CoO-doped MgO–Al2O3–SiO2-colored transparent glass–ceramics with high crystallinity

Abstract

To obtain CoO-doped MgO-Al2O3-SiO2 (MAS)-colored transparent glass–ceramics with high crystallinity, the glass with the composition 21MgO–21Al2O3–54SiO2–4B2O3–0.2CoO (in mol %) was prepared by conventional melt quenching technique and subsequently thermal treated at several temperatures. The crystallization behavior of the glass, the precipitated crystalline phases and crystallinity were analyzed by X-ray diffraction (XRD). The microstructure of the glass–ceramics was characterized by field emission scanning electron microscopy (FSEM). The transmittance of glass–ceramic was measured by UV spectrophotometer. The results show that a large amount of α-cordierite (indianite) with nano-size was precipitated from the glass matrix after treatment at 1020 °C for 3 h. The crystallinity of the transparent glass–ceramic reached up to 97%. Meanwhile, the transmittance of the glass–ceramic was 74% at 400 nm with a complex absorption band from 450 nm to 700 nm. In addition, this colored transparent glass–ceramic possessed lower density (2.469 g/cm3), lower thermal expansion coefficient (1.822 × 10−6 /℃), higher Vickers hardness (9.1 GPa) and higher bending strength (198 MPa) than parent glass.