Preparation And Properties Of PPy/BaFe_12-xM_xO₁₉?M=Al?Ce?Gd? Composites

With the rapid development of the electronics industry,various electronic equipment has gradually increased,and the pollution of electromagnetic waves has become more and more serious.Almost everyone's life is inseparable from the use of mobile phones and computers.Electromagnetic waves affect everyone's health to varying degrees.Therefore,effective a.bsorbing materials need to be developed in reducing the interference of electromagnetic waves.In this work,hydrothermal method is mainly used to prepare BaFe_12-xM_xO₁₉?M=Al,Ce,Gd?.The samples were coated with polypyrrole.The effects of different doping ions,doping amounts,and the effect of coating polypyrrole on BaFe_12-xM_xO₁₉ were analyzed by XRD,IR,SEM,VSM,VAN.The results show that BaFe_12-xM_xO₁₉?M=Al,Ce,Gd?and their polypyrrole-coated samples prepared by hydrothermal method have a hexagonal sheet structure.The magnetic and absorbing properties of the sample is affected by doping ions and ratios.Among the samples of BaFe_12-xAl_xO₁₉ series,the saturation magnetization Ms and residual magnetization Mr BaFe₇Al₅O₁₉ are the largest,18.76 emu/g and 7.74 emu/g,respectively,BaFe₉Al₃O₁₉ has the largest Hc value of 862.25 Oe,?value of 0.092mm^-1,dielectric loss is 0.211,and magnetic loss of 0.22.After coating with polypyrrole PPy,the magnetic properties of the sample become smaller and the microwave absorbing performance becomes larger.The maxmum?value of PPy/BaFe₂Al₁₀O₁₉ is1.235 mm^-1,the dielectric loss is of 1.099,and the magnetic loss is of 1.191.The maximum values of Ms and Mr are 19.02 emu/g and 7.43 emu/g.The largest value of Hc 862.25Oe is obtained by BaFe_11.6Ce_0.4O₁₉.After coating,the magnetism becomes smaller and the wave absorbing performance is improved.The?value of PPy/BaFe_11.2Ce_0.8O₁₉ can reach 1.179mm^-1,the dielectric loss is 1.382,and the magnetic loss is 1.090.Among the samples of BaFe_12-xGd_xO₁₉ series,BaFe_11.2Gd_0.8O₁₉ has the largest Ms and Mr,which can reach 32.45emu/g and14.16emu/g.The maximum Hc of BaFe_11.8Gd_0.2O₁₉ is 1043.25Oe;The?value of PPy/BaFe₁₁GdO₁₉ can reach 1.207,and the dielectric loss and magnetic loss are 1.121and 11.126,respectively.It can be seen from the comparison that the Ms and Mr of the barium ferrite doped with Al³⁺and Ce³⁺decrease,but the Ms and Mr of the sample doped with Gd³⁺increase,and the change of Hc is irregularly.The doping of the three ions makes the absorbing performance better.After coating with polypyrrole,the magnetic properties of the sample decreased,but the dielectric loss,magnetic loss and?value were larger than before coating,and the wave absorption effect became better.