添加铋的氧化钆掺氧化铈对电子导电率影响

Effect of Bismuth Addition on the Electrical Conductivity of Gadolinium-doped Ceria Ceramics

利用共沉法制备的Ce0.8(Gd1-xBix)0.2O1.9,对于其结构、热膨胀和离子导电率进行研究。Ce0.8(Gd1-xBix)0.2O1.9在1 350—1 450℃范围内持温6 h进行烧结,Ce0.8(Gd1-xBix)0.2O1.9块材密度皆高于95%理论密度,可发现Ce0.8(Gd0.5Bi0.5)0.2O1.9有最大的离子导电率σ800℃=0.078 S/cm且有最小的活化能Ea=0.638 eV。以共沉法制备添加铋的氧化钆掺杂氧化铈可降低烧结温度。Ce0.8(Gd1-xBix)0.2O1.9的热膨胀系数分布在(20.132—20.478)×10-6/℃之间。致密的Ce0.8(Gd1-xBix)0.2O1.9其破裂韧性在1.28—2.60 MPa.m1/2之间,且破裂韧性的值会随着铋的含量增加而提高。说明藉由添加铋可改善氧化钆掺杂氧化铈的机械性质。

The structure, thermal expansion and electrical conductivity of Ce0.8（Gd1-xBix）0.2O1.9 ceramics was sintered in the range of 1 350-1 450℃ for 6h;the bulk density of Ce0.8 （Gd1-xBix）0.2O1.9 ceramics was over 95% of the theoretical density; the maximum electrical conductivity, σ800℃ - 0. 078 S/cm with minimum activation energy, Ea = 0. 638 eV was found for the Ce0.8 （Gd0. 5Bi0.5 ）0.2O1.9 ceramic. The gadolinium-doped ceria ceramics preparation by coprecipitation can reduce the sintering temperature by addition of bismuth. The thermal expansion coefficient of Ce0.8 （Gd1-xBix）0.2O1.9 covers the range of 20. 132-20.478 × 10^-6/℃. The ceramic has a fracture toughness in the range of 1.28-2.60 MPa.m1/2 for dense Ce0.8 （Gd1-xBix）0.2O1.9 ceramics. The value of fracture toughness increased with Bi content. It indicated that the mechanical properties of gadolinium-doped ceria ceramics could be improved by addition of bismuth.