Article

Study on sintering process and characteristic of nanosized soft magnetic MnZn ferrite powders

School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China
Rare Metals 01/2006; DOI: 10.1016/S1001-0521(07)60139-9

ABSTRACT The effect of sintering process (especially the sintering temperature) on the magnetic property and microstructure of sintered sample of nanosized soft magnetic MnZn ferrite powder was investigated. The sintered sample of MnZn ferrite was prepared by both traditional pressing and cool isostatic pressing on MnZn ferrite nanoparticals. The sintering process of which was segmented. The density, microstructure and phase composition of sintered sample were analyzed by Archimedes' law, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The grain growth and densification in sintering process of MnZn ferrite were investigated. The magnetic property was measured by vibrating sample magnetometer (VSM) and Nim2000 magnetic material testing system. The results show that the better sintering temperature is 850 °C, at which the better magnetic property and microstructure of sintered compact were obtained.

1 Bookmark
 · 
62 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Wereportonaninvestigationtounravelthedependenceofmagneticpropertiesonmicrostructurewhilethey evolveinparallelundertheinfluenceofsinteringtemperatureofasinglesampleofNi0.5Zn0.5Fe2O4 synthesized viamechanicalalloying.Asinglesample,insteadofthe normallypracticedapproachofusingmultiplesamples, wassinteredatvarioussinteringtemperaturesfrom500 1C to14001C. Themorphologyofthesampleswas studiedbymeansofscanningelectronmicroscopy(SEM)equippedwithEDX;densitymeasurementwas conductedusingtheArchimedesprinciple;andhysteresismeasurementwascarriedoutusinga B–H hysteresisgraphsystem.XRDdatashowedthatthe first appearanceofasinglephasewasat800 1C andan amorphousphasewastracedatlowersinteringtemperatures.Wecorrelatedthemicrostructureandthe magneticpropertiesandshowedthattheimportantgrain-sizethresholdfortheappearanceofsignificant orderedmagnetism(mainlyferromagnetism)wasabout Z0.3 mm.Wefoundthattherewerethreestagesof magneticphaseevolutionproducedviathesinteringprocesswithincreasingtemperatures.The first stagewas dominatedbyparamagneticstateswithsomesuperparamagneticbehavior;thesecondstagewasinfluenced bymoderatelyferromagneticstatesandsomeparamagneticstates;andthethirdstageconsistedofstrongly ferromagneticstateswithnegligibleparamagneticstates.Wefoundthatthreefactorssensitivelyinfluencedthe sample'scontentoforderedmagnetism—theferrite-phasecrystallinitydegree,thenumberofgrainsabovethe criticalgrainsizeandthenumberoflargeenoughgrainsfordomainwallaccommodation.
    Journal of Magnetism and Magnetic Materials 01/2014; 351:16-24. · 1.83 Impact Factor