Transient Liquid Phase Bonding of Ultra High Temperature Ceramics

为了使超高温陶瓷得到更广泛的应用，必须开发一种适用于超高温陶瓷的有效连接策略。在本研究中，熔融Ni-Nb合金，将形成PTLP连接过程中使用Ni/Nb/Ni中间层HfB 2复合材料与MoSi 2添加处理的润湿行为进行了系统的研究。此外，还在1500°C下进行了具有Ni/Nb/Ni中间层的HfB 2复合材料的PTLP键合试验。所有Ni-Nb合金的接触角随时间迅速下降，并表现出良好的润湿HfB 2复合材料。其中，纯Ni液滴在加热过程中在1400°C左右完全消失。对润湿样品横截面的SEM-WDS显微结构分析显示，反应层包含涉及Si的多种金属间化合物，表明与烧结助剂MoSi 2的反应。当Nb含量为40at%时，Ni-Nb合金/HfB_2复合材料界面反应得到抑制。结果表明，采用Ni/Nb/Ni中间层连接HfB 2复合材料时，界面结合良好。

An effective joining strategy suitable for ultra high temperature ceramics will have to be developed for their wider application. In the present study, the wetting behavior of molten Ni-Nb alloys that will form during the PTLP bonding using Ni/Nb/Ni interlayer on a HfB2 composite processed with MoSi2 addition was systematically investigated. Additionally, a trial on PTLP bond of HfB2 composite with a Ni/Nb/Ni interlayer was also performed at 1500°C. The contact angles of all Ni-Nb alloys rapidly decreased with time and showed good wetting against HfB2 composite. Among them, the pure Ni droplet totally disappeared around 1400°C during heating. SEM-WDS microstructural analysis on the cross section of the wetting sample revealed that the reaction layer contained multiple intermetallic compounds involving Si, suggesting the reaction with the sintering aid MoSi2. With the 40at% Nb addition, the interfacial reaction at the Ni-Nb alloy/HfB2 composite interface was suppressed. Consequently, it was revealed that a well-bonding interface was achieved when HfB2 composite was bonded using the Ni/Nb/Ni interlayer.