简介:ItiswellknownthatthephotocatalyticactivityofTiO2thinfilmsstronglydependsonthepreparingmethodsandpost-treatmentconditions,sincetheyhaveadecisiveinfluenceonthechemicalandphysicalpropertiesofTiO2thinfilms.Therefore,itisnecessarytoelucidatetheinfluenceofthepreparationprocessandpost-treatmentconditionsonthephotocatalyticactivityandsurfacemicrostructuresofthefilms.ThisreviewdealswiththepreparationofTiO2thinfilmphotocatalystsbywet-chemicalmethods(suchassol-gel,reversemicellarandliquidphasedeposition)andthecomparisonofvariouspreparationmethodsaswellastheiradvantageanddisadvantage.Furthermore,itisdiscussedthattheadvancementofphotocatalyticactivity,super-hydrophilicityandbactericidalactivityofTiO2thinfilmphotocatalystinrecentyears.
简介:TheeffectofyttriaonthesolidreactionmechanismofaCaHPO4·2H2O+CaCO3systematdifferenttemperatureswasexperimentallystud-ied.Thesampleswithandwithoutyttriaweresubjectedtothermogravimetric/differentialscanningcalorimetrymeasurement.ThesampleswereheattreatedatthetemperaturescorrespondingtothepeaksontheDSCspectra,andtheresultedphasecompositionswereidentifiedbyX-raydiffraction.Thetransformationmechanismwasdeducedbycomparingthephasesobtainedatdifferenttemperatures.Theresultsshowthatthetransformationsatbelow1073Karenotaffectedbyyttria,butallthoseatabove1073Karecompletelyaltered.Theformationtem-peratureofhydroxyapatitedecreasesby134K,andthedecompositiontemperatureincreasesby38K.ThepolymorphoustransformationofCa3(PO4)2fromβphasetoαphaseincreasesby47K.Thethermodynamicpropertiesofthetransformationsatabove1073Karealsomodi-fiedbytheadditionofyttria;thatis,theendothermalpeaksaresubstitutedbyexothermalpeaks.
简介:TiO2/Au/TiO2多层的薄电影用dc(直接水流)在房间温度在聚合物底层被扔磁控管劈啪作响方法。由改变每层的厚度,TiO2/Au/TiO2多层的电影的光、电的性质能被定制适合不同应用。厚度和Au层的光性质和Au绝缘的接口的质量为Au绝缘的多层的薄电影的电、光的表演是批评的。在8nm的厚度,Au层形成有最低抵抗力和它的连续结构一定为高发射度薄。多层的栈能被优化有6的一个表电阻?在在在波长的680nm的超过80%的发射度的/sq.。当时,山峰发射度向长波长区域变二TiO2的厚度(上面、更低)层增加。当二部TiO2电影的电影厚度是45nm时,高发射度价值为全部可见轻波长区域被获得。
简介:利用高频辅助激光熔覆技术在镍基合金上制备Al2O3-13%TiO2(质量分数)陶瓷涂层。采用SEM、XRD和EDS等方法分析陶瓷涂层的微观结构和陶瓷层与粘结层之间的结合界面。结果表明:陶瓷层出现了完全熔化区和液相烧结区双层结构,其中,完全熔化区颗粒充分烧结长大,而液相烧结区则出现了三维网状结构,该三维网状结构由熔化的TiO2相包裹Al2O3颗粒形成。通过激光熔覆作用下的粉末熔化和扁平化行为解释双层结构形成机理。同时,在陶瓷层与粘结层的结合界面上发现具有尖晶石结构的NiAl2O4和针状结构的Cr2O3,证明在激光熔覆过程中发生的化学反应可以有效增加陶瓷层与粘结层的结合强度。
简介:为提高硼的去除率,研究了电磁感应精炼过程中硼杂质在CaO-SiO2-BaO-CaF2四元渣和熔硅之间的分配系数LB,讨论了四元渣系中CaO/SiO2质量比、BaO和CaF2含量、熔炼时间对LB的影响规律。结果表明:随着CaO.SiO2渣中BaO和CaF2含量的增大,LB值增大。当CaO/SiO2质量比为1.1:1、BaO和CaF2含量分别为15%和20%时,CaO.SiO2.BaO.CaF2四元渣去除熔硅中硼杂质效果最好,LB达到最大值6.94,并且LB随着熔炼时间的延长而增大。经过两次造渣后,熔硅中硼含量由3.5×10.5降到3.7×10.6,硼的去除率达到89.4%。
简介:Inviewoftheimportanceofsolventextractionofrareearthmetalswiththeacidicorganophosphorousreagent,thedevelopmentofachemicallybasedmodelapplicabletohighconcentrationisdesired.Inthepresentstudy,theequilibriumdistributionofdysprosium(Ⅲ)betweenanaqueousnitricacidsolutionand2-ethylhexylphosphonicacidmono-2-ethylhexylester(PC88A)wasmeasuredintherangeofaninitialaqueousdysprosium(Ⅲ)concentrationfrom1.0×10-3to1.0×10-1kmol/m3andPC88Aconcentrationfrom0.16to0.65kmol/m3inShellsolD70asthediluent.Theobtaineddatawereanalyzedusingthechemicallybasedmodelinordertocorrelatetheequilibriumdistributionratios.Inthismodel,dysprosium(Ⅲ)wasassumedtobeextractedwiththePC88Adimerasa1:3complex,theactivitieswereconsideredfortheaqueousspecies,andtheeffectiveconcentrationofthePC88AdimerwascalculatedusingAlstad'sempiricalequation.Asaresult,theapparentextractionequilibriumconstantwasdeterminedtobe253(kmol·m-3)-2withanexcellentcorrelationbetweentheexperimentandcalculationresultsinthewiderangeofthelogarithmofthedistributionratiofrom-2to3.5.Inconclusion,themethodologyinthismodelwouldbeeffectiveforquantitativedescriptionofsolventextractionbehaviorofgeneralrareearthelementsaswellasdysprosium.
简介:1Cr18Ni9Ti不锈钢球头在焊接后经酸洗,表面存在粗糙的腐蚀凹坑。通过采用S-3700N扫描电子显微镜、能谱分析仪、金相显微镜等对表面粗糙的腐蚀凹坑进行成因分析。结果表明:球头在焊接过程中产生了局部敏化现象,球头的晶粒组织细于与之配合的外套螺母组织,使得球头的耐腐蚀性低于外套螺母,在酸洗去氧化皮的过程中,外套螺母与球头的焊缝区、接管嘴的焊缝区之间形成缝隙,酸洗液中的正负离子移动受到了阻滞,导致缝隙处发生严重腐蚀,最终表现为球头表面的点状腐蚀形貌。定期更换酸洗槽液,降低Cl-浓度,以及在酸洗过程中活动零件,可以减少该类腐蚀的产生。
简介:Mg–9Li–3Al–1.6Yalloyswerepreparedthroughmixturemethod.Themicrostructure,mechanicalproperties,andcorrosionresistanceoftheas-castandasextrudedalloyswerestudiedbyopticalmicroscopy(OM),scanningelectronicmicroscopy(SEM),X-raydiffraction(XRD),mechanicalpropertiestesting,andelectrochemicalmeasurement.Theas-castMg–9Li–3Al–1.6Yalloywiththeaveragegrainsizeof325lmiscomposedofb-Limatrix,blocka-Mg,andgranuleAl2Yphases.Afterextrusion,thegrainsizeoftheas-castalloyisobviouslyrefinedandreachesto75lm;thestrengthandelongationoftheextrudedalloyareenhancedby17.20%and49.45%,respectively,owingtotheirfinemicrostructureandreductionofcastingdefects.Theas-extrudedalloyshowsbettercorrosionresistancecomparedtotheas-castone,whichmayberelatedtothelowstoredenergyanddislocationdensityintheextrudedalloy,alsothehomogenizationtreatmentbeforeextrusion.
简介:0Cr18Ni9不锈钢薄壁产品在酸洗过程中易发生过腐蚀。本研究采用0.1mm厚度0Cr18Ni9不锈钢带,对酸洗的各影响因素进行试验研究,结果表明:材料状态不同,耐腐蚀能力不同,退火态更易出现过腐蚀;酸液温度、浓度及酸洗的时间均对不锈钢带腐蚀程度和力学性能有较大影响;在含HF的腐蚀剂中酸洗容易使薄壁不锈钢带力学性能降低,造成材料脆化,且HF含量越高对薄壁不锈钢力学性能影响越大。
简介:采用扫描电镜、能谱仪以及X射线衍射仪对具有WC+β(β为钴基粘结相)两相结构的WC-11Co-0.71Cr3C2-0.06RE(RE为含La、Ce、Pr、Nd的混合稀土)硬质合金烧结体表面进行观察与分析。结果表明,在烧结过程中合金中的La、Ce、Pr、Nd通过定向迁移与烧结炉内气氛中的S、O等杂质元素结合,在合金烧结体表面形成RE2S3(主)和RE2O2S(少量)弥散相。从合金中Cr3C2的热力学稳定性、Cr在Co中的溶解度特性以及稀土原子激发等3个方面,对稀土迁移活性的激发机制和稀土原子的定向迁移机制进行分析与讨论。
简介:Byuseofmicro-DTAtechniqueaswellasambientandhightemperatureX-rayanalysisthephasediagramofNaCl-CaCl2hasbeenchecked.Itis.asimpleeutecticsystemwithasolidsolubilityinthesodiumchlorideside.Theeutecticpointisat773K,49mol%NaCl.Theexperimentalresults,especiallythoseoftheX-raydiffractionstudieshaveshowedthattheincongruentcompound4NaCl-CaCl2doesnotexistintheNaCl-CaCl2system.
简介:ThelongafterglowSrAl2O4:Dy,Euphosphorisliabletohydrolyzeinwaterwithdeteriorationoftheluminescentproperty.SrAl2O4:Dy,Euphosphorswerethereforeheatedat60-90℃inTEOSsoltoformasurfacegelandthenheat-treatedat400℃toobtainSiO2coatedphosphors.ObservationbyTransmissionElectronMicroscope(TEM)andX-rayphotoelectronspectroscopy(XPS)showsthatathinsilicafilmformsonthesurfaceofthephosphors.Thecoatingprocedurecanbeillustratedbyafour-stepprocessandthetransparentsilicafilmcansuppressthehydrolysisprocess,sothattheluminescentpropertiesofthephosphorsareunimpairedorevenbetter.
简介:TooptimizethemagneticpropertiesofnanocompositeNd9Fe85B6magnets,theas-quenchedribbonswithdifferentmicrostructureswerepreparedatsixwheelvelocitiesfrom10to30ms-1throughrapidquenching,followedbyaseriesofannealingtreatmentsat550–800°Cfor5–10min.Itisfoundthatboththelargeinitialgrainsatlowcoolingrateandhighcontentofamorphousphaseathighcoolingratecausea-Fegrainscoarsening,whichleadstoadeclineinthestrengthofexchangecouplinginteractionandthedeteriorationofmagneticproperties.Inordertooptimizethemagneticproperties,theas-quenchedribbonsshouldbechosenwithrelativelysmallinitialgrainsaswellasasmallamountofamorphousphase.FornanocompositeNd9Fe85B6materials,theoptimizedmagneticpropertiesofHcj=446kAm-1,Br=0.86T,(BH)max=80kJm-3areobtainedforribbonspreparedat18ms-1afterannealingat620°Cfor5min.
简介:InorganicbufferlayerssuchasSiO2orTiO2andtransparentconductiveindium-tin-oxide(ITO)filmswerepreparedonpolyethyleneterephthalate(PET)substratesbyionassisteddeposition(IAD)atroomtemperature,andtheeffectsofSiO2andTiO2onthebendingresistanceperformanceofflexibleITOfilmswereinvestigated.TheresultsshowthatITOfilmswithSiO2orTiO2bufferlayerhavebetterresistancestabilitiescomparedtooneswithoutthebufferlayerwhentheITOfilmsareinwardsbentatabendingradiusmorethan1.2cmandwhentheITOfilmsareoutwardsbentatabendingradiusfrom0.8cmto1.2cm.ITOfilmswithSiO2bufferlayerhavebetterresistancestabilitiescomparedtooneswithTiO2bufferlayeraftertheITOfilmsarebentseveralhundredsofcyclesatthesamebendingradius,fortheadhesionofSiO2isstrongerthanthatofTiO2.ThecompressivestressresultedfrominwardbendingleadstotheformationofmoredefectsintheITOfilmscomparedwiththetensilestressarisingfromoutwardbending.SiO2andTiO2bufferlayerscaneffectivelyimprovethecrystallinityofITOfilmsin(400),(440)directions.