简介:Ceriasphereswithdifferentsizesandsulfurizedproductswithcorrespondingmorphologywerepreparedbyhydrothermalandgas-solidreactionmethodat600–800°CunderCS2atmosphereforashorttime,respectively.Dimensionaleffectinpreparationofγ-Ce2S3wasfirstlyinvestigatedbymeansoftechniquessuchasscanningelectronmicroscopy(SEM),X-raydiffraction(XRD),thermalgravimetricanalysis(TGA)andspectrophotometer.Theresultsshowedthatwhenceriananoparticleswithsmallsizewereusedasprecursors,theγ-Ce2S3couldbepreparedatthelowertemperatureandthebadlysinteredproductswereobtained;whenceriananoparticleswithlargesizewereemployedasprecursors,pureγ-Ce2S3wasdifficultlyobtainedevenifthetemperaturewasupto800°Candtheproductstendedtokeeptheiroriginalsize.Theheat-resistancepropertyoftheγ-Ce2S3withlargesizewasbetterthanthesmallerone,andthepureγ-Ce2S3preparedfromprecursorwithsmallsizehadagoodpigmentaryperformance.
简介:AseriesofLa2O3/MCnylonnanocompositeswerepreparedviainsitupolymerization.Theeffectsofcontentofnano-La2O3onthemechanicalpropertiesofnanocompositeswerestudied.Dispersionofnano-La2O3inMCnylonmatrixwasobservedwithSEM.ThecrystalstructureofnanocompositeswascharacterizedbymeansofXRD.SEManalysisshowsthatLa2O3nanoparticlesareuniformlydispersedinMCnylonmatrixandlittleclusteringexistswhenthecontentofnano-La2O3islowerthan1%,however,whenthecontentofnano-La2O3ismorethan1%,itbeginstocluster.XRDanalysisindicatsthatnano-La2O3doesnotchangethecrystalstructureofMCnylon.Mechanicalpropertiestestsshowthatthetensilestrength,elongationatbreak,impactstrength,flexuralstrength,andflexuralmodulusofnanocompositesfirstincreasethendecreaseasthecontentofnano-La2O3isincreased.Whenthecontentofnano-La2O3is0.5%,thetensilestrengthandelongationatbreakofnanocompositesreachmaximum,whichare17.9%and52.1%higherrespectivelythanthoseofMCnylon.Whenthecontentofnano-La2O3is1.0%,theimpactstrength,flexuralstrengthandflexuralmodulusofnanocompositesreachmaximum,whichare36.6%,12.7%and16.3%higherrespectivelythanthoseofMCnylon.
简介:Inthispaper,varioustechniquesincludingBET,XRD,SEMandXPSwereusedtostudythesinteringofpureandLa2O3-dopedtitania.Theexperimentalresultsshowthatsinteringoftitaniaproceedsviavolumediffu-sion.Addingoflanthanumoxidedecreasestherateofsinteringandhindersthephasetransitionfromanatasetorutilecrystalbystrongsurfaceinteractionbetweenthemixedcrystals(La4Ti9O24,La0.66TiO2.99)andTiO2.
简介:Whitebody-color(Y,Gd)BxV1-xO4-x:Eu3+phosphorswerepreparedbycoprecipitationreaction.UnderVUVexcitationat147nm,theredemissioncolorimetricpurityof(Y,Gd)BxV1-xO4-x:Eu3+phosphorismuchbetterthanthatofcommercialPDP(plasmadisplaypanels)phosphor(Y,Gd)BO3:Eu3+.Butitsrelativeemissionintensityisonlyabout90%ofthecommercialphosphor.