Al2O3-Al2O3 and Al2O3-Ti Solder Joints-Influence of Ceramic Metallization and Thermal Pretreatment on Joint Properties

In this work, Al2O3–Al2O3 and Al2O3–Ti solder joints intended for space applications were realized by applying metallic multilayers both on Ti and on polycrystalline Al2O3 substrates to ensure wetting during the soldering process. The eutectic Au-12Ge (wt%) alloy with a melting point of 361°C was used as solder material and two different multilayer systems on the ceramic (Cr-Ni/Ti-W/Au,Ti/Pt/Au) were investigated. The influence of different thermal pretreatments of the Al2O3 plates on the multilayer properties, the interface reactions during soldering and the mechanical properties were studied using Glow-Discharge Optical Emission Spectroscopy (GDOES), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and a shear test device. It is shown that joints with a good quality can be produced at a soldering temperature of 400°C, whereas their properties and fracture behavior are strongly dependent on the metallization layer properties and the thermal pretreatments.