Nakonieczny Damian S, Paszenda Zbigniew K, Basiaga Marcin, Radko Tomasz, Drewniak Sabina, Podwórny Jacek, Bogacz Wojciech
Department of Biomaterials and Medical Devices Engineering, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland.
Institute for Chemical Processing of Coal, Zabrze; Poland.
Acta Bioeng Biomech. 2017;19(2):21-30.
High purity, fine crystalline, degradation-free at low temperature powders have attracted special interest in CAD/CAM prosthetic dentistry full ceramic restorations. This study reports the preparation and characterisation of zirconia-ceria (0.9 ZrO2 0.1 CeO2) powders. Materials were obtained from zirconium-n-alkoxide and cerium nitrate hexahydrate in the pH 2-4 and 8-10.
Zirconia- ceria powders were obtained with the sol-gel method in a humid-free environment. Thermal analysis (TGA/DTA) of the as-prepared materials was made for an assessment of its behaviour at elevated temperatures. Specimens were dried at 80 °C and calcinated in two stages: at 300 °C with soaking time 2.5 h and 850 °C with holding time 2.5 h, in order to evaluate the phase transformations. Thermal analyses of the as-dried powders were made for an assessment of its thermal behaviour during heat treatment up to 1000 °C. By X-ray diffraction (XRD), polymorphs of ZrO2 were identified. Additionally, scanning electron microscopy (SEM) and laser particle size distribution (PSD) were involved for characterisation of morphology of the powders.
A correlation between the pH of the colloidal system and the morphology of the as-obtained powders were found. Based on analysis (SEM, PSD), structures were identified known as soft and hard agglomerates.
It can be stated that differences found between powder morphology were dependent on the value pH used, which can be crucial for powder densification during sintering and compacting green bodies which, as a consequence, may be crucial for the lifetime of zirconia prostheses. Correlations between phase composition and pH are difficult to grasp, and require further, more sophisticated, studies.
高纯度、细晶型且在低温下无降解的粉末在计算机辅助设计/计算机辅助制造（CAD/CAM）口腔修复全瓷材料中引起了特别关注。本研究报告了氧化锆 - 二氧化铈（0.9ZrO₂ - 0.1CeO₂）粉末的制备及表征。材料由锆醇盐和六水硝酸铈在pH值为2 - 4和8 - 10的条件下获得。
在无湿环境中通过溶胶 - 凝胶法获得氧化锆 - 二氧化铈粉末。对所制备材料进行热分析（热重分析/差示热分析，TGA/DTA）以评估其在高温下的行为。样品在80°C下干燥，并分两个阶段煅烧：300°C下保温2.5小时和850°C下保温2.5小时，以评估相变情况。对干燥后的粉末进行热分析以评估其在高达1000°C热处理过程中的热行为。通过X射线衍射（XRD）确定ZrO₂的多晶型物。此外，还采用扫描电子显微镜（SEM）和激光粒度分布（PSD）来表征粉末的形态。
发现胶体体系的pH值与所得粉末的形态之间存在相关性。基于分析（SEM、PSD），确定了软团聚体和硬团聚体结构。
可以说，粉末形态的差异取决于所使用的pH值，这对于烧结和压实生坯过程中的粉末致密化可能至关重要，进而可能对氧化锆假体的寿命至关重要。相组成与pH值之间的相关性难以把握，需要进一步开展更复杂的研究。
