Study On Manufacture And Microwave-Absorption Properties Of Z/Y Type Hexagonal Barium Ferrites Doped Rare Earth

The sol-gel method is adoped to synthesize the Z and Y type hexaferrite,andtheir structure and microwave absorption properties are measured. The XRDspectrum shows that the temperature of forming Z/Y type hexaferrite phase is veryhigh.The microwave absorption properties of Z and Y type hexaferrite is best that areobtained at 1300℃and 1050℃respectively. The results of experiments indicate thatthe microwave absorption properties of both kinds of hexaferrite change obviously asthe amount of rare earth cerium and lanthanum doped vary, but they have the similartendency.The microwave absorption properties of Z type hexaferrite with rare earth isbest,When the mol ratio of rare earth cerium and lanthanum is 0.3.The highestabsorption value of the Z type sample that is doped cerium is 47.575dB,and it is38.799dB for the sample without doping.The microwave absorption properties of Ztype hexaferrite with lanthanum reach to the highest value,When the mol ratio of rareearth lanthanum is 0.3.The highest absorption value increases from 34.471dB to37.287dB after doping rare earth lanthanum.As compared with non-dopingcondition,the microwave absorption properties is improved slightly, but it is not obviously when the mol ratio of rare earth is 0.2.But when the tool ratio of rare earthdoped is 0.1 and 0.4,the absorption properties deteriorates,and it is worse than beforedoping.Similarly, the microwave absorption properties of Y type hexaferrite with rareearth reach to the highest value,When the mol ratio of rare earth is 0.3.The highestabsorption value of the sample with rare earth cerium is 27.567dB, and it is only15.71 dB before doping.After doping lanthanum of which the mol ratio is 0.3,thehighest absorption value of the sample is 27.567 dB, that is 4 dB higher than thesample without lanthanum.When mol ratio of rare earth is 0.1,0.2,0.4, themicrowave absorption properties of the sample is improved slightly, but it deterioratesat some frequency as compared with non-doping condition.For studing the microwave-absorbing mechanism, imagionary part ofpermeability and dielectric constent of the samples are measured. The results ofexperiments indicate that the imagionary part of dielectric constent has not notablerule as doping different amount of rare earth. But The frequency corresponding to thepeak of imagionary part of permeability is close to the frequency corresponding to thepeak of the absorption.And the changing rule is similar that the peak of imagionarypart of permeability and absorption change with frequency.Therefore,doping rareearth can advance imagionary part of permeability, so the microwave absorptionproperties of the sample is been improved.In conclusion,only doping proper amount of rare earth cerium and lanthanumcan improve microwave absorption property of Z type and Y type hexaferrite,anddoping more or less amount of these is not favorable to improving microwave absorption properties.