OBJECTIVES To optimize the nucleation mechanism in leucite glass-ceramics to allow more efficacious glass-ceramic manufacture and improvements in microstructure and mechanical reliability. MATERIALS AND METHODS An alumino-silicate glass was designed and synthesized using melt quench methods. The glass was crushed and milled using various milling times (48-93h) and spray drying. Nucleation and growth heat treatment schedules were applied to synthesize glass-ceramics. Glass/glass-ceramic powders and frit specimens were characterized using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), magic angle spinning nuclear magnetic resonance spectroscopy (MAS-NMR) and X-ray diffraction analyses (XRD). Glass-ceramic specimens were tested using the biaxial flexural strength test (BFS). RESULTS Application of defined nucleation heat treatments resulted in the synthesis of Na/Ca titanates. NMR indicated changes to the 23Na glass spectra in the nucleated glass and TEM/EDX the presence of Na/Ca/Ti domains (<200nm) within the leucite crystals and associated with the nucleation of the leucite phase. XRD confirmed the presence of a bulk leucite phase in the glass-ceramics. SEM/TEM confirmed the crystallization of the leucite phase (65.5-69.3%) in a thermally matched glass, in conjunction with the nano Na/Ca titanate phase. The leucite glass-ceramics resulted in a high BFS (255-268MPa), with reduction in powder milling time prior to heat treatments having no significant effect on flexural strength and reliability (p>0.05). SIGNIFICANCE Na/Ca titanates were synthesized in leucite glass-ceramics for the first time and associated with its nucleation and efficacious growth. This nucleation optimization provides opportunities for more efficient manufacturing and microstructural/mechanical reliability improvements. Improved synthesis of high strength/reliable leucite glass-ceramics is useful for construction of esthetic minimally invasive restorations.

中文翻译：

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新型白云石玻璃陶瓷的成核功效和抗弯强度。

目的优化白云石玻璃陶瓷的成核机理，以更有效地制造玻璃陶瓷，并改善微结构和机械可靠性。材料与方法设计了铝硅酸盐玻璃，并采用熔融淬火法进行了合成。使用各种研磨时间（48-93h）将玻璃压碎和研磨并喷雾干燥。将成核和生长热处理方案用于合成玻璃陶瓷。使用差示扫描量热法（DSC），透射电子显微镜（TEM），能量色散X射线光谱（EDX），魔角旋转核磁共振波谱（MAS-NMR）和玻璃/玻璃陶瓷粉末和玻璃料样品进行表征X射线衍射分析（XRD）。使用双轴弯曲强度测试（BFS）测试玻璃陶瓷样品。结果应用确定的成核热处理可合成钛酸Na / Ca。NMR表明在有核玻璃和TEM / EDX中23Na玻璃光谱的变化，白云母晶体内存在Na / Ca / Ti域（<200nm），并与白云母相成核有关。XRD证实在玻璃陶瓷中存在块状白云石相。SEM / TEM证实与纳米Na / Ca钛酸盐相一起在热匹配玻璃中结晶出白云石相（65.5-69.3％）。白云石玻璃陶瓷的BFS较高（255-268MPa），热处理前的粉末研磨时间减少，对弯曲强度和可靠性没有显着影响（p> 0.05）。意义钛酸钠/钙钛酸酯是首次在白云石玻璃陶瓷中合成的，并且与其成核和有效生长有关。这种成核优化为更有效的制造和微结构/机械可靠性的改进提供了机会。高强度/可靠的白云石微晶玻璃合成的改进可用于构建美观的微创修复体。