Jiang Li, Zhao Yong-qi, Zhang Jing-chao, Liao Yun-mao, Li Wei
State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2010 Jun;45(6):376-80.
To study the effects of alumina content on sintered density, mechanical property and translucency of zirconia nanocomposite all-ceramics.
Specimens of zirconia nanocomposite all-ceramics were divided into five groups based on their alumina content which are 0% (control group), 2.5%, 5.0%, 7.5% and 10.0% respectively. The sintered densities were measured using Archimedes' method. Specimens' bending strengths were measured with three-point bending test (ISO 6872). The visible light transmittances were measured with spectrophotometric arrangements and the fractured surfaces were observed using scanning electron microscope (SEM).
The control group of pure zirconia could be sintered to the theoretical density under pressure-less sintering condition. The bending strength was (1100.27 ± 54.82) MPa, the fracture toughness was (4.96 ± 0.35) MPa×m(1/2) and the transmittance could reach 17.03%. The sintered density and transmittance decreased as alumina content increased from 2.5% to 10%. However, the fracture toughness only increased slightly. In all four alumina groups, the additions of alumina had no significant effect on samples' bending strengths (P > 0.05). When the content of alumina was 10%, fracture toughness of specimens reached (6.13 ± 0.44) MPa×m(1/2) while samples' transmittance declined to 6.21%. SEM results showed that alumina particles had no significant effect on the grain size and distribution of tetragonal zirconia polycrystals.
Additions of alumina to yttria-tetragonal zirconia polycrystals could influence its mechanical property and translucency. Additions of the other phase to zirconia ceramics should meet the clinical demands of strength and esthetics.
研究氧化铝含量对氧化锆纳米复合全瓷材料烧结密度、力学性能及半透明度的影响。
根据氧化铝含量将氧化锆纳米复合全瓷材料试样分为五组，分别为0%（对照组）、2.5%、5.0%、7.5%和10.0%。采用阿基米德法测量烧结密度。通过三点弯曲试验（ISO 6872）测量试样的弯曲强度。用分光光度计装置测量可见光透过率，并用扫描电子显微镜（SEM）观察断裂表面。
纯氧化锆对照组在无压烧结条件下可烧结至理论密度。弯曲强度为（1100.27±54.82）MPa，断裂韧性为（4.96±0.35）MPa×m(1/2)，透过率可达17.03%。随着氧化铝含量从2.5%增加到10%，烧结密度和透过率降低。然而，断裂韧性仅略有增加。在所有四个氧化铝组中，氧化铝的添加对样品的弯曲强度没有显著影响（P>0.05）。当氧化铝含量为10%时，试样的断裂韧性达到（6.13±0.44）MPa×m(1/2)，而样品的透过率降至6.21%。SEM结果表明，氧化铝颗粒对四方氧化锆多晶体的晶粒尺寸和分布没有显著影响。
向钇稳定四方氧化锆多晶体中添加氧化铝会影响其力学性能和半透明度。向氧化锆陶瓷中添加其他相应满足强度和美观的临床要求。
