Effect of composition on crystallization behavior of La₂O₃- B₂O₃-CaO glass-ceramics

The forming region of La2O3-B2O3-CaO (LBC) glass-ceramics sintering aid was investigated. The effects of CaO content and the La/B ratio on the crystallization behavior and sintering behavior were studied. The results demonstrated that the glass forming region of LBC glass-ceramics was La2O3:0-27 mol%; B2O3:46-83 mol%; CaO: 0-44 mol%. The addition of CaO which changed the crystallization tendency of glass-ceramics could effectively reduce the glass transition temperature (Tg ) and the softening temperature (Ts ). The crystallization temperature (Tp ) increased at first and then decreased with the increase of CaO content. The increase of the La/B ratio could effectively weaken the network continuity and structural strength leading to the glass transition temperature (Tg ), the softening temperature (Ts ) and the crystallization temperature (Tp) decreased. When the CaO content was 20 mol% and the ratio of La/B was 0.3, the LBC glass-ceramics had a good thermal stability (ΔT= 139 °C) and a low softening temperature (Ts =662 °C) which showed the potential to be used in the sintering aid for LTCC applications.