Ca~(2+)取代对SrCaLaCo铁氧体的微结构和磁特性的影响

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。

Effect of Ca2+ substitution on the microstructure and magnetic properties of Sr-Ca-La-Co type hexaferrites

The SrCaLaCo ferrites as formula Sr0.62-xLa0.38CaxCo0.24Fe2+0.14 Fe3+11.62-δ O19 (x=0,0.2,0.4,0.6,δ=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 the formation 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 was 1240 ℃ for 1 h when x=0.4,the largest σrs and Hcj were 69.3 A·m2/kg and 334kA/m(4392Oe),respectively.The optimal magnetic properties of sample sintered at 1170 ℃ for lh,the largest Br and Hcj were 445mT and 420kA/m for x=0.4.