简介:ThethermodynamicphasestabilityareadiagramsofBCl3-NH3-SiCl4-H2-ArsystemwereplottedviaFactsagesoftwaretopredictthekineticexperimentalresults.Theeffectsofparameters(ie,partialpressureofreactants,depositiontemperatureandtotalpressure)onthedistributionregionsofsolidphaseproductswereanalyzedbasedonthediagrams.Theresultsshowthat:(a)Solidphaseproductsaremainlyaffectedbydepositiontemperature.TheareaofBN+Si3N4phaseincreaseswiththetemperaturerisingfrom650to900℃,anddecreaseswiththetemperaturerisingfrom900to1200℃;(b)Whentemperatureandtotalpressureareconstants,BN+Si3N4phaseexistsatahighpartialpressureofNH3;(c)Theeffectoftotalsystempressureiscorrelatedtodepositiontemperature.Thetemperaturerangingfrom700to900℃underlowtotalpressureistheoptimumconditionforthedeposition.(d)Appropriatekineticparameterscanbedeterminedbasedontheresultsofthermodynamiccalculation.Si–B–Ncoatingisobtainedvialowpressurechemicalvapordeposition.TheanalysisbyX-rayphotoelectronspectroscopyindicatesthatB–NandSi–Narethemainchemicalbondsofthecoating.
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简介:Layeredcathodematerialsofhigh-temperaturelithiumbatteries,LiNi1/3Mn1/3Co1/3O2aresynthesizedbyasol-gelmethodwithvariationinfinalsinteringtemperatureforboreholeapplications.Thestructure,morphologyandhigh-temperaturedischargeperformanceoftheseresultingproductsareinvestigatedbyX-RayDiffraction(XRD),scanningelectronmicroscopy(SEM),laserparticlesizeanalysis,galvanostaticandpulsedischarge.Theresultsofstructuralanalysisindicatethatthesamplesinteredat800℃hasthecharacteristicsofgoodcrystallinity,narrowsizedistributionandlargespecificsurfaceareaatthesametime.Thedischargeexperimentsalsoindicatethatthissamplehasthebestelectrochemicalproperties,withthemaximumdischargecapacitiesof314.57and434.14mAh·g-1at200and300℃respectivelyandtheminimumcellinternalresistancesatbothtemperatures.
简介:Defectsofpolymer-derivedSi-C-OfiberswereintensivelystudiedbytheSEMandTEMtechniquesandtheiroriginationswerealsodiscussedonthebasisoffactorsexperiments.Thedefectswerefoundmainlyintheformofstrumaes,pitsandsplitsonsurfacesaswellasmicroflawnetworks,porosityclustersandinclusionsinthebulk.Factorsexperimentsrevealthatanonuniformoraninsufficientcuringwouldresultinlarger-sizedstru-maesorinteriormicroflaws.Gasevolutionratesduetodifferentfiringrateshaveagreatinfluenceontheformationofinternalmicrofiawsorporosityclustersandsomeoxidation-inducedpitsorsplitsmaybeformedonsurfacesbe-causeoratraceofoxygenorwatervaporaccumulatedfromtheflowinginertatmosphereduringpyrolysis.
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简介:TheRamanspectraof3%(molefraction)Y2O3-ZrO2(3Y)areobtainedatdifferenttemperaturefrom77Kto853K.Theresultsshowthat260cm-1Egand460cm-1Egmodesonthespectrashifttowardlowerwavenumberwiththeincreaseoftemperature;meanwhile,thecontinuityoftheHalfWidthatHalfMaximum(HWHM)andwavenumber(frequency)ofRamanbandsarebrokenandt-phaseonlypartiallytransformstom-phaseat523K.Basedontheexperimentalresults,thispaperdiscussesthet-phaselatticevibrationof3YandpresentstheimagesofvibrationdisplacementofsixRaman-activemodesfort-phaseofZrO2.TheanalysisindicatesthattherearediversitiesexistinginthedisplacementoftheatomicvibrationofRaman-activemodesbecauseoftheirdifferentsymmetriesatvarioustemperature,whichleadstothedifferentchangetendenciesofRamanbands.Furthermore,theabruptchangesofsomeRaman-activemodesindicatingtheatomicdisplacementareassumedtobethecondensationsofphononmodesinthet→mphasetransition.
简介:(1-x)La_(0.67)Ca_(0.33)MnO_3/Cr_2O_3(LCMO)+xCr_2O_3composites被一个新液相方法综合。XRD和SEM大小表明在LCMO结构和LCMO的晶格常数可溶的很少Cr_2O_3几乎没变化,当大多数Cr_2O_3在谷物边界或在LCMO谷物的表面上是分布式的时。Inresistivity对温度大小,金属--绝缘体转变被观察什么时候x<0.20。抵抗力增加和金属--绝缘体转变温度与Cr_2O_3的增加的内容减少。一个随机的电阻器网络(KRN)模型被使用,到模仿混合样品的运输性质。模拟结果同意试验性的观察。结果证明方法为理解maganite的composites的电子运输是合理的。
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