浆料固相含量对数字光处理成形Si3N4陶瓷性能的影响

随着科技的不断发展, Si₃N₄陶瓷在航空、机械、生物医疗等高新领域发挥着越来越重要的作用。本工作采用包覆助烧剂Al₂O₃-Y₂O₃后的Si₃N₄粉体为原材料, 利用数字光处理(Digital light processing, DLP)技术成功制备出Si₃N₄陶瓷, 并系统研究了浆料固相含量对Si₃N₄陶瓷浆料、DLP成形Si₃N₄陶瓷素坯和陶瓷性能的影响。研究表明, 浆料固相含量低于40.0% (体积分数)时, 浆料在30 s^-1剪切速率下的粘度均小于2 Pa·s, 可用于DLP成形。在这种情况下, 浆料的单层固化深度随浆料固相含量的增加而减小。随着浆料固相含量的增大, DLP成形Si₃N₄陶瓷的相对密度和抗弯强度先升高后降低。固相含量为37.5% (体积分数)的样品获得最大的相对密度和抗弯强度, 分别为89.8%和162.5 MPa, 较固相含量为32.5% (体积分数)的样品分别提升了10%和16%。本研究通过对陶瓷浆料性能的优化, 提升了DLP成形Si₃N₄陶瓷的性能, 为Si₃N₄等非氧化物陶瓷光固化成形奠定了实验基础。

Effect of Solid Loading of Slurry on Properties of Si3N4 Ceramics Formed by Digital Light Processing

With the continuous development of science and technology, Si₃N₄ ceramics are playing an increasingly important role in high-tech fields such as aviation machinery, biology and medical treatment. In this work, Si₃N₄ ceramics were successfully prepared by digital light processing (DLP) technology using Si₃N₄ powder coated with Al₂O₃-Y₂O₃ as raw material. Effects of solid loading of slurry on the performance of Si₃N₄ ceramic slurry, Si₃N₄ ceramic green parts and Si₃N₄ ceramics were systematically studied. The results showed that when the solid loading of slurry was less than 40.0% (in volume), its viscosity was less than 2 Pa·s at shear rate of 30 s^-1, which can be used for DLP forming. In that case, the single curing depth of the slurry decreased with the increase of solid loading of the slurry, while the relative density and flexural strength of Si₃N₄ ceramics formed by DLP increased firstly and then decreased. The relative density and flexural strength reached the maximum of 89.8% and 162.5 MPa at solid loading of 37.5% (in volume), which were 10% and 16% higher than those with solid loading of 32.5% (in volume), respectively. In this work, the properties of Si₃N₄ ceramics formed by DLP were optimized by determining the best solid loading, which laid the experimental foundation for the photocuring of non-oxide ceramics such as Si₃N₄.