掺杂SnO_2对NiFe_2O_4陶瓷电导率的影响

Effect of Adding SnO_2 on Electrical Conductivity of Nickel Ferrite Ceramics

采用冷压-烧结粉末冶金技术制备了NiFe2O4陶瓷,并对其进行SnO2掺杂。对光谱纯石墨和所制备的试样进行的不同温度下电导率测试研究表明:用直流四端电极法改进的高温电导率测试仪测定结果重现性和准确性良好;NiFe2O4陶瓷材料的导电性能随着温度升高而提高,且呈现半导体材料特性;掺杂少量SnO2有利于降低材料的活化能,提高其电导率,而不影响陶瓷基体材料的半导体特性。

Nickel ferrite ceramic was prepared with the cold isostatic pressing-sintering process of powder metallurgy and SnO2 was added, an improved high-temperature electrical conductivity test device based on the conventional direct current four-electrode technique was introduced, the electrical conductivities of specimens of spectrum pure grade graphite and ceramics under different temperature were investigated. The results reveal that the reliability and reproducibility of the improved device are excellent; electrical conductivity of NiFe2O4 ceramic will advance with temperature increasing and the material exhibits the property of semiconductor; it is advantageous to decrease the activation energy and improve its electrical conductivity when a little SnO2 is added to NiFe2O4 ceramic, at the same time, the property of its semiconductor will not be affected.