简介:TheZrO2-Al2O3ceramiccompositeswerepreparedbyappropriatetechniqueswithcommercialZrO2andAl2O3powdersasrawmaterialsandY2O3asstabilizer.TheresultsindicatethatwiththeintroductionofAl2O3intotheZrO2matrixwherethequantityofadditiveY2O3is3.5%(molefraction),thegrowthofZrO2grainsisefficientlyinhibited,whichhelpstheZrO2grainsexistinametastabletetragonalmanner;thushigherstrengthandtoughnessareacquired.Whenthecontentofaluminais20%(massfraction),thebendingstrengthandfracturetoughnessofthecompositesare676.7MPaand10MPa·m1/2respectively,themechanicalbehaviorsareclosetothosepreparedwithZrO2andAl2O3powderssynthesizedthroughwetchemicalapproach.Themechanicalbehaviorsofthecompositesarewellimprovedowingtothedispersiontougheningofaluminagrainsandphasetransformationtougheningofzirconiagrains.
简介:研究不同碳源下Al2O3-SiC-C铁钩料的性能。分别以球沥青、焦炭和炭黑为碳源,比较了常温下三者的显气孔率、抗折和抗压强度。结果表明,不同种类碳源将对试样的气孔率和抗折强度产生不同程度的影响。
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简介:Inthepresentstudy,sampleswereextensivelycollectedthroughoutthestainlesssteelmanufacturingprocess.Thethree-dimensionalmorphologyofinclusionswasrevealedbynon-aqueoussolutionelectrolysis.Thehighconcentrationofaluminuminferrosiliconcausedtheincrementof[Al]sinsteelandAl2O3ininclusions,whichledtothehighermeltingtemperatureofinclusions.ItwasconcludedthattheapplicationoflowAlferrosiliconandcalciumtreatmentcouldpreventtheformationofAl2O3-richinclusions.
简介:以异丙醇铝为前驱体,HNO3为胶溶剂,采用溶胶-凝胶法制备Al2O3膜。考察HNO3浓度对溶胶及薄膜的影响,通过TG-DTG,XRD,AFM,BET等表征手段对溶胶的稳定性及黏度,薄膜的热稳定性,物相组成,表面形貌,微孔结构及分布等进行综合分析。结果表明:随HNO3浓度增大,溶胶黏度增大,HNO3浓度为5mol/L时溶胶发生团聚;薄膜的热稳定性较好,高于500℃加热薄膜几乎没有质量损失;随烧结温度升高,薄膜中的γ-AlOOH逐渐向γ-Al2O3转变,薄膜因此变得更加稳定;薄膜表面较为平整,微孔分布均匀,平均孔直径为4.22nm。
简介:ToimprovethemechanicalpropertiesofWC-Al2O3composites,theeffectsoftraceamountofCeO2additivesonthemicrostructureandmechanicalpropertiesoftheWC-Al2O3compositespreparedbyhotpressingwereinvestigated.TheresultsrevealedthattheWC-Al2O3compositesdopedwith0.1%CeO2possessedrefinedmicrostructureandenhancedmechanicalpropertiescomparedwiththatoftheundopedWC-Al2O3composites.TraceCeO2suppressedthedecarburizationofWC,promotedthemicrostructuralrefinement,andimprovedtheinterfacecoherenceoftheWCmatrixandAl2O3.When0.1%CeO2wasaddedtotheWC-Al2O3composites,theeffectofCeO2resultedintheachievementofarelativedensityof98.82%withanexcellentVickershardnessof16.89GPa,combiningafracturetoughnessof9.85MPa·m1/2withanacceptableflexuralstrengthof1024.05MPa.
简介:在甲烷(POM)的部分氧化的催化活动和稳定性混合方法的CeO2-ZrO2和-Al2O3的影响在Ni/Ce0.7Zr0.3O2-Al2O3催化剂上被调查。催化剂被XRD,TPR,H2-chemsorption,和TG-DTA描绘。为新鲜催化剂,结果证明混合催化剂(原子)的盐先锋比混合方法(摩尔)和机械地混合方法(MECH)的粉末的催促的人准备的催化剂介绍了更好的性能。XRD的结果建议在在原子样品的CeO2-ZrO2和Al2O3之间的相互作用比其它强壮,它导致了更多的格子缺点和从而更好的起始的活动。而且,MECH样品在24h稳定性测试有最好的稳定性和最少的焦炭免职。TPR和H2-chemsorption的结果显示在MECH样品的Ni-Al的亲密接触提高了抵抗焦炭免职和金属sintering的能力。
简介:采用无压烧结法制备含CeO2的Mo/Al2O3材料,用MM-200型环-块式摩擦磨损试验机测试该材料在滑动干摩擦条件下的磨损行为,通过X射线衍射(XRD)和电子探针对其微观结构和磨损后的形貌进行研究和分析。结果表明,添加CeO2的烧结样品中出现CeAl11O18相,且随CeO2含量(体积分数)增加,CeAl11O18逐渐增多,Al2O3相应减少。当CeO2的体积分数为6%时Al2O3全部由CeAl11O18取代;CeO2的添加使Al2O3和CeAl11O18相边界处均呈现圆钝形貌,并且存在Mo、Al、O的相互扩散区域。磨损形貌表明,1730℃烧结的样品中出现摩擦转移层,当CeO2含量达到4%时,该摩擦转移层大量出现,从而改善材料的耐磨性。
简介:ThemorphologyandcorrosionbehaviorofNi/Al2O3compositecoatingspreparedusingdouble-pulsedelectrodepositingtechniqueafteroxidizedunder800℃NaCldepositinairenvironmentwereanalyzedbyscanningelectricalmicroscope(SEM),X-raydiffraction(XRD)andenergydispersivespectrum(EDS).TheresultsshowedthatthecorrosionofallcompositecoatingswasacceleratedunderNaCldeposits,andthecorrosionproductswereratherporouswithpooradherencetothematrix.Al2O3particlesinthecoatingscanrefinethegrainsizeandimprovethehightemperaturecorrosionresistanceofthecoatings.Withinthetestscope,themoreAl2O3particlesinthecoatings,thelowercorrosionratescouldbeobtained,andthecorrosionmechanismwasalsodiscussed.
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:Aseriesofnovelbluelong-lastingphosphorescencephosphorsSr6Al18Si2O37:Eu2+,RE3+(RE3+=Ho3+,Gd3+,Dy3+andPr3+)werepreparedbytheconventionalhigh-temperaturesolid-statereactioninareductiveatmosphere.TheirpropertiesweresystematicallyinvestigatedutilizingX-raydiffraction(XRD),photoluminescence,phosphorescenceandthermoluminescence(TL)spectra.ThephosphorsemittedbluelightthatwasrelatedtotheemissionofEu2+dueto5d-4ftransition.Brightbluelong-lastingphosphorescence(LLP)couldbeobservedaftertheexcitationsourcewasswitchedoff.Fortheoptimizedsample,thebluelong-lastingphosphorescencecouldlastfornearly4hinthelightperceptionofthedark-adaptedhumaneye(0.32mcd/m2).TheeffectsofRE3+ionsonphosphorescencepropertiesofthephosphorswerestudied,andtheresultsshowedthattheco-dopingofRE3+ionsgreatlyenhancedtheintensityofthepeakaround315Kwhichwasrelatedtothelonglastingphosphorescenceofthephosphorsatroomtemperatureandconsequentlyimprovedtheperformanceofthebluephosphorescencesuchasintensityandpersistenttime.
简介:以纳米Al2O3和纳米Ti(C,N)为主要原料,以Mo和Ni粉等为助烧剂,采用N2气氛保护热压工艺制备Al2O3基复合金属陶瓷模具材料。采用XRD和SEM分析材料的物相组成及微观结构,并测试材料的力学性能。结果表明,当烧结温度为1660℃,纳米Al2O3质量分数为74.5%,纳米Ti(C,N)粉为20%、Mo+Ni粉为5%时,所制备的Al2O3基复合金属陶瓷模具材料性能最佳,其相对密度为98.14%,弯曲强度值为795.98MPa,硬度值为18.52GPa,断裂韧性为8.05MPa·m^1/2。第二相的引入和晶界处Mo+Ni的共同作用,可增强晶界强度,促进沿晶裂纹向穿晶裂纹转变,从而提高材料的力学性能。