Abstract:

The crystallization behavior of MgO-Al₂O₃-SiO₂-TiO₂ glasses containing Cr₂O₃ was investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The crystallization activation energy (E) was also calculated by Ozawa and Kissinger methods. The results show that the initial precipitated phase and the main crystal phase are not changed by the Cr₂O₃ addition. Meanwhile, the glass transition temperature (T_g) increases and the crystallization apparent activation energy decreases. As a result the E values of cordierite is decreased, the formation of cordierite crystals is promoted. The glass-ceramic obtained by crystallization of the glass has dielectric constant around 5.5, and dielectric loss less than 7×10^-4.

Key words: α-cordierite, glass-ceramics, crystallization activation energy, dielectric property