Synthesis And Study Of High Performance M - Type Strontium Ferrite Magnetic Powder

In today’s society development, the permanent magnetic ferrite materials have been widely applied in the field of home appliances, automobile industry, communications, computers, energy conservation and environmental protection products, etc. It play an incomparable role in the future.With the continuous improvement of quality of the life, people also pay more and more attention to the development of permanent magnetic ferrite materials.With the preparation technology and doping elements as the breakthrough point, using the method of ceramic composite, according to the different of wet milling process and the sequence of effective impurity and presintering system, we discussed they effect the performance on the permanent magnetic strontium ferrite under-burnt clinker in advance. At the same time, with a preliminary selected under-burnt clinker, we also studied the secondary additives and the influence of process parameters on the magnetic. The samples are characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), Vibrating Sample Magnetometer (VSM)and the characteristics of permanent magnet automatic measuring instrument.we discussed the mechanism of the permanent magnetic strontium ferrite from the crystal structure,micro structure and the magnetic properties of the magnet.Finally the main results are as follows:(1)Through the different wet milling process experiment, we found that taking2.5h+2.5h wet milling process get the Good value of the Ms,its value was72.09emu/g.(2)First milling SiO2after milling CaCO3, Ms value was71.11emu/g, the Hc value was2278.93Oe.(3)When the heating rate was2.5℃/min, magnetic strontium ferrite under-burnt clinker performance was the best, the Ms value was72.61emu/g.And the Hc value was2334.28Oe。(4)The right amount of lanthanum oxide and alumina oxide could improve permanent magnetic ferrite magnetic,but too much amount would lower the performance.(5)Doping x from0to0.10,Sintered body Sr1-xLaxFei2-xCoxO19(x～0.10), comprehensive performance was best with x=0.04. Accordingly,the Br value was398mT and the HCJ was256KA/m.La-Co Doping did not change the crystal structure of trontium ferrite,it still remained the single magnetopiumbite structure.And the crystal orientation degree of trontium ferrite have been changed obviously.(6)Adding dysprosium oxide can make four indicators of strontium ferrite decreased, It meaned that Dy doping is not conducive to improve the magnetic propertie of strontium ferrite.(7) The process conditions had a great influence on the permanent magnetic strontium ferrite magnetic, especially the influence of sintering temperature.