简介:Anewroutetosynthesizenanosizedcrystallineof(La0.67–XGdX)Sr0.33MnO3(X=0.05,0.10,0.15,0.20)perovskite-typecomplexoxidesatcalcinationtemperatureof600-1000°Cusingtheamorphousmolecularalloyasprecursorswasreported.Theprecursorcouldbecompletelydecomposedintocomplexoxideattemperaturebelow500°CaccordingtotheTGAandDTAresults.XRDdemonstratesthatthedecomposedspeciesiscomposedofperovskite-typestructureatcalcinationtemperatureof600°Cfor2h.Theparticlesizethatdependsonthecalcinationtemperatureoftheprecursorisinarangeof30-120nmasdeterminedbytransmissionelectronmicroscopy(TEM).Thismethodiseffectiveandcanbeeasilyquantitativelycontrolledtosynthesizenanosizedperovskite-typecomplexoxides.Themagneticpropertiesof(La0.67–XGdX)Sr0.33MnO3nanocrystallinewerepreliminarystudied.
简介:钛酸锶钡(BST)陶瓷是一种性能优异的电容器材料、热敏材料和铁电压电材料,具有非常广阔的应用领域。采用溶胶-凝胶法合成了Ba0.6Sr0.4TiO3纳米粉体,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、激光粒度分析仪对粉体的物相组成、颗粒大小和形态进行了分析,利用红外光谱仪(FT~IR)研究了表面活性剂在合成纳米Ba0.6Sr0.4TiO3过程中的作用,并重点考察了表面活性剂对Ba0.6Sr0.4TiO3粉体性能的影响。研究结果表明,通过添加适量的表面活性剂能有效改善纳米钛酸锶钡粉体的表面性能,使纳米钛酸锶钡具有较好的分散性,可充分发挥材料的纳米效应。
简介:Anitrate-citratecombustionroutetosynthesizeLa0.9Sr0.1Ga0.8Mg0.2O3-δpowderforsolidoxidefuelcellapplicationwaspresented.Thisrouteisbasedonthegellingofnitratesolutionsbytheadditionofcitricacidandammoniumhydroxide,followedbyanintensecombustionprocessduetoanexothermicredoxreactionbetweennitrateandcitrateions.TheoptimumtechnicalparametersarethatthepHvalueis5,andthemolarratioofcitricacidtothetotalmetallicionis1.5:1.X-raydiffractioncharacterizationofcalcinedgelshowsthatpurephasewassynthesizedaftercalcinationat1400℃for10h,andtheTEMresultshowsthecalcinedpowderwithaverageparticlesizeisabout150nm.Thegrainresistancecontributestothetotalresistanceofsinteredpelletbelow500℃.Theconductivityofthesinteredpellentat800℃was0.07S-1.cm-1higherthantheconductivityofYSZ(0.05S-1.cm-1at800℃)
简介:ThetransportpropertiesintheLa2/3(Ca1-xSrx)1/3MnO3(x=0,1/3,2/3)filmspreparedusingtheRFmagnetronsputteringmethodwereinvestigated.TheeffectoftheCa,Srdouble-dopingattheApositionintheLa2/3A1/3MnO3onthestructureofthetargetsandtransportofthefilmshasbeenstudied.Withtheincreaseofx,thestructuresofthetargetstransformfromtherhombohedralphasetothecubicphase;themetal-insulatorphasetransitiontemperature(Tp)ofthefilmsincreases;andthecorrespondingpeakresistivitydecreases.Allthephenomenacanbequalitativelyexplainedbythelatticeeffect.