Effect Of Ion Substitution On The Structure And Properties Of M Type Ferrites

Ferrite materials have been widely used since its inception.Among them,strontium ferrite has been intensively studied as a magnetic recording medium as an M-type hexagonal ferrite having a high coercivity and a small particle diameter.Especially the strontium ferrite with semiconductor type,which is used in the air gap magnetic circuit because of its small eddy current loss,high resistivity and large coercive force,is especially suitable for various types of motors.Because of its raw material is iron and strontium oxide is not a precious metal oxide and has a rich source of raw materials,low cost simple process features,can replace the AlNiCo series ferrite.In this thesis,M-type strontium ferrite is prepared by the traditional industrial methods.Various test instruments are used to explore the effect of different numbers and types of ion substitution on the structure and properties of the sample.The specific contents include the following aspects:M type hexagonal ferrite magnetic powder was successfully prepared by the traditional industrial method.The relative properties of samples in which lanthanum ions replaced strontium ions were investigated.According to the results of phase analysis,the samples with La substitution of 0?0.3 were pure magnetoplumbite phases,and ?-Fe2O3 phase began to appear when the content of La was 0.4 and 0.5.The results of the fitting and the spectrum show that the difference curve is relatively flat and the values of the parameters are sufficient to show that the sample is better and the purity is higher.SEM studies show that with the increase of x,the morphology of the ferrite particles does not change,the ferrite has a hexagonal structure and the grain size distribution is uniform.For coercivity,La increases first and then decreases when La substitution increases from 0 to 0.5.The results of the vibrating sample magnetometer show that Ms increases with the increase of La substitution from 0 to 0.1.When La substitution is from 0.1 to 0.5,Ms decreases first and then increases.This shows that the substitution of La does have an impact on performance.M type hexagonal ferrite magnetic powder was successfully prepared by the traditional industrial method.The relative properties of both the lanthanum and the cobalt ions replacing the strontium and iron ions samples were investigated.According to the results of phase analysis,the sample with La-Co substitution amount of 0.3-0.6 is a pure magnetoplumbite phase.However,the a-Fe2O3 phase starts to appear when the substitution amount of La-Co is 0.1 and 0.2.This may be due to the preparation process in the error caused by.The results of the fitting and the spectrum show that the difference curve is relatively flat,and the values of the parameters are sufficient to show that the sample is better and the purity is higher.SEM studies show that with the increase of x,the morphology of the ferrite particles does not change,the ferrite has a hexagonal structure and the grain size distribution is uniform.The results of the vibrating sample magnetometer show that Ms decreases with increasing the La-Co substitution amount from 0 to 0.4.The saturation magnetization(Ms)increases with La-Co substitution from 0.4 to 0.6.For coercivity,the coercivity(Hc)firstly increases and then decreaZses when the La-Co substitution amount increases from 0 to 0.6.This shows that the substitution of La-Co does have a great influence on the magnetic properties,and the average of the two magnetic properties of magnetic properties has been improved at the same time compared with the first experiment.Built on the above two experiments,we tried four yuan substitution.We are still using the solid-phase ball milling successfully prepared M-type hexagonal ferrite magnetic powder.We fixed the three elements of La-Co-Ti unchanged,only change the Ca content.The relevant properties of calcium ion-substituted strontium ions were investigated.According to the results of XRD,there is only a single magnetoplumbite phase in the sample with Ca substitution of 0?0.04,however,the ?-Fe2O3 phase starts to appear when the substitution amount of Ca is 0.05.This may be caused by errors in the preparation process of.The results of the fitting and the spectrum show that the difference curve is relatively flat,and the values of the parameters are sufficient to show that the sample is better and the purity is higher.SEM studies show that,with the increase of x,the morphology of the ferrite particles does not change,the ferrite forms a hexagonal structure.The results of the vibrating sample magnetometer show that Ms decreases with increasing Ca substitution(x)from 0 to 0.01,while increasing saturation magnetization(Ms)with the Ca substitution from 0.01 to 0.02.When the substitution amount increases from 0.02 to 0.05,Ms first increased and then decreased.For the coercivity,when the Ca substitution amount increases from 0 to 0.04,Hc increases first and then decreases;from 0.04 to 0.05,it increases again.