熔融沉积成型制备致密氮化硅陶瓷

Dense Silicon Nitride Ceramics Prepared by Fused Deposition Modeling

创新地采用基于螺杆挤出和颗粒喂料的熔融沉积模型制备了致密氮化硅陶瓷。研究了喂料的打印性能、脱脂工艺,以及典型的打印缺陷的存在形式。结果表明,氮化硅颗粒喂料具有优异的打印性能,适合打印无支撑的小倾角、薄壁和复杂曲面的部件。本文研究开发的有机黏结剂体系结合溶剂+热两步脱脂工艺在厚截面部件制备中有突出优势,可以实现9 mm厚度的坯体安全脱脂。研究发现FDM的典型工艺缺陷有层间裂隙和路径间孔隙两种。结合气压烧结,制备了抗弯强度(774.5±70)MPa、密度3.25 g/cm^(3)的致密氮化硅陶瓷,并成功制备了形状复杂和维形良好的氮化硅陶瓷零件。

Dense silicon nitride ceramics were prepared innovatively based on the fused deposition modeling(FDM)method with granular feedstock via screw extrusion.The printability of the feedstock,debinding process and typical printing defects were studied.The results show that the feedstock possesses an excellent printing performance and fits for printing unsupported small inclination angles,thin walls and complex curved surfaces.The organic binder system developed in this study combined with a two-step,"solving+heating"dedinding process has outstanding advantages in the preparation of thick-section parts and can achieve safe degreasing of green bodies with a thickness of 9 mm.It was revealed that the typical process defects of FDM include interlayer cracks and interpath pores.Combined with gas pressure sintering,dense silicon nitride ceramics with a bending strength of(774.5±70)MPa and a density of 3.25 g/cm^(3)were prepared,and silicon nitride ceramic parts with complex shapes and good shape keeping were successfully prepared.