简介:EmployingLi2CO3,NiO,Co3O4,andMnCO3powdersasstartingmaterials,Li[Ni1/3Co1/3Mn1/3]O2wassynthesizedbysolid-statereactionmethod.Variousgrindingaidswereappliedduringmillinginordertooptimizethesynthesisprocess.Aftersuccessiveheattreatmentsat650and950℃,thepreparedpowderswerecharacterizedbyX-raydiffraction(XRD)analysis,scanningelectronmicroscopy,andtransmissionelectronmicroscopy.Thepowderspreparedbyaddingsalt(NaCl)asgrindingaidexhibitaclearR3mlayerstructure.ThepowdersbyothergrindingaidslikeheptaneshowsomeimpuritypeaksintheXRDpattern.Theformerpowdersshowauniformparticlesizedistributionoflessthan1μmaveragesizewhilethelattershowsawidedistributionrangingfrom1to10μm.EnergydispersiveX-ray(EDX)analysissshowthattheratioofNi,Co,andMncontentinthepowderisapproximately1/3,1/3,and1/3,respecively.TheEDXdataindicatenoincorporationofsodiumorchlorineintothepowders.Charge-dischargetestsgaveaninitialdischargecapacityof160mAh·g-1forthepowderswithNaCladditionwhile70mAh·g-1forthepowderswithheptane.
简介:"GasTransmittingFromWesttoEastProject"issignificant.Itshouldensuretheweldingqualityandsafetyofpipeline.Thetaskisveryarduoustoguaranteethequalityoftheprojectintheconditionoflongline,complexweatherandgeologyfeatures.Inthispaper,theweldingcoldcrackingsusceptibilityofdomesticX-70pipelinesteeladoptedbytheproject,whichisoneofthemostinterestingquestionsofweldingqualityaboutpetrolpipeline,wasstudiedbymeansofobliqueY-groovecrackingtest.Thecrackratioofsurfaceandsectionwastestedundertheconditionsofdifferentweldingmaterialsandpreheattemperature.TheX-70pipelinesteelhasgoodcrackresistance.Theresearchhasimportantvaluefortheconstructionoflarge-scalepipelineengineeringandtheapplicationofdomesticX-70pipelinesteel.
简介:ThesusceptibilityofweldedjointfortheX65pipelinesteeltoH2Sstresscorrosioncracking(SCC)isinvestigated.SCCtestsonthesteelarecarriedoutintheenvironmentbasedonNACETM-01-77solutionwithsaturatedgaseousH2S.Thethresholdstressintensityfactorandcrackpropagationvelocityarecalculatedaccordingtowedge-openingloading(WOL)specimens.Thethree-dimensionalelastic-plasticfiniteelementanalysisofWOLspecimensisperformedbyusingtheFEMprogrammingpackageANSYS.Stressfieldandconcentrationofhydrogendistributionpropertyaheadofthecracktipareobtained.ThispapersurveyedthemicrostructureofweldedjointandstudiedonthemechanicalpropertiesofX65pipelinesteel.Itprovidesexperimentalbasisforstudyingstresscorrosion.Theresultsofnumericalanalysisareconsistentwithconclusionsofstresscorrosiontest.
简介:Anewseriesofrareearthcompounds,Y2-xErxMo4O15(x=0.0-2.0),weresynthesizedandtheirstructuresweredeterminedbypowderX-raydiffraction(XRD).RietveldanalysisofXRDpatternsrevealsthatthecompoundsofthisseriescrystallizeinmonoclinicsystemwithspacegroupP21/c.Thelatticeparametersa,b,c,βandtheunitcellvolumeVde-creaselinearlywithincreasingErcontent.Thethermalexpansionpropertiesofthesecompoundswerestudiedunderhigh-temperatureXRD.PositivethermalexpansionsofcompoundsY2-xErxMo4O15arefoundtobeanisotropicalongthethreecrystallographicdirectionswhereaandcaxesexpandwhilebaxiscontractsinthewholetemperaturerange.Byanalysisofdata,theexpansionofweakbandMo2-O14withrisingtemperatureshouldberesponsibleforpositivethermalexpansion.
简介:TheintermetalliccompoundZr1-xTixCowaspreparedanditssuitabilityforhydrogenstoragewasinvestigated.ThealloysobtainedbymagneticlevitationmeltingwiththecompositionofZr1-xTixCo(x=0,0.1,0.2and0.3,at.%)showsinglecubicphasebyX-raydiffraction.Asingleslopingplateauwasobservedoneachisothermal,andpressure-composition-temperature(PCT)measurementresultsshowthattheequilibriumhydrogendesorptionpressureofZr1-xTixCoalloyincreaseswithincreasingTicontent.Thedesorptiontemperaturesforsupplying100kPahydrogenareabout665,642,621and614KforZrCo,Zr0.9Ti0.1Co,Zr0.8Ti0.2CoandZr0.7Ti0.3Coalloy,respectively.RepeatedhydrogenabsorptionanddesorptioncyclesdonotgenerateseparatedZrCo,TiCoandZrH2phases,indicatingthatalloyshavegoodthermalandhydrogenstabilization.