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

摘要： 传统的有机泡沫浸渍工艺因存在氧化锆浆料流变性能调控不足和氧化锆烧结困难等问题,导致氧化锆多孔陶瓷的强度和抗热震性能不佳。以氧化钇稳定氧化锆粉末为主要原料,羧甲基纤维素钠为增稠剂,锆溶胶为结合剂,去离子水为分散介质,制备了氧化锆浆料,并通过有机泡沫浸渍法将浆料负载于50 mm×50 mm×25 mm的聚氨酯海绵模板,经1 300、1 400、1 500 ℃保温2 h热处理,制备氧化锆多孔陶瓷。研究了锆溶胶加入量(外加质量分数分别为0、5%、10%和20%)对氧化锆浆料流变性能的影响,同时研究了锆溶胶加入量和热处理温度对氧化锆多孔陶瓷显微结构、力学性能和抗热震性能的影响。结果表明:1)锆溶胶能显著提高氧化锆浆料的流变性,添加20%(w)锆溶胶的浆料流变性表现最优;2)锆溶胶能包裹氧化锆颗粒并填充颗粒间隙,促进颗粒间的颈部连接,同时在烧结过程中转变为纳米氧化锆,促进氧化锆多孔陶瓷的烧结;3)经1 500 ℃热处理后,添加20%(w)锆溶胶的氧化锆多孔陶瓷综合性能最优,其孔筋体积密度为3.70 g·cm^-3,室温压缩强度为2.16 MPa,热震循环后的室温压缩强度为1.87 MPa。

关键词: 氧化锆多孔陶瓷, 锆溶胶, 流变性能, 抗热震性