Objectives

The aim of this study was to characterize the microstructure of two zirconia-reinforced lithium silicate (ZLS) glass-ceramics and evaluate their mechanical properties before and after the crystallization firing process (CFP).

Methods

Field emission-scanning electron microscope (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses were performed for microstructural characterization. To evaluate the pattern of crystallization and the molecular composition of ZLS glass-ceramics, was used X-ray diffraction (XRD). Vickers hardness, fracture toughness by the indentation method, and biaxial flexural strength were also measured. One hundred and forty ceramic discs were produced (diameter = 12 mm; thickness = 1.2 mm) and allocated among four groups (n = 30): Sfir, Sunf-ZLS Vita Suprinity; and Cfir and Cunf-ZLS Celtra Duo; fired and unfired, respectively. Statistical analysis was performed and Weibull failure probabilities were calculated.

Results

Cfir showed the highest characteristic strength (251.25 MPa) and hardness (693.333 ± 10.85 GPa). Conversely, Sunf presented the lowest characteristic strength (106.95 MPa) and significantly lowest hardness (597.533 ± 33.97 GPa). According to Weibull analysis, Sunf had the highest structural reliability (m = 7.07), while Sfir presented the lowest (m = 5.38). The CFP was necessary to crystallize zirconia in the partially crystallized ZLS glass-ceramics. Sfir had a lower percentage of crystallized zirconia than did Cfir. Fractographic analyses showed that all failures initiated from an inherent critical defect in Sunf and from processing defects in the remaining groups.

Significance

The CFP had a direct influence on the flexural strength and microstructural characteristics of both ZLS materials.

中文翻译：

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结晶烧成工艺对氧化锆增强硅酸锂玻璃陶瓷微结构和抗弯强度的影响

目标

这项研究的目的是表征两种氧化锆增强的硅酸锂（ZLS）玻璃陶瓷的微观结构，并评估其在结晶焙烧过程（CFP）之前和之后的机械性能。

方法

进行了场发射扫描电子显微镜（FE-SEM）和能量色散X射线光谱（EDS）分析，以进行微观结构表征。为了评估ZLS玻璃陶瓷的结晶模式和分子组成，使用了X射线衍射（XRD）。还测量了维氏硬度，通过压痕法的断裂韧性和双轴弯曲强度。制作了一百四十个陶瓷圆盘（直径= 12毫米；厚度= 1.2毫米），并分配给四组（n = 30）：Sfir，Sunf-ZLS Vita Suprinity；Cfir和Cunf-ZLS Celtra Duo；解雇和未解雇。进行统计分析并计算威布尔失效概率。

结果

Cfir表现出最高的特征强度（251.25 MPa）和硬度（693.333±10.85 GPa）。相反，Sunf的特征强度最低（106.95 MPa），硬度最低（597.533±33.97 GPa）。根据Weibull分析，Sunf的结构可靠性最高（m = 7.07），而Sfir的结构可靠性最低（m = 5.38）。CFP是使部分结晶的ZLS玻璃陶瓷中的氧化锆结晶所必需的。与Cfir相比，Sfir的氧化锆百分含量更低。分形分析表明，所有故障都是由Sunf的固有关键缺陷和其余组中的加工缺陷引起的。

意义

CFP对两种ZLS材料的抗弯强度和微观结构特性都有直接影响。