Glass structure, crystallization kinetics and dielectric properties of CeO2-added CaO-B2O3-SiO2 glass system

This work investigated the effects of CeO2 contents on structure, crystallization behavior and dielectric properties of CaO-B2O3-SiO2 glass composition. The MAS-NMR results showed that B occurred as B-IIIa, B-IIIs and B-IV species and Si presented as Q(2), Q(3) and Q(4) units in the glasses. As the increase of CeO2 content, the relative amounts of B-IV and B-IIIs unit decreased while the B-IIIa units increased, and the amounts of Q(4) and Q(2) units increased while the Q(3) unit decreased. With increasing CeO2 content, the value of T-g decreased from 743 degrees C to 717 degrees C, the activation energy for CaSiO3 first increased and then decreased. For glass-ceramics samples sintered at 825 degrees C, all samples had the crystalline phases of CaSiO3, CaB2O4, Ca2SiO4. In addition, the samples with CeO2 content more than 1mol% had CeO1.695 phase, which changed to be the main crystalline phase when the content of CeO2 increased up to 10mol%. The epsilon(r) of the glass-ceramic samples with CeO2 content x6 showed an ascend trend in total, and decreased sharply to 4.1 for the sample with x=10. However, the dielectric loss tan would not change significantly with the increasing of CeO2 content. The samples with 1mol% CeO2 sintered at 825 degrees C owned epsilon(r) of 5.4, tan of 0.9x10(-3), and CTE of 7.8x10(-6)/K. The results indicated that CaO-B2O3-SiO2 with CeO2 glass-ceramics could be a potential LTCC substrate material.