氧化锆基医用牙科修复纳米陶瓷的合成

　　材料及生物工程

　　杨奕，北京汇文中学

　　项目摘要：

　　稀土稳定氧化锆因其具有突出的力学性能和生物相容性，在生物医用领域得到广泛应用。然而，现有体相材料存在着成相温度高、加工难度大等缺点，严重影响了它的应用。

　　本项目针对牙科修复材料的要求，采用二步水热法合成了单分散的、粒径约8 nm的四方相氧化钇稳定氧化锆纳米晶；开发了采用Stöber方法在所制备纳米晶表面包覆厚度约5 nm二氧化硅的工艺；同时扩大合成规模，优化合成条件，使之可以用于工业实验生产。此外，还研究了纳米晶粉体的冷等静压成型方法，获得了满足牙科修复陶瓷材料要求的坯体。

　　本文为工业化合成能够满足生物医用需求的氧化钇稳定氧化锆纳米晶、以及进行表面包覆提供了可行的优化条件。所获工艺路线低耗、绿色，具有先进性。

　　Abstract:

　　Rare earth stabilized zirconia (RESZ) is one of the most important ceramics with unique mechanical, processible, and biocompatible performance. However, the recent industrial process only meets the requirements for producing the bulk materials. Because of the nature of RESZ materials, it is difficult to control the structure and particle size exactly by the solid-state reaction.

　　In this study, the monodisperse, tetragonal-phased yttria stabilized zirconia (YSZ) nanoparticles with ca. eight nm of diameter were fabricated via a two-step hydrothermal reaction. The preparation process was optimized to meet the scale-up in industrial. A thin silica layer of ca. 5 nm was coated onto the as-prepared nanoparticles, which may improve the aesthetic appearance of the ceramic and lower the difficulty of processing, as well as reduce the cost. The silica layer was modified on the YSZ nanoparticles according to Stöber method, and this process can be scaled up to 1 L. The molding and processing of as-prepared nanoparticles are also studied by an isostatical process combined with a sintering treatment.

　　This work provides a method to fabricate monodisperse and tetragonal YSZ nanoparticles with lower cost and environmental-friendly. By optimizing the reaction condition, this process is easy scaled up into industrial production, and the nanoparticles are satisfied to the application of dental restoration.