Joining dense Si3N4 to porous Si3N4 using a novel glass

In this work, we developed a new β-LiAlSi2O6/Mg2SiO4 glass-ceramic interlayer to join dense Si3N4 and porous Si3N4 ceramics for high-temperature applications. The microstructure and phases of the joint were investigated using systematic analysis methods and the mechanism for the interfacial bonding was proposed. The double crystalline phases of β-LiAlSi2O6 and Mg2SiO4 precipitated in the joint seam during the joining process, forming a novel glass-ceramic interlayer with high crystallinity. Due to the good wettability of liquid glass on porous Si3N4, a gradient and dense infiltration layer was formed in porous Si3N4 and reinforced it, which improved the mechanical strength of the whole joint. In this case, the shear strength of the joint reached 78 MPa, and it could still maintain 74 MPa up to 850 °C, which fully demonstrated the high-temperature resistance of the joint.

中文翻译：

在这项工作中，我们开发了一种新的 β-LiAlSi 2 O 6 /Mg 2 SiO 4微晶玻璃中间层，用于连接致密 ​​Si 3 N 4和多孔 Si 3 N 4陶瓷，用于高温应用。使用系统分析方法研究了接头的微观结构和相，并提出了界面结合的机制。β-LiAlSi 2 O 6和Mg 2 SiO 4双晶相在接合过程中在接缝处析出，形成一种新型的高结晶度微晶玻璃中间层。由于玻璃液在多孔Si上的润湿性良好3 Ñ 4，形成在多孔硅的梯度和致密浸润层3 Ñ 4和增强它，这提高了整个接头的机械强度。在这种情况下，接头的剪切强度达到了 78 MPa，在 850 ℃下仍能保持 74 MPa，充分展示了接头的耐高温性能。