摘要
详细研究了混合离子导体SrFe1.5-xCoxOy(x =0 .0～ 0 .5)的相组成和氧化学扩散性质 .X射线衍射和扫描电镜分析表明 :该体系随Co含量的增加由Sr4 Fe6 -xCoxO13+δ层状相逐步变为含钙钛矿等物相的多相区 .采用电导弛豫法测定了样品的氧化学扩散系数 .Sr4 Fe6 -xCoxO13+δ型层状相具有较高的氧化学扩散系数 ,钴含量为0 .0 ,0 .1 5和 0 .2 5时氧扩散活化能分别为 ( 1 4 0± 6) ,( 76± 7)和( 77± 6)kJ·mol- 1.氧化学扩散系数值随Co含量增加而降低 ,这可能是因为Co导致有效氧空位浓度减少所致 .此外还研究了多相区内氧化学扩散系数随温度变化的关系 .
Study of the phase composition and oxygen chemical diffusion properties of SrFe 1.5- x Co x O y ( x =0.0—0.5) is presented in the paper. XRD and SEM analysis reveal that with cobalt content x in the range of 0.0 to 0.25, the system consists mainly of layered Sr 4Fe 6- x Co x O 13- δ phase, and further increasing of x leads to partial decomposition of the layered oxide to perovskite phase. Electrical conductivity relaxation method was used to determine the oxygen chemical diffusion coefficients D ～. It is found that for the layered phase with x = 0.0 ,0.15,0.25, the apparent activation energies are (140±6),(76±7) and (77±6) kJ/mol respectively. The value of D ～ decreases with the increase of cobalt content, which may be attributed to the lower effective oxygen vacancy concentration at higher x value. The temperature dependence of D ～ in the multi_phase region is also discussed.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2000年第1期20-24,共5页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金!资助项目 ( 597892 0 1 )
国家 863新材料委员会资助!项目 ( 71 5-0 0 6-0 1 2 0 )
关键词
混合导体
氧化扩散
相转变
SrFe
氧化钴
mixed oxygen ionic and electronic conductor
oxygen chemical diffusion
phase transition
