Improving bending strength of LTCC materials with low dielectric loss by structural design

Abstract

The flake alumina filler is added to improve the bending strength in BaZrO₃ (BZ)/BaO-MgO-ZnO-SiO₂-B₂O₃ (BBSMZ) glass for the application of low temperature co-fired ceramics. The effects of flake alumina filler for BaZrO₃/BaO-MgO-ZnO-SiO₂-B₂O₃ on phase, microstructure, dielectric and mechanical property are studied. With the increase of flake Al₂O₃ content, flake Al₂O₃ phase appears, BaZrO₃, BaZr(BO₃)_2, BaZn₂Si₂O₇ phase decreases, dielectric constant decreases and dielectric loss increases. By adding flake Al₂O₃, the mechanical strength of the material increases. Under the same sintering conditions, the bending strength (205 MPa) of the laminated sample increased by nearly 60% compared with the same content flake alumina block sample (124 MPa), and increased by 162% compared with the sample without flake alumina (78 MPa). BZ-BBSMZ-5 wt% flake Al₂O₃ ceramic sintered satisfactorily at 940 °C with tanδ = 4.82*10^–4 (10 GHz), ε_r = 11.66. The bending strength of the sample is 205 Mpa.