氧化钇掺杂四方氧化锆电性能的研究

STUDY ON THE ELECTRICAL PROPERTIES OF YTTRIA-DOPED TETRAGONAL ZIRCONIA

研究了添加 1%Al2 O3(摩尔分数 )和前驱体“清除”晶界杂质两种改善晶界导电性能的方法 ,对四方氧化锆 ( 3%Y2 O3_dopedtetragonalzirconia ,3YTZ)陶瓷烧结体的导电性能的影响。运用XRD ,SEM分析了它们的相组成及其微观结构。在 2 0 0～ 75 0℃下进行交流阻抗谱测试 ,结果表明 :2种方法均对晶界导电性能有明显改善。Al2 O3自ZrO2 晶界进入晶粒 ,参与替代锆原子 ,与氧离子空位形成缔合物 ,降低了氧离子空位浓度 ,引起晶粒电阻有所增大 ,但前驱体“清除”对晶粒电阻没有影响。有效氧离子空位浓度的变化 ,引起了 15 5 0℃烧成的 3YTZ +1%Al2 O3和

The influences caused by the addition of 1% (in mole) Al2O3 and the precursor scavenging method on the electrical properties of 3% (in mole) Y2O3-doped tetragonal zirconia (3YTZ) were studied. The phase composition and the microstructure were examined by XRD and SEM. AC impedance spectroscopy was measured at a temperature range of 200-750°C. The results indicate that the grain boundary conductivity of 3YTZ is much improved by the two methods. However, aluminum ions enter the lattice of zirconia from the grain boundary and the complex between aluminum ions and oxygen vacancies is formed, which results in the increase of grain resistance and the lower concentration of oxygen vacancies due to the formation of the complex between aluminum ions and oxygen vacancies. The change of effective oxygen vacancy concentration, which is due to the formation of the complexes between defects and oxygen ion vacancies, resulting in the difference between activation energies associated with grain boundary conductivity at lower and higher temperature zones for 3YTZ+1%Al2O3 ceramics and 3YTZ ceramics sintered at 1550°C for 4 h.