预烧和烧结温度对SrCaLaCo铁氧体的微结构及磁特性的影响

采用传统的陶瓷工艺制备了分子式为Sr_(0.22)La_(0.38)Ca_(0.4)Fe_(0.14)~(2+)Fe_(11.62-δ)~(3+)Co_(0.24)O_(19)(缺铁量δ=1.36)的M型铁氧体,研究了预烧和烧结工艺对其微结构及磁特性的影响。研究表明,当预烧温度为1160℃和烧结温度为1170℃时,样品的B_r具有最大值455mT,此时对应H_(cj)=400kA/m,(BH)_(max)=40kJ/m~3;获得单一M相的最佳预烧温度为1240℃,这时预烧料有最大的σ_s和H_c分别是69.3 A×m~2/kg和334kA/m(4392Oe),烧结样品的H_(cj)能获得最高值为445kA/m,此时对应B_r=446mT,(BH)_(max)=38.5kJ/m~3。说明,在合适的配方及粉末细化工艺条件下才能获得最佳的B_r和H_(cj).

Effect of calcining and sintering temperature on the microstructure and magnetic properties of SrCaLaCo type hexaferrites

We were using the traditional ceramic technology prepared M-type ferrites as the formula Sr0.22La0.38Ca0.4Fe20.14+Fe311.62δ+-Co0.24O19(δ=1.36) and study the effect of sintering process on microstructure and magnetic properties of the ferrites. When the calcining and sintering temperature was 1160℃ and 1170℃,Br has a maximum value 455mT, andHcj=400kA/m, (BH)max =40kJ/m3. The optimum calcining temperature for single phase of M –type hexagonal ferrite of specimens was 1240℃, the largestσs andHcj were 69.3 emu/g and 4392Oe, respectively. TheHcj of the sintered samples reaches a maximum of 445kA/m, andBr=446mT, (BH)max =38.5kJ/m3. Studies have shown that the intrinsic properties of the material and process conditions together determine the properties of the material, under appropriate formula and the powder refining process to get the best Br and Hcj.