简介:Theeffectofpromotercobaltandthesequencesofaddingcobaltandmolybdenumprecursorsontheperformanceofsulfur-resistantmethanationwereinvestigated.AllthesesampleswerepreparedbyimpregnationmethodandcharacterizedbyN2-adsorption,X-raydiffraction(XRD),temperature-programmedreduction(TPR)andlaserRamanspectroscopy(LRS).TheconversionsofCOforMo-Co/Al,Co-Mo/AlandCoMo/Alcatalystswere59.7%,54.3%and53.9%,respectively.Amongthesecatalysts,theMo-Co/AlcatalystpreparedstepwiselybyimpregnatingMoprecursorfirstlyshowedthebestcatalyticperformance.Meanwhile,theconversionsofCOwere48.9%forMo/Alcatalystand10.5%forCo/Alcatalyst.TheadditionofcobaltspeciescouldimprovethecatalyticactivityofMo/Alcatalyst.TheN2-adsorptionresultsshowedthatCo-Mo/Alcatalysthadthesmallestspecificsurfaceareaamongthesecatalysts.CoMoO4speciesinCoMo/AlcatalystweredetectedwithXRD,TPRandLRS.Moreover,crystalMoS2whichwasreportedtobelessactivethanamorphousMoS2wasfoundinbothCo-Mo/AlandCoMo/Alcatalysts.Mo-Co/Alcatalystshowedthebestcatalyticperformanceasithadanappropriatesurfacestructure,i.e.,nocrystalMoS2andverylittleCoMoO4species.
简介:为了减少锂离子电池正极材料与电解液的相互作用,用沉淀法在LiNi0.8Co0.2O2表面包覆一层Al2O3,并通过电化学测试、扫描电镜和X射线衍射研究其表面形貌和晶体结构。结果表明,经过表面包覆后,有效地抑制了电解液对正极材料的侵蚀,虽然初始放电容量略有降低,但循环性能明显改善;Al2O3包覆量对LiNi0.8Co0.2O2电化学性能存在影响,包覆量为0.7%(质量分数)的样品性能最优。
简介:以六水合氯化钴(CoCl2·6H2O)和水合三氯化钌(RuCl3·3H2O)为前驱体,采用胶体法制备超级电容器用(RuO2/Co3O4)·nH2O复合薄膜电极材料。用X射线衍射仪以及CHl660C电化学工作站对该复合薄膜的物相结构及电化学性能进行表征。结果表明:当COCl2'6H20和RuCl3·3H2O的物质的量比n(Co):n(Ru)为2:1时,于350℃下热处理2.5h制备的复合薄膜电极具有优良的性能,在浓度为0.5mol/L的H2S04电解液中其比电容达到512F/g,500次充放电循环后比电容量保持在充放电循环前的96.1%;充放电电流为0.01A时,内阻为1.2Ω。
简介:UsingAl2O3-MgOcastableinlargeladlecanavoidcontainationofmoltensteelfromcarbon-containingrefractoriesandincreasladleservicliferemarkably,Theadditionofmagnesiaandfinepowder,theeffectofgrainsizeontheproper-tiesofthecastable,especiallylinearchangeandstructurespallinghavebeenstudied,Castablepro-duedforlargeladlewithsmallweareratehasgotgoodapplicatioresult.
简介:采用粉末冶金方法制备含Y2O3的稀土钼合金,利用金相显微镜、扫描电子显微镜(SEM)、X射线衍射(XRD)、能谱分析(EDS)等手段对钼合金的断裂特征和组织结构进行对比分析,研究稀土氧化物Y2O3含量对钼合金组织和性能的影响。研究表明:添加Y2O3能细化晶粒、改善钼合金的晶粒均匀性和致密度、提高钼合金的性能;拉伸强度和屈服强度随Y2O3含量的增加呈现先增高后降低的趋势,在Y2O3含量为1%时,抗拉强度达511.43MPa,屈服强度456.99MPa,分别是纯钼材料的1.31倍和1.57倍,综合力学性能最佳;在烧结坯中,Y2O3颗粒分布均匀,主要以球形和等轴状形式存在于晶界上。
简介:Theimplantedionrange,thedepthprofileandthefilmsttuctureoftheimplantedlayerwerestudied;thecarrierconcentrationandthemobilityweremeasured;theconductivitymechanismofthefilmimplantedFeintoAl2O3ceramicwasdiscussed.TheconclusionisthattheimplantedFe2+ionsmoveintoAl2O3latticeandreplaceAl3+toformsubs-titutionimpuritiessothattheionimplantedlat-tice,ascomparedwiththeoriginalone,presentsaneffectivenegativechargewhichformsanegativechargecenter.Avacancyisboundarroundit,andanacceptorisintroducedintheforbiddenband.
简介:AnapplicatiopnoftheopticalpyrometerisstudiedformeasuringmonochromaticemissivitiesofcementclinkerwithvariousFe2O3contnet.Theidsaofusing“brightnesstemperature”isintroducedintotheeimssivitymeasurement.Inthismethod,thereisnoneedformeasuringanactualtemperatureofsamplesurfaces,onlywithdeterminingbothbrightnesstemperaturesofasampleandablackbodycantherequiredemissivitybeevaluatedaccordingtoWien'sradiationlaw.Inpractice,thecementclinkerisregardedasagreybody,themonochromaticemissivityisapproximatelyequaltothetotalemissivity,soasingle-colouropticalpyrometerisappliedforthispurpose,Testmeasurementsarecarriedouton10kindsofcementclinkers,Experimentaldataaretreatedbytheleastsquaremethod.Asaresult,theemissivityvariationwithtemperatureatacertainFe2O3contentisquitewellrepresentedbyεn=a+bT.Furthermore,thisworkfirstreportedthattheeimissivitiesofcementclinkerchangeconsierablywithFe2O3contents.Inmultiplecementproductionthisconclusionisveryimportant.
简介:摘要采用溶胶-凝胶法制备了Al2O3-ZrO2复合溶胶膜,研究了化学组成和添加剂对复合溶胶的影响。结果表明,当Al2O3/ZrO2=1,DMF=40vol%时,可得到澄清透明,粘度适中,稳定性好,且凝胶干燥后几乎无开裂的溶胶膜
简介:Cr2O3canbesinteredwellat1500℃incarbon-embeddedconditionorH2atmosphere.Butthehighchromebearingrefractoriescannotreachdensificationwhensinteredat1700℃for10hinweakreducingatmosphereformedbythecombustionoffuel,anditsapparentporosityisabout18%.Thehighchromebearingrefractoriesaremainlyusedincoalgasifiers.Thetemperatureinthefurnaceisabout1500℃andtheproductsareH2andCO,whicharejustthesinteringconditionsofthedensechromerefractorieswithapparentporositylessthan10%.Thehighchromebearingrefractoriesusedincoalgasifiersmaybesinteredagainandthenshrink,destroyingthegasifierlining.Thethermodynamiccalculationshowsthatitissafeaboutthehighchromebearingrefractoriesusedingasifiers.Itisalsoexplainedthatthehighchromebearingrefractoriescan’tbesintereddenselyinweakreducingatmosphereformedbythecombustionoffuel.Thenewsinteringtechnologiescanbeusedtoimprovethebulkdensityofthehighchromebearingrefractories.