0.8Sr 0.2Ga 1??? x Co x O 3??? δ and its application in a limiting current oxygen sensor]]>

摘要

La~(0.8)Sr~(0.2)Ga~(1??? x )Co~( x )O~(3??? δ )(0.1?≤? x?≤ ?0.9, given the nomenclature LSGC1 to LSGC9, respectively), LSGC, was synthesized by solid state reaction method and its crystalline structure, electrical conductivity, and thermal expansion were characterized, respectively. A limiting current oxygen sensor was prepared with La~(0.8)Sr~(0.2)Ga~(0.8)Mg~(0.2)O~(3??? δ )(LSGM) solid electrolyte and La~(0.8)Sr~(0.2)Ga~(0.1)Co~(0.9)O~(3??? δ )(LSGC9) dense diffusion barrier. Influences of temperature ( T ), oxygen concentration ( x (O~(2))), and thickness of dense diffusion barrier ( L ) on sensing characteristics of the limiting current oxygen sensor were investigated, respectively. The results show that LSGC belongs to perovskite structure and its electrical conductivity increases with increasing Co content x . Oxygen loss of LSGC3, LSGC5, and LSGC7 on the lattice occurs at high temperature and a transition from semiconductive to pseudo-metallic behavior was observed for LSGC3, LSGC5, LSGC7, and LSGC9. Thermal expansion coefficient (TEC) of LSGC increases to a maximum at LSGC7 and then decreases with increasing x in a temperature range of 300–1000?°C. The limiting current oxygen sensor exhibits excellent sensing characteristics. Log I ~(L)depends linearly on 1000/ T , I ~(L)depends linearly on x (O~(2)), and I ~(L)decreases with increasing L .