Abstract: Cordierite silicon glass-ceramics with different nucleating agents were prepared by melting. The effects of different nucleating agents on the crystallization and properties of glass-ceramics were studied by DSC, XRD, FE-SEM, UV-VIS-NIR and other test methods, and the crystallization kinetics of glass-ceramics with different nucleating agents were analyzed using the classical kinetic equation (Johnson-Mehl-Avrami). The results indicate that the crystallization mechanism of glass-ceramics with P₂O₅ or P₂O₅+ZrO₂ as nucleating agent is controlled by surface crystallization. However, the glass-ceramics with P₂O₅+ZrO₂+TiO₂ as nucleating agent has the tendency to be bulk crystallization. With the crystallization temperature increases from 950 ℃ to 980 ℃, the μ-cordierite in the three groups of glass-ceramics begins to transform into α-cordierite. While the introduction of TiO₂ increases the α-cordierite content, the precipitated crystals become dense. With the extension of crystallization time, compared with other nucleating agent, the glass-ceramics with P₂O₅+ZrO₂+TiO₂ as nucleating agent obtain higher crystallinity within the same crystallization time, the increase of α-cordierite content significantly improves the mechanical properties of glass-ceramics, but decreases the light transmittance. Under the heat treatment system of 800 ℃/10 h+980 ℃/3 h, the elastic modulus of glass-ceramics with P₂O₅+ZrO₂+TiO₂ as nucleating agent reaches 103 GPa, the fracture toughness is 1.27 MPa·m^1/2 and the light transmittance is 82.3%, which meet the performance requirements of mobile terminals.

Key words: MgO-Al₂O₃-SiO₂, cordierite, nucleating agent, transparent glass-ceramics, elastic modulus, crystallization kinetics