预烧对锰锌铁氧体预烧相及烧结显微结构的影响

Influence of Pre-sintering on the Pre-sintered Phase and Microstructure of Sintered Phase of Mn-Zn Ferrite

采用传统的陶瓷工艺制备了Mn-Zn铁氧体。用X射线衍射(XRD)仪和扫描电子显微镜(SEM)研究了预烧温度对铁氧体预烧相及烧结显微结构的影响。结果表明,在840～1000℃预烧相以α-Fe2O3为主。随着预烧温度的升高,α-Fe2O3的含量逐渐增加,而ZnFe2O4和Mn2O3的含量逐渐减少,Mn3O4固溶于ZnFe2O4形成铁锰锌固溶体,且其含量随着预烧温度的升高呈增大趋势。预烧温度对Mn-Zn铁氧体烧结显微结构和功率损耗有较大的影响。适宜的预烧温度可以获得分布均匀、细小的晶粒及低的功耗,低于或高于此预烧温度,都将造成烧结Mn-Zn铁氧体显微结构的恶化和功率损耗的升高。实验结果表明,对于1340℃的烧结温度,最佳预烧温度为960℃。

Mn-Zn ferrites were prepared by oxide ceramic technology. X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used to investigate the influence of pre-sintering temperature on the pre-sintered phases ＇and microstructure of sintered Mn-Zn ferfite. The main phase is α-Fe2O3 in Mn-Zn ferrite at pre-sintering temperatures of 840℃ to 1000℃. With the increase of pre-sintering temperature, the proportion of α-Fe2O3 increases and those of ZnFe2O4 and Mn2O3 decrease gradually. Mn3O4 dissoloves in ZnFe2O4 to form Mn-Fe-Zn solid solution. The higher pre-sintering temperature is in favor of forming more Mn-Fe-Zn solid solution. At the same time, the microstructure and power loss of Mn-Zn ferrites are affected observably by the pre-sintering temperature. Good microstructure and low power loss can be obtained at the suitable pre-sintering temperature of 960℃, and bellow or exceeding this temperature, the microstructure becomes worse and the power loss increases.