Abstract: The high-temperature resistant zirconia-corundum-mullite composite ceramics were prepared from coal series kaolin, α-Al2O3 and partially stabilized zirconia (PSZ, 3;molY2O3).The phase composition and microstructure were determined by the XRD and SEM.The physical properties, pyroplastic deformation and thermal shock resistance were studied as the function of zirconia content (5wt;, 10wt;, 15wt;, 20wt;, 25wt; and 30wt;).The results reveal that the Y2O3, which introduced by PSZ, played as the role of sintering aids at high temperature and lowered the sintering temperature.The bending strength improve significantly as the increase of PSZ content and the bending strength of samples are 147.4 MPa, 161.3 MPa, 205.9 MPa, 234.4 MPa, 294.0 MPa and 385.0 MPa, respectively.The pyroplastic deformation and thermal shock test experiments show that the optimum addition of zirconia is 10wt;, and the pyroplastic deformation and thermal shock resistance would decrease while the content of zirconia increase further.SEM analysis show that with the increasing of zirconia content much denser samples could be obtained and the toughening effects are more obvious.XRD analysis shows that the composite ceramics have good high temperature resistance, for the phase composition of the samples before and after thermal shock is almost the same, namely corundum, mullite, m-ZrO2 and t-ZrO2.

Key words: The high-temperature resistant zirconia-corundum-mullite composite ceramics were prepared from coal series kaolin, α-Al2O3 and partially stabilized zirconia (PSZ, 3;molY2O3).The phase composition and microstructure were determined by the XRD and SEM.The physical properties, pyroplastic deformation and thermal shock resistance were studied as the function of zirconia content (5wt;, 10wt;, 15wt;, 20wt;, 25wt; and 30wt;).The results reveal that the Y2O3, which introduced by PSZ, played as the role of sintering aids at high temperature and lowered the sintering temperature.The bending strength improve significantly as the increase of PSZ content and the bending strength of samples are 147.4 MPa, 161.3 MPa, 205.9 MPa, 234.4 MPa, 294.0 MPa and 385.0 MPa, respectively.The pyroplastic deformation and thermal shock test experiments show that the optimum addition of zirconia is 10wt;, and the pyroplastic deformation and thermal shock resistance would decrease while the content of zirconia increase further.SEM analysis show that with the increasing of zirconia content much denser samples could be obtained and the toughening effects are more obvious.XRD analysis shows that the composite ceramics have good high temperature resistance, for the phase composition of the samples before and after thermal shock is almost the same, namely corundum, mullite, m-ZrO2 and t-ZrO2.