CAO Chunxin ^1,2, SUN Shengrui ², LIU Yangqiao ², CHEN Aiying ¹, FAN Wugang ²
(1. University of Shanghai Science and Technology, Shanghai 200093, China; 2. Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China)

Abstract: In this work, cordierite ceramics were prepared by using high-temperature solid-state reaction method, while fly ash, talc, alumina and magnesium oxide were used as raw materials and erbium oxide (Er₂O₃) was employed as dopant with mass contents of 0, 0.5% and 1.0%. The effects of erbium oxide on phase composition, microstructure and physical properties of the cordierite ceramics were studied. Firstly, the doping of Er₂O₃ promoted the phase formation of cordierite. The optimal doping content is 0.5 wt.% Er₂O₃. The conversion efficiency of cordierite was increased by forming a liquid phase at low temperatures, thus leading increase in the migration rates of Mg²⁺ and Al³⁺.  Secondly, with 0.5 wt.% Er₂O₃, after sintering at 1300 ℃, the specimens had single phases, complete crystallization, suitable grain orientation and absence of abnormal grain growth. Lastly, the optimized sample had bulk density of 2.095 g·cm⁻³, with the apparent porosity and water absorption rate to be 14.86% and 7.09%, respectively. Meanwhile, the compressive strength was 149 MPa, which was 230% higher than that of the undoped specimen. It is confirmed that Er₂O₃ is a promising sintering aid to significantly improve the comprehensive performance of cordierite ceramics.
Key words: cordierite; fly ash; compressive strength; Er₂O₃