Effect Of Ion Substitution On The Structure And Properties Of M-type Strontium Ferrite

With the rapid development of economy and technology,the global demand for ferrite is growing,as a ferrite production power,the production of high-performance ferrite is a problem has been plagued by the people,the production of high-performance ferrite technology has been Japan's TDK company mastered.Domestic scholars in order to not fall behind,in recent decades has been on the ferrite field and maintained a high enthusiasm for research.In all ferrite materials,M-type ferrite has the advantages of high coercivity,high magnetic energy product,high magnetocrystalline anisotropy,stable performance and low cost.The development of many industries have a very high dependence on M-type ferrite.However,in practical applications,it was found that the actual performance of M-type ferrite and the theoretical value is still a certain gap.In order to improve the magnetic properties of M-type ferrite in the process of improving the process equipment,ion substitution has become the main means to improve the performance of ferrite.In this paper,the lanthanum-zinc-substituted strontium ferrite Sr1-xLaxFe12-yZnyO19 was prepared by the traditional ceramic method,and the value of x/y was 4/3 in the formulation of Sr1-xLaxFe12-yZnyO19.After the effect of La-Zn substitution on the structure and magnetic properties of Sr1-xLaxFe12-yZnyO19 is studied,this thesis studies the effect of Fe3+ ion on the structure and magnetic properties of Sr0.84La0.16FexZn0.12O19.Change the effect of preheating temperature on the performance of the sample.In order to enhance the magnetic properties of M-type strontium ferrite,the addition of SiO2 and Al2O3 was added to the secondary milling,and the optimum additive content was explored by changing the additive content by orthogonal experiment.The effects of co-substitution of magnetic ions Co2+ and La3+on the structure and properties of M-type strontium ferrite under iron-deficient formulation were investigated after the combined substitution of non-magnetic ions Zn3+ and La3+.The results show that Sr11.82La0.18Fe11.70Co0.18O19 has good magnetic properties,and the calcination temperature is changed to explore the effect of temperature on the performance of the sample.The structure,microstructure and magnetic properties of each group were studied by X-ray diffractometer,scanning electron microscope(HITACHI S-4800),vibrating sample magnetometer and BH permanent magnetometer(NIM-2000HF)Measurement and research.The results of the experiment are summarized as follows:1?In the experiment,the lattice constant a value fluctuates greatly with the increase of the doping amount.The value of the lattice constant c decreases monotonically with the increase of the doping amount.When the x=0.16 and y=0.12,the residual magnetization Br reaches a maximum of 395.8 mT,the intrinsic coercivity Hcj is 231.3 kA/m,the magnetic induction coercivity Hcb is 224.7 kA/m,the maximum energy product(B/H)max obtained the maximum value of 29.44 kJ/m3.The optimum formulation for the substitution of lanthanum and zinc for M-type strontium ferrite is Sr0.84La0.16Fe11.88Zn0.12O19.2?In the experiment,the influence of the change of iron content on M-type ferrite was investigated.With the change of Fe3+ ion content,the lattice constant a and c had almost no change.When the iron content is x=11.95,there are miscellaneous peaks.When the content of iron is x=11.65,the better magnetic properties of the M-type strontium ferrite Sr0.84La0.16FexZn0.12O19(11.35?x?11.59)are obtained.The residual magnetization Br is the maximum value of 414.2 mT,the maximum coercivity Hcb is 236.2 kA/m,and the maximum magnetic energy product(BH)max achieves a maximum value of 31.75 kJ/m3.The best formulation of M-type strontium ferrite is Sr0.84La0.16Fe11.65Zn0.12O19.3?A sample was prepared using Sr0.84La0.16Fe11.65Zn0.12O19 as a formulation.Respectively,set 1190,1200,1210,1220,1230? for the calcination temperature,insulation 3h.As the calcination temperature increases,the lattice constants a and c of the sample increase slowly.A miscellaneous peak appears at a temperature of 1230 ?.When presintering temperature is 1210 ?,sample performance is the best,the residual magnetization Br to obtain the maximum 420.6mT,intrinsic coercivity Hcj get the maximum value of 262.1 kA/m,the magnetic induction coercivity Hcb obtains the maximum value of 241.7kA/m,the maximum magnetic energy product(BH)max obtains the maximum value 32.31kJ/m3.4?The samples were prepared by conventional ceramic method using Sr0.84La0.16Fe11.65Zn0.12O19 as the formula.Add the additives SiO2,Al2O3 when the second ball mill.The optimum amount of additive selected by orthogonal experiment was 0.5wt%SiO2?0.5wt%Al2O3.These two additives can reduce the residual magnetization Br of the sample and increase the intrinsic coercivity Hcj.5?In the experiment of lanthanum cobalt substituted M strontium ferrite.With the increase of the substitution amount,the lattice constant a value fluctuates little,and the value of the lattice constant c decreases monotonously with the increase of the doping amount.The residual magnetization Br,intrinsic coercivity Hcj,magnetic coercivity Hcb,The maximum magnetic energy product(B/H)max showed a tendency to increase first and then decrease.In x=0.18,the comprehensive performance of the sample is best,that is the best formulation of lanthanum cobalt substituted M strontium ferrite is Sr0.82La0.18Fe11.70Co0.18O19.6?A sample was prepared using Sr0.82La0.18Fe11.70Co0.18O19 as a formulation.Respectively,set 1190?1205?1220?1235?1250?1265? for the calcination temperature,insulation 3h.With the increase of the calcination temperature,the lattice constants a and c of the samples increase slowly,the residual magnetization Br,the coercivity Hcj,the magnetic induction coercivity Hcb,and the maximum magnetic energy product(BH)max increase the trend after the decrease.When the temperature is 1190 ? and 1265 ?,there are miscellaneous peaks.When the temperature is 1235 ?,the sample performance is better.