铋钙钒柘榴石磁性与微波特性研究

Magnetic and Microwave Properties of Bi-substituted Calcium Vanadium Garnets

以钙钒钇铁柘榴石[(Ca1.2Y1.8)(Fe4.4V0.6)O12,YCVG]为参考组成,尝试以Bi3+部份取代Y3+的方式降低致密化烧结温度,开发具有积层组件应用潜力的低温共烧微波磁性陶瓷.实验结果显示铋的部份取代能有效降低钙钒钇铁柘榴石的烧结温度.当铋取代量为1.0时Bi-CVG的致密化烧结温度可降低至1020℃.Bs与Br值不随成分组成改变而受影响,而Hc与Wh则随铋取代量的增加而增加,当铋取代量大于0.75后Hc与Wh值则急速增加.综合低温烧结特性与磁性表现,(Bi0.75Ca1.2Y1.05)(Fe4.4V0.6)O12是较具实用价值的组成,其烧结条件为1100℃与6h,平均晶粒尺寸为6μm;磁性性质分别为Bs=0.54kG,Br=0.45kG,Hc=2.9Oe,Wh=50J/m3,ΔH=119Gauss.

The effect of Bi-substitution on the magnetic and microwave properties of calcium vanadium garnets(CVG) was studied.The polycrystalline garnet samples with composition of(BiyCa1.2Y1.8-y)(Fe4.4V0.6)O12 were prepared by solid state reaction processes.The amount of Bi-substitution,y,varied from 0 to 1.0.The sintering temperature for densifying the Bi-incorporated CVG materials is significantly decreased as increasing the amount of Bi-species to replace portion of Y constituents.The samples prepared from(Bi1.0Ca1.2Y0.8)(Fe4.4V0.6)O12 can be densified to 98.0% T.D.at 1020℃ for 6 h.Saturated magnetization(Bs) and remaining magnetization(Br) of the Bi-CVG materials almost keep the same values that are not related to the composition of Bi-CVG.Whereas,the coercive field(Hc) of the materials is larger for the samples containing fine grains and vice versa.The strong microstructural dependence of the permeability of Bi-CVG is observed in the microwave regime.