(中南大学 粉末冶金研究院，长沙 410083)
摘 要: 采用冷冻浇注法，通过调控固相含量和黏结剂浓度，制备孔隙率范围在35.3%~75.0%的多孔氧化锆陶瓷。采用旋转流变仪、扫描电子显微镜(SEM)和万能力学性能测试机表征悬浮液的黏度、多孔氧化锆的微观形貌及抗压强度，研究固相含量和黏结剂浓度的变化对多孔氧化锆孔隙率及抗压强度的影响规律。结果表明，固相含量从10%增加至32%(体积分数)，多孔试样的孔隙率从75.0%降低至35.3%；黏结剂浓度从1%提高至8%(质量分数)，试样的烧结收缩率从25.0%提高至33.4%，孔隙率从75.0%降低至62.7%。抗压测试显示，孔隙率的降低使平均抗压强度由4.5 MPa提升至270.1 MPa，断裂模式从渐进性的屈曲断裂转变为灾难性的脆性断裂。对试样力学性能的分析表明，陶瓷壁之间桥结构的增多利于多孔氧化锆抗压强度的提高。
关键字: 冷冻浇注法；多孔氧化锆；孔隙率；抗压强度
（Powder Metallurgy Research Institute, Central South University, Changsha 410083, China）
Abstract:The porous zirconia prepared by freeze casting with a porosity fraction ranging from 35.3% to 75.0% were prepared by changing the solid loading and binder concentration. The rotational rheometer, scanning electron microscope (SEM) and universal testing machine were used to characterize the viscosity of the suspensions, and the microstructure and compressive strength of porous zirconia. The results show that the solid loading increases from 10% to 32% (volume fraction), the porosity samples decreases from 75.0% to 35.3%. The binder concentration increases from 1% to 8% (mass fraction), the sintering shrinkage of the samples increases from 25.0% to 33.4%, thus decreasing the porosity from 75.0% to 62.7%. The compressive strength test results show that the decrease of porosity increases the average compressive strength from 4.5 MPa to 270.1 MPa and makes the fracture mode change from progressive buckling fracture to catastrophic brittle fracture. The analysis of the compressive strength shows that the increase of the bridge structure between the ceramic walls contributes to the improvement of the compressive strength of porous zirconia.
Key words: freeze casting; porous zirconia; porosity fraction; compressive strength
