Ca^(2+)取代对SrCaLaCo铁氧体的微结构和磁特性的影响

Effect of Ca^(2+) substitution on the microstructure and magnetic properties of Sr-Ca-La-Co type hexaferrites

用普通陶瓷工艺制备了分子式为Sr_(0.62-x)La_(0.38)Ca_xCo_(0.24)Fe_(0.14)^(2+)Fe_(11.62-σ)^(3+)O_(19)(x=0,0.2,0.4,0.6,缺铁量d=1.36)的SrCaLaCo铁氧体,研究了Ca^(2+)取代对材料微结构和磁特性的影响。实验表明,Ca^(2+)不仅进入晶格参与形成M型的六角铁氧体,而且还存在于晶界中影响晶粒的生长。当x=0.4时,预烧样品在1240℃时可形成单一的M相,比饱和磁化强度(σ_s)和矫顽力(H_(cj))达到最大,分别为69.3A×m^2/kg和334k A/m(4329Oe)。当烧结温度为1170℃×1h时,烧结样品获得最佳性能:剩余磁化强度B_r=445m T,矫顽力H_(cj)=420k A/m。

The SrCaLaCo ferrites as formula Sr0.62-xLa0.38CaxCo0.24Fe20.14?Fe311.62???O19(x=0,0.2,0.4,0.6,?=1.36)were prepared using conventional ceramic process.The effect of Ca2+substitution on the microstructure and magnetic properties of the materials was studied.The experiment shows that,Ca2+into the crystal lattice is not only involves in theformation of M-type hexagonal ferrite,but also affect the growth of grains in the presence of grain boundaries.The optimum calcining temperature for single phase of M-type hexagonal ferrite of specimens was1240℃for1h when x=0.4,the largestσs and Hcj were69.3A?m2/kg and334kA/m(4392Oe),respectively.The optimal magnetic properties ofsample sintered at1170℃for1h,the largest Br and Hcj were445mT and420kA/m for x=0.4.