表面包覆Al_2O_3对3Y-TZP陶瓷烧结致密化及时效敏感性的影响（英文）

Effect of Al_2O_3 Coating on Densification and Aging Sensibility of 3Y-TZP Ceramics

采用非均相沉淀法在3 mol%氧化钇稳定的氧化锆粉体表面包覆0.5%-1.5%（质量分数）的Al2O3,研究了包覆Al2O3对3Y-TZP陶瓷的致密化及时效敏感性的影响。实验采用热膨胀仪测定氧化锆生坯的致密化过程,生坯经1450℃烧结致密化后,测试烧结体的密度、平均晶粒直径和机械性能。采用XRD、SEM表征材料的显微组织。结果表明：相比于传统的共沉淀法,通过表面包覆的方式向氧化锆中加入少量的Al2O3更能促进3Y-TZP陶瓷的烧结致密化。表面包覆少量Al2O3的3Y-TZP可在1350-1400℃烧结致密化。此外,表面包覆Al2O3能显著降低3Y-TZP陶瓷的时效敏感性,这与大量Al3＋在3Y-TZP陶瓷晶界的偏聚有关。

A12O3 dopants in amount up to 1,5 wt% were coated on 3-mol-yttria-stabilized zirconia nanopowders adopting heterogeneous precipitation method. The influences of A1203 coating on the densification and the aging sensibility of 3Y-TZP were investigated. The process of densification was measured using a dilatometer. The density, the mean grain size and the mechanical properties of the densified 3Y-TZP were tested. X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used to characterize the microstructures of specimens. The results show that the densification of A1203-coated zirconia compacts was greatly enhanced by the coating process compared with the conventional co-precipitation process. Dense 3Y-TZP （〉6.0 g/cm3） can be obtained using the A1203-coated starting powders by pressureless sintering at 1350-1400 ℃. In addition, the aging sensibility of 3Y-TZP is substantially decreased by adding A12O3. This is probably attributed to the segregation of A13＋ at the grain boundaries of A12O3-coated 3Y-TZP.