Sintering, densification and crystallization of Ca-Al-B-Si-O glass/Al_2O_3 composites for LTCC application

摘要

Ca-Al-B-Si-O glass/Al_2O_3 composites were prepared based on the borosilicate glass powders (D_(50) = 2.84) and Al_2O_3 ceramic powders (D_(50) = 3.26), and the sintering, densification, crystallization of samples were investigated. The shrinkage of sample starts to have a sharp increase at 600 ℃. The shrinkage of sample starts to have a further rapid increase after the glass softening temperature of about 713 ℃. Glass/Al_2O_3 composites can be sintered at 875 ℃/15 min and exhibit better properties of a relative density of 98.4 %, a λ value of 2.89 W/mK, a ε_r value of 7.82 and a tan δ value of 5.3 × 10~(-4). The interface between glass and Al_2O_3 grains and the interface between anorthite and glass phase depicts a good compatibility according to transmission electron microcopy test. It is the low sintering temperature, high density and good compatibility with Ag electrodes that, guarantee borosilicate glass/Al_2O_3 composites suitable for low temperature co-fired ceramic materials.