fe3o4@sio2硅油基磁性液体制备及其性能研究

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1、BAILeZHANGZhiliXULongfeiDINannanLIDecaiSchoolofMechanicalandElectronicControlEngineering，BeijingJiaotongUniversity;Abstract：Undernormalcircumstances,theviscosityofsiliconeoilvariesverylittlewithtemperatureandexhibitsexcel1entutemperatureresistance”•Itistheoutstandingadvantageofsiliconeoilasawor

2、kingmediuminaspecialenvironment.Bycombiningthe“temperatureresistance”ofsiliconeoilwithmagneticfluid,theapplicationfieldofmagneticfluidcanbegreatlybroadened.Thecore-shellmagneticparticlesFe3Oj@SiO2werepreparedbychemicalcoprecipitationandhydrolysisofethylorthosilicate.Inthepreparationofmagneticpa

3、rticles,theexperimentalprocesswasmainlydesignedandoptimizedbyorthogonaltestanalysisaccordingtothefactorssuchastheadditionsequenceofreactants，pHofprecursorsolution,coatingtemperatureandtheamountofcoatingagent.ThenthemagneticparticleswerecoatedwithsilanecouplingagentA1120.Thecoatedmagneticparticl

4、esweredispersedinsiliconeoilbythedispersionmethodofultrasonicdispersionandhighenergyballmillingtopreparesiliconeoilbasedmagneticfluid.Byusingvibratingsamplemagnetometer,infraredspectroscopy,X-raydiffraction,transmissionelectronmicroscopyandothertestingmethods,themagneticparticleswerecharacteriz

5、edandthestabilityandrheologicalpropertiesofsiliconoilbasedmagneticfluidwereanalyzed.Theresultsindicatethatcore-shellnano-magneticparticlesaremonodisperseandsuperparamagneticwithaparticlesizeof15-20nm.Thesilica-basedmagneticfluidhasasaturationmagnetizationof2.51X10“Tandshowsexcellentstabilityand

6、viscosity-tcmpcraturcperformance.Keyword：magneticfluid;preparation;siliconeoil;core-shellnano-magneticparticlesFe304@Si02;characterization;Received：2017-04-130引言磁性液体由磁性颗粒、表面活性剂、基载液3部分组成。单个磁性颗粒的粒径一般在5~20nm范围内，粒径过大会使磁性液体产生剩磁与矫顽力，从而失去超顺磁性U1;表面活性剂与基载液种类较多，二者需配合使用。磁性颗粒的分散性是影响磁性液体稳定性的决定性因素，它主要取决于颗粒间的

7、范德华力和静电斥力的相互作用m。磁性液体屮固相颗粒数目巨大，据估算，每毫升磁性液体含有1CT10个磁性颗粒，但在没有磁场存在时磁性液体不会表现出磁性，原因是尺寸处于纳米量级的磁性颗粒无时无刻都在做着Brown运动，这种杂乱无章的热运动使磁性颗粒的磁矩朝向空间各个方向的几率相同，磁矩之间相互抵消，因此总体上无异于非磁性材料m。磁性液体兼具了固体和液体材料的性能，在密封、减振、传感器等各方面具有广泛的应用［4-5］，从其制备到应用涉及到丫诸多学科，引起了物理、