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

• Applicants: Professor Dr.-Ing. Wolfgang Lippmann; Professor Dr. Hans Jürgen Seifert
• Subject Area: Glass, Ceramics and Derived Composites ; Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: from 2012 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 220880041

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.

• DFG Programme: Research Grants