Research Of Lanthanum Cobalt Substituted M-type Permanent Magnetic Ferrites

Since the M type permanent ferrite MFe12O19(M=Ba, Sr, Pb) was found in the1950s, it has been widely used in various fields due toits advantages such as low-cost,large output andhardly oxidized. In spite of their relatively modest magnetic properties,the ferrite magnets still show the best performance to cost ratio. For that reason, anddespite the recent development of the rare earth based magnets, hard ferrites still remainthe first permanent magnet material both in tonnage and in value.To fulfill the marketrequirements, ferrite magnets with improved magnetic properties have always beendeveloped.The latest breakthrough is based on partial substitutionswith rare earth elements,preferably lanthanum, and withtransition metals, preferably cobalt, using aSr1-xLaxFe2n-yCoyO19modified chemical formula.This paper studies the M-type lanthanum cobalt substitutedpermanent ferriteSr1-xLaxFe2n-yCoyO19, which wasprepared by the traditional ceramic process. The influenceof lanthanum-cobaltsubstitution, calcium-silicon doping and other factors onthemicrostructure and magnetic properties of M type permanent ferrite Sr1-xLaxFe2n-yCoyO19was carefully investigated. Lanthanum cobalt substituted M type permanent magneticstrontium ferrite Sr1-xLaxFe2n-yCoyO19was investigated bydesign of experiment methods,mainly because of the DOE method is easy to program and analysis, especially indetermining the key factors from many related factors, and tell the interactions betweenthe factors.First of all, in this paper, doping amount of lanthanum cobalt before pre-sintered,pre-sintering temperature and secondary lanthanum cobalt doping amount, sinteringtemperature were analysed as the research object. By means of Pareto diagram the keyfactors and the interaction between factors are investagated. Then the doping amount oflanthanum, cobalt, silicon, calcium were analysed to mainly research aboutthe influence of SiCa oxide and its combination on microstructure and magnetic properties when thedoping amount of LaCo changes. XRD, SEM and VSM were used to analysischaracterization of crystal structure, morphology and magnetic properties of pre-sinteredmaterials. The joint action of calcium silicon lanthanum cobalt on M type permanentmagnet ferrite magnetic was carefully investigated. At last, we designed the Z80seriesexperiments, prepared high-performance lanthanum cobalt substituted M-type permanentferrites.