耐高温氧化锆-刚玉-莫来石复相陶瓷的制备及其抗热震性

以煤系高岭土、α-Al2O3和部分稳定氧化锆(PSZ, 3;molY2O3)为原料,制备了耐高温氧化锆-刚玉-莫来石复相陶瓷.采用XRD、SEM等测试技术对样品的物相组成及显微结构进行了表征,研究了PSZ添加量(分别为5wt;、10wt;、15wt;、20wt;、25wt;、30wt;)对样品物理性能、高温塑性变形及抗热震性的影响.结果表明:由于采用含3;molY2O3的PSZ,Y2O3在高温下起到了烧结助剂的作用,致使样品的烧成温度显著降低;同时随着PSZ添加量的增加,样品的抗折强度增加.经最佳烧成温度烧成的各样品的抗折强度分别达到147.4 MPa、161.3 MPa、205.9 MPa、234.4 MPa、294.0 MPa、385.0 MPa.当PSZ的最佳添加量为10wt;时,样品具有较低的高温塑性变形及良好的抗热震性;当PSZ添加量继续增加,样品在高温易产生液相,抗蠕变及抗热震性降低.SEM显微结构研究表明,随着氧化锆添加量增加,样品结构越致密,增强效果越显著.XRD分析结果表明,复相陶瓷具有良好的耐高温性能,热震前后样品的物相组成不变,均为莫来石、刚玉、m-ZrO2和t-ZrO2.

Preparation and Thermal Shock Resistance of High-temperature Resistant Zirconia-corundum-mullite Composite Ceramics

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.