Different microstructure BaO-B2O3-SiO2 glass/ceramic composites depending on high-temperature wetting affinity

In this work, we propose a simple but effective method to fabricate BaO-B2O3-SiO2 glass/ceramic composites with different microstructures that depend on the high-temperature wetting affinity. The experimental results showed that the wetting affinity between oxide ceramic and the BaO-B2O3-SiO2 glass matrix could strongly affect the driving force of densification and crystallization and finally the microstructure of the glass/ceramic composites. It was found that suitable amounts of alumina powders could obviously increase the driving force for sintering of glass by increasing the capillary pressure. In this case, the contact angle between alumina and glass matrix is about 24 at high temperature and a densified and homogeneous microstructure of glass/alumina composite was obtained. On the contrary, rutile powders additive was found to result in higher phase separation and crystallization during the sintering of glass/rutile composites. In this case, the contact angle between rutile and glass matrix is about 124 at high temperature, and the sintered body has a lower dielectric loss than the sample with alumina additive. Therefore, the microstructure and dielectric property of glass/ceramic composites could be controlled by adjusting the ceramic composition and wetting affinity between ceramic additive and glass matrix in our study. (C) 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.