简介:CuO-CoO-MnO/SiO2nanocompositeaerogels被经由大音阶的第五音胶化过程和乙醇supercritical弄干技术作为先锋把tetraethylorthosilicate(TEOS)用作Cu,公司和Mn醋酸盐的Si来源,和水的答案准备。gelatination机制被原子磁性的回声(NMR)和X光检查光电子光谱学(XPS)调查。CuO-CoO-MnO/SiO2nanocompositeaerogels的微观结构和作文被扫描电子显微镜学(FE-SEM)的地排放描绘,传播电子显微镜学(TEM),电子散光谱学(版本)和XPS。特定的表面区域,毛孔尺寸和nanocompositeaerogels的毛孔尺寸分发被Brunauer-Emmett-Teller(赌注)方法决定。产品被煤气的层析(GC)分析。结果证明CuO-CoO-MnO/SiO2nanocompositeaerogels是多孔的,与10150nm,216nm的毛孔尺寸分布,7.68nm的一种平均毛孔尺寸,和664.4695.8m2/g的一个特定的表面区域的粒子尺寸分布。在nanocompositeaerogels的转变金属的臼齿的部分是0.71%-13.77%。这种结构是有利的不仅增加装载催化剂,而且作为cocatalysts充分利用转变金属氧化物的效果;CuO-CoO-MnO/SiO2nanocompositeaerogels能在diphenyl碳酸盐的更安全、环境友好的合成和催化作用的另外的地被用作一个新奇催化剂搬运人。
简介:TheCurietemperatureof(Nd1-xPrx)2Fe14CoyBcompounds(x=0,0.2,…,1.0andy=O,2,4,6,14)hasbeendeterminedwithACinitialsusceptibilitymeasurement.ItwasfoundthatthevariationsofCurietempera-turewithxisnotlinearfory=0and14,whereasitislinearforothervaluesofy.Thelatticeconstantsof(Nd1-xPrx)2Fet14BweredeterminedbyusingX-raydiffraction.Thelatticeexpansionwasmostlyalongthecaxis,whereasthatalongthea-axisremainedpracticallyzeroforthewholeseries.ItissuggestedthatPratomsmayshowsitepreferenceinR2M14Bcompounds(M=FeorCo).DuetothesubstitutionofCoforFe.thetendencyofsitepreferenceofPrbecomeslesspronounced,whichmaybeattributedtothedecreaseofdiffer-enceofcrystalelectricfield(CEF)actingonthetworareearthsiteswiththeintroductionofCoorFe.Incon-trasttothatofthePratoms,thesitepreferenceofCoiu(Nd(1-x)Prx)2Fe(14-y)CoyBcompoundsdoesnotdependonthecompositionoftherareearthsublattice(R=NdorPr).
简介:在Ce1-xDyx-ySryO2-δ体系中,研究了Dy和Se对总离子电导率的影响。在该体系中,使用麦芽糖和果胶作为有机前驱体,通过改性溶胶-凝胶工艺,在x=0.15,y=0.015,0.03和0.045的条件下,制备不同组分的导电体。采用X射线衍射谱的Rietveld拟合验证了导电体具有空间群Fm3m的立方结构。从SEM像可以看到具有明显晶界、相对均匀的晶粒。在150-500℃的温度范围和40Hz-1MHz的频率范围内,采用四探针交流阻抗法测量导电体的总离子电导率。与单掺杂的二氧化铈样品相比,Ce0.85Dy0.12Sr0.03O2-δ具有更高的电导率。
简介:HotcompressionbehaviorofTiC–Al2O3/AlcompositeswasstudiedusingtheGleeble-1500systematatemperaturerangeof300–550°Candatstrainraterangeof0.01–10.00s-1.TheassociatedstructuralchangeswerestudiedbyTEMobservations.Theresultsshowthatstressleveldecreaseswithdeformationtemperatureincreasingandstrainratedecreasing,whichcanberepresentedbyaZener–Hollomonparameterinanexponent-typeequationwithhotdeformationactivationenergyQof172.56kJ·mol-1.Dynamicrecoveryoccurseasilywhenstrainratesarelessthan10.00s-1.Dynamicrecrystallizationcanoccuratstrainrateof10.00s-1.
简介:NanocrystallineMg2Ni-typealloyswithnominalcompositionsofMg20Ni10–xCux(x=0,1,2,3,4,massfraction,%)weresynthesizedbyrapidquenchingtechnique.Themicrostructuresoftheas-castandquenchedalloyswerecharacterizedbyXRD,SEMandHRTEM.Theelectrochemicalhydrogenstorageperformancesweretestedbyanautomaticgalvanostaticsystem.ThehydridinganddehydridingkineticsofthealloysweremeasuredusinganautomaticallycontrolledSievertsapparatus.Theresultsshowthatalltheas-quenchedalloysholdthetypicalnanocrystallinestructureandtherapidquenchingdoesnotchangethemajorphaseMg2Ni.Therapidquenchingsignificantlyimprovestheelectrochemicalhydrogenstoragecapacityofthealloys,whereasitslightlyimpairsthecyclingstabilityofthealloys.Additionally,thehydrogenabsorptionanddesorptioncapacitiesofthealloyssignificantlyincreasewithrisingquenchingrate.
简介:这份报纸在极其细小的颗粒的WC-12%Co合金的磁性、机械的性质上处理codopedVC/Cr3C2和sintering温度的效果。结果证明在最佳的比例的做的VC/Cr3C2的synergistic行动提高坚硬和合金的横向的破裂力量(TRS),与更多的同类的微观结构。当合金是在1430点的sintered时?C并且与0.5%Cr3C2/0.2%VC,TRS到达3786MPa,坚硬是91.7HRA和比0.6m小的谷物尺寸。谷物生长上的数字分析在sintering过程期间证明在WC谷物边界并且Cr3C2溶解在公司上猛抛的两VC分阶段执行减少固体/液体的界面的精力,溶解和降水的过程极大地被延迟,WC谷物变粗被禁止。
简介:AZr-1.15wt%Cr-0.10wt%Fealloywasbeta-quenchedfrom1050℃toproduceasupersaturatedα′-phase,andthenheatedforvaryingtimesattemperaturesfrom650℃to760℃toprecipitateZr(CrFe)2.Athermoelectricpower(TEP)techniqueandtransmissionelectronmicroscopy(TEM)wereusedtomonitorthisprecipitationprocess.UsingtheJohnson-Mehl-Avramiequation,theTEPresultsandalineregressionmethod,theactivationenergyfordiffusionandthediffusioncoefficientofchromium(andFe)inα-Zrhavebeencalculatedover650℃~760℃.Thetemperaturedependenceofthediffusioncoefficient,DCr/α(cm2/s)isdescribedat650℃~760℃bytherelationshipformula.ThecoarseningoftheZr(CrFe)2particlesshowsat1/2dependenceofmeanparticlesizeonagingtime,t.Suchatimedependenceistypicalofcoarseningwhereatomtransferacrosstheinterfaceisrate-controlling.
简介:在自我组织的TiO2nanotubes(Pt-TiO2/Ti)上支持的铂nanoparticles用cathodic减小跟随的电气化学的阳极的氧化被准备。结构和Pt-TiO2/Tielectrocatalyst的化学自然被X光检查衍射(XRD)和扫描电子显微镜学(SEM)调查。XRD和SEM结果在nanotubularTiO2上显示铂的存在。磅存款的稳定性被周期的voltammetry也在0.5mol/LH2SO4答案调查。当退火了到锐钛矿时,Pt-TiO2/Ti催化剂的electrocatalytic活动在甲醇的电镀物品氧化期间展出改进效果。Pt-TiO2/Tielectrocatalyst上的甲醇氧化的连续周期的voltammograms看唯一的electrocatalytic特征是否与体积磅催化剂上的甲醇氧化相比。当一部electroactive电影的形成发生到工作催化剂表面上时,这因为由自我组织的TiO2nanotubes上的磅粒子的磅(111)方面的吸附的公司的进一步快的氧化。
简介:Byanoveltechnique-cathodicmicro-arcelectro-deposition(CMED),ZrO2coatingsweredepositedonanFeCrAlalloy.ExperimentalresultsshowthatthenecessaryconditionsforobtainingZrO2coatingsaretoapplyapulsepeakvoltageoveracriticalvalueandaddmoderateamountsofZrO2colloidalparticlesandZr(NO3)4intheequeoussolution.Theas-depositedcoatingsareporousbecausehydrogen,water,andothervaporsaregeneratedandreleasedfromthecoatingstothesolutionduringthesparkreaction.ThecoatingscontainmonoclinicandtetragonalcrystallineZrOwithcertaindegreeofamorphousstructure.TheprocessingparametersandmechanismofCMEDwerediscussed.
简介:Aseriesoftheelectrochemicalandlong-termcorrosiontestswascarriedoutina3.5wt%Na2SO4solutiononthermal-sprayedWC-17CoandWC-10Co-4Crcermetcoatingsinordertoexaminetheeffectofcompositionofbindermaterialsonthecorrosionbehavior.TheresultsrevealthattheoverallcorrosionresistanceoftheWC-17CocoatingisinferiortothatoftheWC–Co–CrcoatingsduetothecorrosionofbindermaterialswhichinduceWCparticlestofalloff.CoOandWO3oxidefilmsformonthesurfaceofWC-17CocoatinginNa2SO4solutionelectrochemicalcorrosionprocess,whichwillprotectthecoatingintheprocessofcorrosion.Cr2O3oxidefilmformedontheWC-10Co-4Crcoatingsurfacehasastronghinderedroletocorrosion.ThecorrosionmechanismofWC-17CocoatinginNa2SO4solutionisentirecorrosionofComatrix,whileitisfilm-holecorrosionmechanismforWC-10Co-4Crcoating.
简介:提出一种合成γ-LiAlO2的替代解决方案—改进燃烧法直接合成γ-LiAlO2,并将其用于相对简单的反应体系中,原料为非氧化性化合物如Al2O3和LiOH,燃料为尿素。采用1:1、1.5:1和2:1的非化学计量Li/Al摩尔比,在900和1000°C下反应5min,制备LiAlO2,并对其组织和结构进行表征。考察Li/Al摩尔比对材料形貌和高γ射线辐照下材料稳定性的影响。结果表明,所得粉体的晶体结构为?-LiAlO2和?-LiAlO2,其取决于Li/Al摩尔比。因此,用该方法可以成功合成微砖状、多面体状和层状?-LiAlO2,而无需任何后续处理。γ辐照结果表明,所得到的?-LiAlO2不分解,只形成少量的Li2CO3;由此可以确定,辐照会导致固结,不利于氚的有效提取;结果证明,用燃烧法生产高纯度?-LiAlO2不需要硝酸盐前驱体。
简介:ExtractingB2O3fromcalcinedboronmud(CBM)wasstudied.TheeffectoffactorssuchasreactiontemperatureandNaOH-to-CBMmassratioonB2O3extractionefficiencywasinvestigated.TheresultsshowthatincreasingreactiontemperatureandNaOH-to-CBMmassratioincreasesB2O3extractionefficiency.TherearetwostagesfortheB2O3extractingprocess:0–20ministhefirststage,whichisrapid;20–50ministhesecondstage,whichisslowerthanthefirststage.Theoverallextractingprocessfollowstheshrinkingcoremodel,andthefirstandsecondstagesaredeterminedtoobeythesurfacechemicalreactionmodelandthediffusionthroughtheproductslayermodel,respectively.Theactivationenergiesofthefirstandsecondstagesarecalculatedtobe41.74and15.43kJ·mol-1,respectively.TheB2O3extractingkineticsequationsofthefirstandsecondstagesarealsoobtained.
简介:钛氧化物涂层被微弧的氧化(毛)在Ti-2Al-2.5Zr合金底层上综合技术。涂层的表面特征被扫描电子显微镜学学习。当分泌物隧道尺寸随对待时间的增加清楚地增加时,Ti-2Al-2.5Zr合金的微弧的分泌物隧道减少。随涂层厚度的增加,多孔的层厚度显然增加。涂层的表面层的阶段作文被X光检查衍射和X光检查光电子光谱学评估。XRD和XPS分析的结果证明毛涂层主要由锐钛矿和金红石TiO2组成。