Improved performances of lithium disilicate glass-ceramics by seed induced crystallization
Ting Zhao, Mei-Mei Lian, Yi Qin, Jianfeng Zhu, Xingang Kong, Jianfeng Yang
Abstract
Abstract Self-reinforced lithium disilicate (Li 2 Si 2 O 5 , LD) glass-ceramics were hot pressing sintered by introducing 5 wt% Li 2 Si 2 O 5 crystal seeds into two different glass compositions of SiO 2 -Li 2 O-P 2 O 5 -ZrO 2 -Al 2 O 3 -K 2 O-La 2 O 3 (7C LD) and SiO 2 -Li 2 O-K 2 O-La 2 O 3 (4C LD). The results show that the seeds play an important role in the crystallization inducement, and microstructural and property improvement of the glass, especially for the glass powder without the nucleating agent of P 2 O 5 . The microstructure features a wider bimodal grain size distribution with large rod-like crystals epitaxially grown along the seeds and small crystals nucleated from the glass powder itself, contributing to the improvement of the performance especially the fracture toughness. The specimen of 4C LD glass with the addition of 5 wt% Li 2 Si 2 O 5 seeds exhibited the best comprehensive properties with a good flexural strength (396±7 MPa), improved fracture toughness (3.31±0.19 MPa·m 1/2 ), and comparable translucency as IPS e.max. This research provides a new idea and method for the improvement of the fracture toughness of lithium disilicate glass-ceramics without affecting its aesthetic appearance, and lays the foundation for its clinical applications.