Microstructure and properties of YIG/YIG magnetic homogenization joint fabricated by a novel Bi₂O₃–B₂O₃–NiO–Fe₂O₃ magnetic glass

Aiming at mechanical and electromagnetic demands for yttrium iron garnet ferrite (YIG) integrated structure, a novel Bi₂O₃–B₂O₃–NiO–Fe₂O₃ (BBNF) low-melting magnetic glass braze was designed. Nearly magnetic homogenization YIG/YIG joints were fabricated successfully. In-situ magnetic microcrystalline phases NiFe₂O₄ and Ni₂FeO₄ with good mechanical property precipitated in the brazing seam. The magnetization performance of YIG/YIG joints was significantly promoted. Merely 10 % difference of the magnetization strength per unit mass of the joints to YIG base materials was achieved. The joint shear strength reached its maximum of 79 MPa due to the enhancement of the microcrystalline phases. It is significant for improving both structural stability and functional reliability of the microwave devices for long-term service.