Zhang Fei, Inokoshi Masanao, Batuk Maria, Hadermann Joke, Naert Ignace, Van Meerbeek Bart, Vleugels Jef
KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, Belgium.
KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven & Dentistry, University Hospitals Leuven, Belgium; Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8510, Japan.
Dent Mater. 2016 Dec;32(12):e327-e337. doi: 10.1016/j.dental.2016.09.025. Epub 2016 Sep 30.
The aim was to evaluate the optical properties, mechanical properties and aging stability of yttria-stabilized zirconia with different compositions, highlighting the influence of the alumina addition, YO content and LaO doping on the translucency.
Five different Y-TZP zirconia powders (3 commercially available and 2 experimentally modified) were sintered under the same conditions and characterized by X-ray diffraction with Rietveld analysis and scanning electron microscopy (SEM). Translucency (n=6/group) was measured with a color meter, allowing to calculate the translucency parameter (TP) and the contrast ratio (CR). Mechanical properties were appraised with four-point bending strength (n=10), single edge V-notched beam (SEVNB) fracture toughness (n=8) and Vickers hardness (n=10). The aging stability was evaluated by measuring the tetragonal to monoclinic transformation (n=3) after accelerated hydrothermal aging in steam at 134°C, and the transformation curves were fitted by the Mehl-Avrami-Johnson (MAJ) equation. Data were analyzed by one-way ANOVA, followed by Tukey's HSD test (α=0.05).
Lowering the alumina content below 0.25wt.% avoided the formation of alumina particles and therefore increased the translucency of 3Y-TZP ceramics, but the hydrothermal aging stability was reduced. A higher yttria content (5mol%) introduced about 50% cubic zirconia phase and gave rise to the most translucent and aging-resistant Y-TZP ceramics, but the fracture toughness and strength were considerably sacrificed. 0.2mol% LaO doping of 3Y-TZP tailored the grain boundary chemistry and significantly improved the aging resistance and translucency. Although the translucency improvement by LaO doping was less effective than for introducing a substantial amount of cubic zirconia, this strategy was able to maintain the mechanical properties of typical 3Y-TZP ceramics.
Three different approaches were compared to improve the translucency of 3Y-TZP ceramics.
评估不同组成的氧化钇稳定氧化锆的光学性能、力学性能和老化稳定性，重点突出氧化铝添加量、YO含量和LaO掺杂对透明度的影响。
五种不同的Y-TZP氧化锆粉末（3种市售和2种实验改性）在相同条件下烧结，并用Rietveld分析的X射线衍射和扫描电子显微镜（SEM）进行表征。用色差仪测量透明度（每组n=6），从而计算透明度参数（TP）和对比度（CR）。用四点弯曲强度（n=10）、单边V型切口梁（SEVNB）断裂韧性（n=8）和维氏硬度（n=10）评估力学性能。通过在134°C蒸汽中加速水热老化后测量四方相向单斜相转变（n=3）来评估老化稳定性，并用Mehl-Avrami-Johnson（MAJ）方程拟合转变曲线。数据通过单因素方差分析进行分析，随后进行Tukey's HSD检验（α=0.05）。
将氧化铝含量降低至0.25wt.%以下可避免氧化铝颗粒的形成，从而提高3Y-TZP陶瓷的透明度，但水热老化稳定性降低。较高的氧化钇含量（5mol%）引入了约50%的立方氧化锆相，得到了最透明且抗老化的Y-TZP陶瓷，但断裂韧性和强度大幅牺牲。3Y-TZP的0.2mol%LaO掺杂调整了晶界化学性质，显著提高了抗老化性和透明度。尽管LaO掺杂对透明度的提高效果不如引入大量立方氧化锆，但该策略能够保持典型3Y-TZP陶瓷的力学性能。
比较了三种不同的方法来提高3Y-TZP陶瓷的透明度。
