Effect of nucleating agents on microstructure and mechanical properties of SiO_2-Al_2O_3-ZrO_2 glass-ceramics

摘要

SiO_2-Al_2O_3-ZrO_2 glasses with different nucleating agents were crystallized under special processing schedule. The microstructure and mechanical properties of the glass-ceramics in SiO_2 - Al_2O_3 -ZrO_2 system were investigated by differential scanning calorimetry , scanning electron microscopy, X-ray diffraction and three-point bending method. The results show that ZrO_2 is not an effective nucleating agent in SiO_2-Al_2O_3-ZrO_2 system, while TiO_2 is effective for the separation of spinel, and P_2O_5 facilitates solubility of ZrO_2 in glass and crystallization. The main crystalline phases of the glass-ceramics are spinel, anorthite and tetragonal zirconia. With the increase of ZrO_2 content in the glass, glass-ceramics show higher bending strength (120 MPa) than others.