The low temperature sealing of Kovar alloy to DM305 electronic glass was realized by using lead-free glass solder of the Bi₂O₃-ZnO-B₂O₃ system in atmospheric environment. The sealing process was optimized by pre-oxidation of Kovar alloy and low temperature founding of flake glass solder. The effects of sealing temperature and holding time on the properties of sealing joint were studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), etc. The results showed that the pre-oxidized Kovar alloy and DM305 electronic glass were successfully sealed with flake glass solder at the sealing temperature of 500 °C for 20 min. Meanwhile, the joint interface had no pores, cracks, and other defects, the shear strength was 12.24 MPa, and the leakage rate of air tightness was 8 × 10⁻⁹ Pa·m³/s. During the sealing process, element Bi in glass solder diffused into the oxide layer of Kovar alloy and DM305 electronic glass about 1 μm, respectively.

The joining methods of Aluminum matrix composites reinforced with SiC particles (SiC_p/Al MMCs) are a challenge during the manufacturing process due to the significant differences between SiC particles and base aluminum in terms of both physical and chemical properties. Micro-nano brazing filler metal Al-17.0Cu-8.0Mg fabricated by melt-spinning technology was employed to deal with the joining problem of 55 vol.% SiC_p/ZL102 composites in this work. The result indicated that the foil-like brazing filler metal contained uniformed cellular nano grains, with a size less than 200 nm. The solidus and liquidus temperatures of the foil-like brazing filler metal decreased by 4 °C and 7 °C in comparison with the values of the as-cast brazing filler metal due to the nanometer size effect. The maximum joint shear strength of 98.17 MPa achieved with a brazing temperature of 580 °C and holding time of 30 min was applied in vacuum brazing process. The width of the brazing seam became narrower and narrower with increasing brazing temperature owning to the strong interaction between the micro-nano brazing filler metal and 55 vol.% SiC_p/ZL102 composites. The fracture morphology of the joint made at a brazing temperature of 580 °C was characterized by quasi-cleavage fracture. After brazing, the chemical concentration gradient between the brazing filler metal and base material disappeared.

SiC-particulate-reinforced aluminum matrix composites (SiCp/Al MMCs) are widely used in the aerospace field due to their high specific stiffness and strength, low thermal expansion coefficient, and good radiation resistance. In the process of application and promotion, there is a connection problem between the aluminum matrix composites and electronic glass. In this work, the lead-free SiO₂-B₂O₃-Na₂O glass filler was used to seal 65 vol.% SiCp/ZL102 composites and DM305 electronic glass in an atmospheric environment. The effects of the sealing temperature on the properties of the joints were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Additionally, the causes of defects and the fracture mechanisms of the joints were analyzed. The results showed that the glass filler and base material were connected through a dual mechanism of an Al, Na, Si, and O element diffusion reaction and a mechanical occlusion. At a sealing temperature of 540 °C and a holding time of 30 min, the joint interface was dense and crack-free. Meanwhile, the average shear strength reached 13.0 MPa, and the leakage rate of air tightness was 1 × 10⁻⁹ Pa·m³/s. The brittle fracture features were revealed by the step-like morphology of the fracture, which originated from the brazing seam and propagated into the pore. The crack gradually propagated into the base material on both sides as the fracture area expanded, ultimately resulting in a fracture.