Bi_2O_3添加对NFC用NiCuZn铁氧体性能的影响

按组成Ni_(0.28)Cu_(0.27)Zn_(0.45)Fe_(1.91)O_(3.82)制备了NiCuZn铁氧体,在预烧料中添加0.5wt%的Co_2O_3和x的Bi_2O_3(x=0.05,0.1,0.3,0.5,0.7,1.0,1.5,3.0 wt%),在900℃烧结后测试样品微观形貌和磁特性。结果表明,非磁性相Bi_2O_3的引入,一方面导致NiCuZn铁氧体晶粒的生长机制发生变化,从而影响材料磁特性,另外作为非磁性相,其加入量的不同也对磁特性带来不同的影响。少量(x=0.05 wt%~0.3 wt%)Bi_2O_3添加,晶粒平均尺寸为1.4~1.6μm,在获得致密的单畴晶粒结构的同时带来了材料Bs和磁导率μ的提高;当添加量增大时(x=0.5 wt%~3.0wt%),由于非磁性相的增加,磁导率μ与Bs均降低。最佳磁特性m￠值在Bi_2O_3添加为0.1wt%时获得,为196,m2值为3。

Effect of Bi2O3 adding on the properties of NiCuZn ferrite material for NFC application

By adding 0.5wt% Co2O3 and different amount of Bi2O3 (x=0.05, 0.1, 0.3, 0.5, 0.7, 1.0, 1.5, 3.0 wt%) the calcined powders, NiCuZn ferrites with compositions of Ni0.28Cu0.27Zn0.45Fe1.91O3.82 were prepared by conventional ceramic process. Micro morphology and magnetic properties of the test sample after sintering at 900℃were investigated. The results show that the non magnetic phase of Bi2O3 introduced results in changing in the grain growth mechanism of NiCuZn ferrites, thus affecting the magnetic properties. For small amount of Bi2O3(x=0.05 to 0.3 wt%), the sample has an average grain size of 1.4 to 1.6μm, which can increase the density and bring the single domain grains structure and increase the Bs andμ. When the amount of Bi2O3 was increased (x=0.5 to 3.0 wt%), both the Bs andμ decrease with the increase of the addition of the non magnetic phase. The best real part of permeability is obtained for addition amount of Bi2O3 is 0.1wt%, with μ′ = 196,μ″= 3.