Effect of increasing the Al<sub>2</sub>O<sub>3</sub> content on the phase formation and mechanical properties of lithium disilicate glass-ceramics
Wilaiwan Leenakul, Arnon Kraipok
Abstract
Abstract Lithium disilicate glass ceramics with improved properties were prepared via a thermal treatment method by varying its composition. This study aims to investigate the influence of the concentration of Al 2 O 3 additive oxides on the phase formation and mechanical properties of lithium disilicate glass ceramics prepared by conventional method. The Al 2 O 3 concentration used are 3.0, 4.5, and 6.0 mol% for LCA1, LCA2, and LCA 3, respectively. As the content of Al 2 O 3 increased the glass transition temperature (T g ), the crystallization temperature (T c ), phase formation, and mechanical properties of lithium disilicate glass ceramics varied considerably, demonstrating the substantial effect of Al 2 O 3 . After heat treatment at 600 °C and 800 °C for 1 h, the x-ray diffraction results showed that the major phase in all the glass-ceramic samples was Li 2 Si 2 O 5 and the minor phases were CeO 2 , LiAlSi 3 O 8 , quartz, and Li 2 SiO 3 . For the lowest content of Al 2 O 3 , the highest flexural strength and Vickers hardness were obtained as 188.34 MPa and 776 HV, respectively. These results were attributed to the interlocking microstructure of rod-like Li 2 Si 2 O 5 in the LCA1 sample.