Effect of TiO2 on the structure and mechanical properties of SiO2-Al2O3-MgO glasses
Résumé
The Silicate glasses in TiO2/SiO2-Al2O3-MgO system doping with 0-1.8 wt% TiO2 were prepared by the conventional melt quenching technique, and the effects of TiO2 on the density, bending strength, compressive strength, compression modulus and structural stability were investigated. When the content of TiO2 is less than 1.5 wt% (mass fraction), the density, bending strength, compressive strength and compression modulus increase with the increasing of TiO2 content, and the optical band gap decreases with the TiO2 content increasing. As the content of TiO2 is more than 1.5 wt%, the density, bending strength, compressive strength and compression modulus decrease with the increasing of TiO2 content, and the optical band gap increases with the increasing of TiO2 content. When the content of TiO2 is 1.5 wt%, the mechanical properties of the TiO2/SiO2-Al2O3-MgO system is excellent, and the bending strength, compressive strength, compression modulus and optical band gap of the glasses is 110.36 MPa, 240.18 MPa, 115.03 GPa and 3.75 eV, respectively. The addition of TiO2 reduces the numbers of the non-bridging oxygen in the glass network structure, increasing the structural stability of the investigated glasses. So the network structure of the isolated island is rejoined, which significantly improve the mechanical properties of the glass. However, excessive TiO2 force its structure of the bridge oxygen bond to generate non-bridging oxygen, which significantly reduces the structural stability and mechanical properties of the investigated glasses. © 2017, Chinese Society for Composite Materials. All right reserved.