Effect of nucleating agents on microstructure and mechanical properties of SiO₂-Al₂O₃-ZrO₂ glass-ceramics

Abstract

SiO₂-Al₂O₃-ZrO₂ glasses with different nucleating agents were crystallized under special processing schedule. The microstructure and mechanical properties of the glass-ceramics in SiO₂-Al₂O₃-ZrO₂ system were investigated by differential scanning calorimetry, scanning electron microscopy, X-ray diffraction and three-point bending method. The results show that ZrO₂ is not an effective nucleating agent in SiO₂-Al₂O₃-ZrO₂ system, while TiO₂ is effective for the separation of spinel, and P₂O₅ facilitates solubility of ZrO₂ in glass and crystallization. The main crystalline phases of the glass-ceramics are spinel, anorthite and tetragonal zirconia. With the increase of ZrO₂ content in the glass, glass-ceramics show higher bending strength (120 MPa) than others.

Keywords

glass-ceramics / SiO₂-Al₂O₃-ZrO₂ system / microstructure / mechanical property