Engineering Ceramics Department, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
Engineering Ceramics Department, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
Acta Biomater. 2015 Jan;11:477-87. doi: 10.1016/j.actbio.2014.09.009. Epub 2014 Sep 16.
The combined effect of alumina and silica co-doping on the ageing resistance of 3Y-TZP bioceramics was investigated. In order to differentiate between the distinct contributions of two dopants to the overall resistance to low-temperature degradation (LTD), specimens were prepared by infiltration of silica sol into pre-sintered 3Y-TZP pellets, produced from commercially available powders, which were alumina-free or contained 0.05 and 0.25 wt.%. After sintering, specimens were exposed to accelerated ageing in distilled water at 134°C for 6-48 h. X-ray diffraction was applied to quantify the tetragonal-to-monoclinic (t-m) phase transformation associated with the LTD, while a focused ion beam-scanning electron microscopy technique was employed to study the microstructural features in the transformed layer. The results showed that the minor alumina and/or silica additions did not drastically change the densities, grain sizes or mechanical properties of 3Y-TZP, but they did significantly reduce LTD. The addition of either alumina or silica has the potential to influence both the nucleation and the propagation of moisture-induced transformation, but in different ways and to different extents. The co-doped ceramics exhibited predominantly transgranular fracture, reflecting strong grain boundaries (limiting microcracking of the transformed layer), for alumina doping, and rounded grains with a glassy phase at multiple grain junctions (reducing internal stresses) for silica-doped material. These two additives evidently have different dominant mechanisms associated with the deceleration of LTD of 3Y-TZP, but their combination increases resistance to ageing, importantly, without reducing the fracture toughness of this popular biomaterial.
研究了氧化铝和二氧化硅共掺杂对 3Y-TZP 生物陶瓷抗老化性能的综合影响。为了区分两种掺杂剂对低温降解（LTD）整体抵抗力的不同贡献，通过将硅溶胶渗透到由市售粉末制成的无氧化铝或含有 0.05 和 0.25wt.%氧化铝的预烧结 3Y-TZP 颗粒中，制备了样品。烧结后，将样品在 134°C 的去离子水中进行加速老化处理，时间为 6-48 小时。X 射线衍射用于定量测量与 LTD 相关的四方相到单斜相（t-m）相变，而聚焦离子束扫描电子显微镜技术用于研究转化层的微观结构特征。结果表明，少量的氧化铝和/或二氧化硅添加并没有显著改变 3Y-TZP 的密度、晶粒尺寸或力学性能，但它们确实显著降低了 LTD。氧化铝或二氧化硅的添加都有可能影响湿气诱导相变的成核和传播，但方式和程度不同。共掺杂陶瓷表现出主要的穿晶断裂，反映出强烈的晶界（限制转化层的微裂纹），对于氧化铝掺杂，以及在多个晶粒连接处具有玻璃相的圆形晶粒（降低内应力）对于二氧化硅掺杂材料。这两种添加剂显然与 3Y-TZP 的 LTD 减速有关，具有不同的主要机制，但它们的组合增加了抗老化能力，重要的是，不会降低这种流行生物材料的断裂韧性。
