CaFe_(0.2)Ti_(0.8)O_(3-δ)混合导体的电导和氧渗透性能研究

STUDY ON ELECTRICAL CONDUCTION AND OXYGEN PERMEATION OF MIXED CONDUCTOR CaFe0.2Ti0.8O3-

采用固相反应法制备了致密的高温混合导体ＣａＦｅ０．２Ｔｉ０．８Ｏ３－δ．测量它在９００～１１００℃的总电导率为０．０８～０．１１Ｓ／ｃｍ，氧渗透率为１０－８～１０－１０ｍｏｌ／ｃｍ２·ｓ．结合总电导与氧渗透的数据计算出样品的电子和离子导电率，在１１００℃时分别为０．１１和８．５×１０－３Ｓ／ｃｍ；氧渗透活化能约为１７０ｋＪ／ｍｏｌ；氧离子和电子电导活化能分别为１７９±６和２２±２ｋＪ／ｍｏｌ．研究表明，通过降低样品的厚度和提高氧离子导电率可进一步改进该体系的氧渗透性能．

Mixed conductor oxide CaFe0.2Ti0.8O3- was characterized by it electrical conductivity and oxygen permeation measurement. The electrical conductivity was in the range of 0.080.11 S/cm at temperature 9001 100 . By exposing one side of disk_shaped samples to a flow of air and the other side to a flow of helium, an oxygen permeation flux as large as 10-810-10 mol/(cm2s) was observed in the same temperature range. The partial conductivities of oxygen ions and electron holes were derived. The apparent activation energy for the transport of oxygen ions(1796 kJ/mol) was found much higher than that for electron hole (222 kJ/mol). It is suggested that the oxygen transport in the oxide can be further promoted by increasing the partial conductivity of oxygen ions and decreasing the thickness of the sample.