Effect of residual compressive stress on thermal shock resistance and microstructure of Al2O3–ZrO2 reticulated porous ceramics

Abstract

Al2O3–ZrO2 reticulated porous ceramics (RPCs) with multi-layered struts were produced via polymer replica method, followed by vacuum infiltration process of infiltration slurries with different alumina contents. The rheological behavior of Al2O3–ZrO2 matrix slurries was investigated. Furthermore, the effect of different infiltration slurries on multi-layered structure and thermal shock resistance of Al2O3–ZrO2 RPCs were studied in detail via finite element method. The results revealed that the as-prepared Al2O3–ZrO2 matrix slurries with 0.9 wt% polycarboxylate (FS20) and 0.4 wt% sodium carboxymethyl cellulose (CMC) showed excellent rheological behavior. In addition, the residual stress was formed within multi-layered struts by reason of that the thermal expansion mismatch between the matrix and outer layer. And with increasing of residual compressive stress in the outer layer of ceramics struts, the thermal shock resistance and microstructure of Al2O3–ZrO2 RPCs were meliorated and then gradually deteriorated. The optimal microstructure and the maximum residual strength ratio (88.68%) were obtained when the Al2O3–ZrO2 RPCs were prepared from the infiltration slurries of 85 wt% alumina contents.