氧化铝、硝酸铝复合YSZ的烧结性能、电性能及力学性能研究

Sinterability, Electrical Conductivity and Mechanical Property of YSZ Composite with Alumina or Aluminium Nitrate

摘要:

分别以Al2O3、Al(NO3)3为铝源与氧化钇稳定氧化锆（YSZ）机械混合，经干压技术和高温烧结制得YSZ/Al2O3复合材料。通过扫描电子显微镜、电化学交流阻抗谱和三点弯曲测试等方法对样品进行分析，研究了不同铝源和添加量对YSZ电解质烧结性能、电导率及力学性能的影响。结果表明：适量的Al2O3或Al(NO3)3复合均能够促进YSZ的烧结，提高其电导率和弯曲强度；Al2O3作铝源的复合样品的烧结性能和电导率优于Al(NO3)3铝源的，但其强度低于同比例Al(NO3)3铝源。其中，加入0.5 wt.%Al2O3时，所制备的复合电解质经1350 ℃烧结10 h后的相对密度为98.8%；800 ℃时的电导率达0.0703 S·cm-1。基于该材料制备的电解质支撑型单元电池在800 ℃时以氢气为燃料的最大功率密度为308 mW·cm-2，高于纯YSZ电解质电池的，并表现出良好的稳定性。

Abstract:

Yttria-stabilized zirconia(YSZ)/Al2O3 composite materials were prepared by mechanically mixing, dry pressing and high temperature sintering of YSZ with Al2O3 and Al(NO3)3 as aluminum sources, respectively. The effects of aluminum sources and addition amounts on the sinterability, electrical conductivity and mechanical property of YSZ/Al2O3 composites were investigated by means of scanning electron microscopy, electrochemical impedance spectroscopy and three-point bending test. The results show that addition of suitable amounts of Al2O3 or Al(NO3)3 into YSZ can promote the sinterability of YSZ and improve its electrical conductivity and flexural strength. Sinterability and electrical conductivity of YSZ/Al2O3 composites using Al2O3 as aluminum source are higher than those of using Al(NO3)3, but mechanical strengths exhibit the contrary trend at the same addition amount. When 0.5 wt.% of Al2O3 is added into YSZ, the relative density of 98.8% and the electrical conductivity of 0.0703 S·cm-1 at 800 ℃ are achieved on YSZ/Al2O3 composite electrolyte sintered at 1350 ℃ for 10 h. The electrolyte-supported unit cell constructed by the YSZ/Al2O3 composite electrolyte gives the maximum power density of 308 mW·cm-2 at 800 ℃ using H2 as the fuel, which is higher than that of the pure YSZ electrolyte and exhibits good stability.