Adjusting the microstructure of joints in laser-joined silicon carbide (SiC) devices for enhanced high temperature resistance

激光支持的焊接可以有效地制造连接的碳化硅基器件，而不需要对整个器件进行热处理。通常情况下，接头的微观结构和性能会对接头的性能产生很大的影响。本论文将对RE_2O_3-Al_2O_3-SiO_2(RE：Sc，Yb，Ho，Dy，Y，ND)微晶玻璃焊料进行制备、表征和测试。在该项目中，将对激光加工特殊条件下接头内部的结构形成进行彻底的调查和表征。这些研究包括基本的技术考虑，以及对控制焊料-碳化硅-相互作用的机制和焊料材料中发生的结晶过程的深入的结构、热机械、热力学和动力学分析。在此基础上，节点结构将根据其各自的应用进行量身定做。在连接过程中准确控制焊料的结晶，应允许连接的器件在高达1250°C的温度下应用。该项目的结果将支持开发用于碳化硅基器件密封的耐高温玻璃。它们可用于微电子和传感器应用，以及医疗和光学专用玻璃的开发，用于微晶玻璃环境屏障涂层，以及用于碳化硅、氮化硅和SiAlON基材料的液相烧结。

Laser-supported soldering allows the efficient manufacturing of joined SiC-based devices without thermal treatment of the complete devices. In general, the properties of joined components will be significantly influenced by the microstructure and the properties of the joint.Glass-ceramic solders of the type RE2O3-Al2O3-SiO2 (RE: Sc, Yb, Ho, Dy, Y, Nd) will be synthesized, characterized and tested. Within the project, the structure formation inside the joint under the particular conditions of laser processing will be thoroughly investigated and characterized. These investigations include fundamental technological considerations as well as in-depth structural, thermo-mechanical, thermodynamic and kinetic analyses of the mechanisms governing the solder-SiC-interaction and of the crystallization processes occurring in the solder material. On this basis, joint structures will be tailored to their respective application. Accurately controlling the crystallization of the solder materials during the joining process should allow an application of the joined devices at temperatures up to 1250 °C.The results of this project will support the development of high temperature resistant glasses for the hermetic sealing of SiC-based devices. These can be used in microelectronic and sensor applications as well as for the development of special glasses for medical and optical usage, for glass-ceramic environmental barrier coatings and for the liquid phase sintering of SiC-, Si3N4- and SiAlON-based materials.