GAO Rongze, FENG Tianyi, FENG Weijia, WU Yin

(School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China)

Abstract: ZnO whisker and ZrO₂ were added into porous 95Al₂O₃ ceramics prepared by using gel-casting process to increase their compressive strength. Porosity of the ceramics added with ZnO whisker and ZrO₂ was studied by using the Archimedes method. Pore size distribution was characterized by using mercury intrusion porosimetry. Compressive strength was measured by using compression test. Microstructure and phase composition were examined by using scanning electron microscopy (SEM) and X-ray diffractometer (XRD). It was found that the addition of ZnO whisker had almost no effect on density and porosity of the 95Al₂O₃ ceramics, but the compressive strength was increased from 11.7 MPa to 18.0 MPa. The presence of ZrO₂ decreased the porosity and increased the compressive strength. The 10 vol.% sample with 20 wt.% ZrO₂ possessed a compressive strength of 20.3 MPa.
Key words: porous ceramics; gel casting; Al₂O₃; porosity; compressive strength