牙科用可切削云母基玻璃陶瓷析晶行为研究

Crystallization behavior of machinable mica based glass-ceramics for dental application

目的:采用阶梯烧结法制备K2O-MgO-Al2O3-SiO2-F系列玻璃陶瓷,分析不同热处理工艺对所制玻璃陶瓷性能的影响。方法:通过X射线衍射(XRD)、扫描电子显微镜(SEM)、背散射(BSE)及抗弯强度测试,研究氟硅云母玻璃陶瓷的析晶行为特点。结果:680℃核化1 h后,若在1 000~1 120℃之间晶化,则析出主晶相为四氟硅云母,晶体形状由颗粒状逐渐变成立方状或扁平状。陶瓷在大于1 160℃晶化出现晶体熔化。结论:680℃核化1 h后,1 040℃析出的云母晶体符合材料的微观要求,过高的温度不利于云母晶体的析出;二次融入3%的四方氧化锆多晶体(Y-TZP)完全熔解于K2O-MgO-Al2O3-SiO2-F玻璃系统中。

Objective ： To study the effects of various heat-treatments on the crystallization behavior of the K2 O- MgO- A12 03- SiO2- F system glass-ceramics prepared by step sintering method. Methods： The phase composilion and the microstructure changes in the ceramics were observed using X-ray diffraction （XRD） , scanning electron microseopy（SEM） and back scattered electron （BSE）. In parallel, the flexural strength（FS） of the ceramics were investigated by three-point bending strength evaluation. Results： After nucleating at 680 ℃ for 1 h the fluorosilicic mica presented as the main crystal phases by a sintered bodies crystallization at the temperature range of 1 000 - 1 120℃ , and the crystal was gradually changed from particle-shape to cubic-shape or fat-shape. However, the crystal melted when the crystallization temperature was higher than 1 160 ℃. As the sintering temperature increased from 1 040 ℃ to 1 200 ℃, the FS（MPa） was decreased from 136.0 ± 91 to 78.6 ± 11.4. Conclusion ： F^llowing nucleating at 680 ℃ for 1 h the mica crystal sintered at I 040 ℃ has the optimal microstructure for dental application. The mica crystallizing may be degraded when the sintered temperature is remarkably high. Besides, 3% Y-TZP can melt in the K20-MgO-Al2O3-SiO2-F system glass-ceramics completely.