Effects of Cr2O3 additive on crystallization behavior of MgO-Al2O3-SiO2-TiO2 glass-ceramics

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 7x10(-4).