【摘要】 本文借助穆斯堡尔谱学研究了大气烧成条件下Sr(Fe_1-xTi_x)O_3-δ系陶瓷材料的电导和电导温度特性,揭示了电导与氧缺位、Fe⁴⁺含量的关系。研究发现,SrFeO_3-δ系陶瓷中存在过去未知的Fe_（π）³⁺。更多还原

【Abstract】 The conductivity and conductivity-temperature characteristics at room temperature and 78K of ceramics series Sr(Fe1-xTix)O3.δ fired in air are studied by means of the Moessbauer spectroscopy. After a quantitative analysis of Fe4+ content in the solid solution, the concentrations of oxygen vacancy are calculated and the relationship between Fe4+ content and conductivity is found. It is also found that at x = 0. 7 on the curve the turning points of conductivity and material constant B as well as Fe4+ and the percentage of oxygen vacancy occur. When x≥0. 7, Fe(II)8+ which has never been reported before disappears and the lattice parameters no longer vary with x. Besides Fe4+, Fe(II)8+ can also be a factor affecting the conductivity. In contrast to SrFeO3-δ, a series with high conductivity, in which the content of Fe4+ increases with a decrease of δ, the solid solution discussed has a low conductivity, which decreases with a decrease of its δ value because of the introduction of Ti4+ which leads to lower concentration of Fe4+.This is a promising kind of ceramics for NTC thermistors, whose properties are stable and the conductivity and material constant B can easily be controlled.更多还原