掺杂对高磁导率MnZn铁氧体磁特性的影响

研究了CaCO3和Bi2O3掺杂及烧结气氛对高磁导率MnZn铁氧体磁特性及微观结构的影响．研究结果表明，由于CaCO3存在于晶界，合适的CaCO3掺入量会使晶界明显，晶粒均匀，起始磁导率增加．同时由于Ca^2 与Si^4 共同形成高电阻的晶界层，能够改善材料的起始磁导率的频率特性．由于Bi2O3在烧结过程中分布在晶界，掺入Bi2O3促进了晶粒生长．为了减小烧结样品内部和外部氧含量的差别，必须通过控制烧结气氛，保证Zn^2 尽可能少挥发，同时防止Fe和Mn离子变价，从而避免起始磁导率下降．

Effect of addition on magnetic properties and microstructure of MnZn ferrites with high permeability

The effect of additive CaCO 3, Bi 2O 3 and controlling oxygen content of sintered MnZn ferrite on magnetic properties and microstructure was investigated in order to achieve high initial permeability MnZn ferrite. The results showed that proper additive CaCO 3 exiting on the grain boundaries could facilitate the distinction of grain boundaries and uniformity of the grain,to enhance initial permeability. Grain boundary layer of high resistance formed by Ca 2+ and Si 4+ could promote initial permeability frequency characteristics. Additive Bi 2O 3 exiting on the grain boundaries could promote grain growth. The oxygen content of sintered high permeability ferrite must be controlled to ensure less evaporation of Zn 2+ and stop valence change of Fe and Mn for reducing the difference in oxygen content between the interior and exterior of sintered samples.