面反应，在适当的工艺条件下，接头界面具有在NiTi、Ni3C、Ni16Ti6Si7混合物的基体中弥散分布TiC相的微观组织，借助于主要基体相NiTi的韧性和与母材SiC晶格匹配良好的TiC可以实现有效的界面结合。

Joining recrystallized SiC ceramics has been realized by a hot pressing reaction sintering joining with the particulate filler composed of Ni ＋ Ti powders. The joining experiments were conducted by employing a Gleeble 1500 thermo-mechanical testing machine. The effects of the technological parameters such as joining temperature, holding time, joining pressure and thickness of filler compact on bending strength of joints have been investigated. The relative bending strength of the joint is 53 % under the technological parameters of 1100℃ for 20minutes, welding pressure of 12.7MPa, filler compact thickness of 0.3mm. Microstructures of interracial reaction have been examined by SEM, EDS and XRD. Microstructure analysis indicates that interdiffusions and interfical reactions take place at the interfaces during welding. Under proper technological condition the joint interface has the microstructure of TiC dispersed in the mixture of NiTi, Ni3C and Ni16Ti6Si7. Owing to the tenacity of NiTi and the good match of crystal lattice of TiC and SiC. a successful bonding is achieved.