造孔剂添加量对凝胶注模成型工艺制备8YSZ多孔陶瓷性能的影响

Effects of Pore-Forming Agent Content on the Properties of Porous 8YSZ Ceramics by TBA Based Gel-Casting

采用叔丁醇基凝胶注模成型工艺结合添加造孔剂法制备了高固相含量的YSZ多孔陶瓷。研究了固相含量为50%(体积分数)时,不同造孔剂添加量对烧结8YSZ多孔陶瓷的孔径及其分布、气孔率、抗弯强度以及热导率的影响。研究结果显示:8YSZ多孔陶瓷的气孔分布均匀,孔径在10μm左右,孔壁致密;气孔率在22.9%～39.8%之间,且随着造孔剂添加量的增加而增加;抗弯强度随着造孔剂添加量的增加而减小,最高可达(85.24±2.31)MPa;热导率在0.735～1.108W/m·K之间,且随着造孔剂添加量的增加而降低。上述结果表明,凝胶注模工艺中同时添加造孔剂不仅可以实现高固相含量多孔陶瓷的制备,而且可以同时实现孔结构可控,最终得到兼具有高强度、高气孔率和低热导率的8YSZ多孔陶瓷。

Porous yttria-stabilized zirconia (YSZ) ceramics were Prepared by tert-butyl alcohol (TBA)-based gel-casting with monodisperse polymethylmethacrylate (PMMA) microspheres (20μm) as both pore-forming agent and lubricant agent. The effects of content of PMMA on the pore size distribution, porosity, flexural strength and thermal conductivity of porous 8YSZ ceramics with TBA-based slurry of 50% (volume fraction) solid loading were investigated. The results show that the pores distribute homogeneously in the matrix with the pore size of 10 μm and denser pore walls, and the porosity increases with increasing of amounts of PMMA in the slurry, the flexural strength decreases from 85.24 MPa to 61.89 MPa and the thermal conductivity changes from 1.108 W/m·K to 0.735 W/m·K when the porosity increases from 22.88% to 39.77%. It is shown that the additions of pore-forming agent during the gelcasting process can not only promote the preparation of porous ceramics with high solid loading, but also can make all the main factors controllable, such as the porosity, the size and shape of pores, the distribution of pores, and the thickness and density of pore walls, and thus the porous ceramics with both high strength and low thermal conductivity can be obtained.