(1.Shanghai Institute of Ceramics, Chinese Academy of Sciences, Structural Ceramics Engineering Research Center, Shanghai 200050, China; 2.University of Chinese Academy of Sciences, Beijing 100049, China)
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DOI:
10.7502/j.issn.1674-3962.2015.12.08
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Abstract:
ZrO2 felt/ZrO2 porous composites were fabricated by vacuum – pressure infiltration technique using ZrOCl2?8H2O as precursor. After 12 cycles of infiltration – drying – pyrolysis and sintering at 1450~1600℃, the porous composites with both low thermal conductivity and high mechanical strength were obtained. The effects of sintering temperature on compressive strength and thermal conductivity were investigated on the basis of composition, density, porosity and microstructure. The results showed that a little La2Zr2O7 phase was formed at 1450℃ but disappeared when the sintering temperature increased. As the sintering temperature rose from 1450℃ to 1600℃, the content of c-ZrO2 gradually increased. Meanwhile, the porosity decreased from 50.5% to 45.5% and the compressive strength increased from 16.9 to 40.0 MPa. Possibly, phonon heat conduction dominated heat transfer of the porous composites in the low temperature range. While, convective heat transfer was dominated in the high temperature range. Thermal conductivity of the obtained composites was lower than 0.9 W/(m?k) in the range of 100℃ to 1200℃.