关键词: 氧化锆多孔陶瓷, 锆溶胶, 流变性能, 抗热震性

Abstract: The traditional organic foam impregnation process has been hindered by insufficient control over the rheological properties of zirconia slurry and difficulties in zirconia sintering,resulting in insufficient strength and poor thermal shock resistance of zirconia porous ceramics.The zirconia slurry was prepared with yttria-stabilized zirconia powder as the primary raw material,sodium carboxymethyl cellulose as the thickener,zirconia sol as the binder and deionized water as the dispersion medium.Zirconia porous ceramics were fabricated via the organic foam impregnation method by loading the slurry onto polyurethane sponge templates with dimensions of 50 mm×50 mm×25 mm,and heat treating at 1 300,1 400 and 1 500 ℃ for 2 h.The effects of zirconia sol extra-additions (0,5%,10%,and 20%,by mass) on the rheological properties of the zirconia slurry,as well as the zirconia sol extra-additions and the heat treatment temperatures on the microstructure,mechanical properties and thermal shock resistance of the zirconia porous ceramics were investigated.The results indicate that:(1)zirconia sol significantly improves the rheological properties of the zirconia slurry;the slurry with 20% zirconia sol exhibits the optimal rheological performance;(2)zirconia sol coats ZrO₂ particles,fills interparticle gaps,and promotes neck formation; while it also transforms into nano-ZrO₂ during sintering,thus enhancing the sintering of the ceramics;(3)after heat treating at 1 500 ℃,the ZrO₂ porous ceramic with 20% zirconia sol exhibits the optimal overall performance,achieving a strut density of 3.70 g·cm^-3,a room temperature compressive strength of 2.16 MPa,and a residual room temperature compressive strength of 1.87 MPa after thermal cycling.

Key words: zirconia porous ceramics, zirconia sol, rheological properties, thermal shock resistance