简介：ＥｌｅｃｔｒｏｃｒｙｓｔａｌｌｉｚａｔｉｏｎＭｅｃｈａｎｉｓｍｏｆＴｕｎｇｓｔｅｎｉｎＭｏｌｔｅｎＫＦ－Ｂ＿２Ｏ＿３－Ｋ＿２ＷＯ＿４ＷｅｎＺｈｅｎｈｕａｎａｎｄＬｉＧｕｏｘｕｎ文振环，李国勋（ＧｅｎｅｒａｌＲｅｓｅａｒｃｈＩｎｓｔｉｉｕｔｅｆｏｒＮｏ...

简介：Thesegregationanddiffusionofboronduringheattreatmentswerestudied.Theinfluenceofboroncontents,agingtimeandappliedstressonFeMo2B2formationwasalsostudied.Finally,theeffectsofboroncontentsandFeMo2B2formationonthehightemperaturestrengthwerestudied.Boronatomsweresegregatedtoprioraustenitegrainboundaryduringnormalizingtreatment.Andtheseboronatomswereslowlydiffusedintothegraininteriorduringtemperingandagingat700℃.TheFeMo2B2phasewasonlyformedafter1,000hagingat700℃inalloycontaining196ppmboron.TheformationofFeMo2B2phaseisacceleratedbytheappliedstress.ItwasexpectedthattheformationofFeMo2B2iscloselyrelatedtotheredistributionofboronatoms.Thetensilestrengthsat700℃areincreasedwiththeincreaseofboroncontents.However,theformationofFeMo2B2phaseresultsinlowertensilestrength.

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：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：B2Gold公司日前宣布完成尼加拉瓜ElLimon金矿扩建可研。目前E1Limon金矿整个矿区保有黄金资源储量达到1700万盎司，矿山中心区（Centralzone）保有黄金矿石量513万吨，中心区探明黄金储量81．2万盎司，探明矿石黄金平均品位4．92克/吨。

简介：为改善La-Mg-Ni系A2B7型合金的电化学贮氢性能，在合金中添加一定量的Si元素，通过真空熔炼及退火处理的方法制备La0.8Mg0.2Ni3.3Co0.2Six（x=0-0.2）电极合金。研究Si元素的添加对合金结构及电化学贮氢性能的影响。结果表明，铸态及退火态合金均为多相结构，分别为Ce2Ni7型的（La,Mg）2Ni7相和CaCu5型的LaNi5相以及少量的残余相LaNi3。Si元素的添加没有改变合金的主相，但使得合金中的（La,Mg）2Ni7相减少而LaNi5相增加。添加Si显著地影响了合金的电化学性能。随着Si含量的增加，铸态及退火态合金的放电容量逐步降低，但循环稳定性却随着Si含量的增加而增强。此外，合金电极的高倍率放电性能、极限电流密度、氢扩散系数以及电化学交流阻抗谱的测试均表明合金的电化学动力学性能随着Si含量的增加先增加而后减小。

简介：ＣｕｒｉｅＴｅｍｐｅｒａｔｕｒｅｏｆＡｍｏｒｐｈｏｕｓＦｅＳｉＢａｎｄＦｅＷＳｉＢＡｌｏｙｓＷａｎｇＬｉｎｇｌｉｎｇ，ＺｈａｏＬｉｈｕａ，ＨｕＷａｎｇｙｕ（王玲玲）（赵立华）（胡望宇））ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＨｕｎａｎＵｎ...

简介：研究1Cr17Ni2不锈钢中不同δ铁素体相含量变化分别在FeCl3溶液和HNO3＋HF溶液中的耐腐蚀行为。通过腐蚀失重率计算及光学金相显微镜、扫描电子显微镜的观察发现：在FeCl3溶液中,δ铁素体的存在减弱了1Cr17Ni2不锈钢的耐腐蚀性能,δ铁素体是优选腐蚀相;而在HNO3＋HF溶液中,δ铁素体的存在增强1Cr17Ni2不锈钢的耐腐蚀性能,优选腐蚀相则变成了回火索氏体。通过表面腐蚀形貌表征可以实现反推其受到腐蚀介质环境的性质,为1Cr17Ni2不锈钢腐蚀失效与预防提供可行的方法和依据。

简介：近日上市公司——“北矿磁材”股票价格连续飙涨的原因终于找到了。已拥有8家上市公司的大型央企中国五矿集团，继去年大规模收编数家央企和地方企业之后，马不停蹄地又选定了这家上市公司的控股股东——北京矿冶研究总院。

简介：TiO2nanoparticleswithdifferentphasesarepreparedbyhydrolysisoftitaniumtetrabutoxideinthepresenceofHCl.ThecompositionandmicrostructureoftheresultingsamplesarestudiedbyXRDandTEM.TheseresultsshowthattherangeofparticlesizeofTiO2isfrom20to30nm.ThemechanismofTiO2photocatalysisreactionhasbeendiscussedextensively.PhotocatalyticactivitiesofnanometerTiO2arealsoevaluatedbydegradationofthecrystalvioletsolution.ExperimentalresultsindicatethatthesynergisticactionofH2O2andultrasonicwavegreatlyenhancesphoto-catalyticreactionofTiO2.

简介：Iron(Ⅲ)-dopednanostructureTiO2-coatedSiO2(TiO2/SiO2)particleswerepreparedusingthelayer-by-layeras-semblytechniqueandtheirphotocatalyticpropertywasstudied.TiO2colloidsweresynthesizedemployingthesol-gelmethodwithTiCl4asaprecursor.ThesampleswerecharacterizedbyFouriertransforminfraredspectroscopy(FTIR),SEM,EDS,XPS,andXRD.TheexperimentalresultsshowthatTiO2nanopowdersonthesurfaceofSiO2particlesarewelldistributed,theamountofTiO2isincreasedwiththeaddingofcoatinglayers,thepureanatase-TiO2coatinglayersaresynthesizedat500°C,andthephotocatalyticactivityofFe3+-dopedTiO2/SiO2ishigherthanthatofundopedTiO2/SiO2.

简介：Nb-24Ti-18Si-2Al-2Hf-4CrandNb-24Ti-18Si-2Al-2Hf-8Cralloyswerepreparedbyarcmeltinginawater-cooledcrucibleunderargonatmosphere.Microstructuralcharacteristicsandoxidationresistanceofthealloysat1250℃wereinvestigated.Theresultsshowthat,whentheCrcontentis4at%,themicrostructuresconsistof(Nb,Ti)_(ss)andNb_5Si_3;asCrcontentincreasesto8at%,C14LavesphaseCr_2Nbisformed.Theisothermaloxidationtestsshowthattheoxidationkineticsofthetwoalloysfollowsimilarfeatures.Theweightgainsofthetwoalloysafteroxidationat1250℃for100hare235.61and198.50mg·cm~(-2),respectively.Duringoxidation,SiO_2,TiO_2,Nb_2O_5andCrNbO_4areformedatfirst.Then,Ti_2Nb_(10)O_(29)isformedafteroxidationfor20minandbeginstochangeintoTiNb_2O_7astheoxidationproceeds.SiO_2isformedassolidstateatfirstbutlaterevolvesintoglassystatetoimprovethecohesionofthescale.Afteroxidationfor100h,oxidationproductsconsistofSiO_2,TiNb_2O_7,Nb_2O_5andCrNbO_4.

简介：介绍一种金属/合金的生产方法,用于恒电流和恒电位条件下由混合硫化物(Cu2S,NiS)生产Cu-Ni合金,称为直接电化学还原(DER)。研究槽电压和槽电流等工艺参数对还原得到的化合物组成的影响,以生产工业所需的CuNi10,CuNi20和CuNi30等合金。在1200°C下采用循环伏安法(CV)考察Cu2S和NiS在CaCl2熔体中的电化学行为。根据CV研究结果,Cu2S的阴极还原是一步完成的,即Cu2S?Cu;NiS的阴极还原则分两步进行,即NiS?Ni3S2?Ni。恒电流研究表明,在10A电流下电解15min,可制备出最高硫含量为320×10-6的高纯CuNi10合金。扫描电子显微镜以及能量色散X射线能谱和光学发射光谱(OES)测试结果表明,在2.5V电压下直接电化学还原15min,可制备出杂质含量低(即硫含量小于60×10-6)的所选成分的Cu-Ni合金。

简介：本文采用磁粉、X射线、CT和超声等无损检测和金相分析等方法对40CrNi2Si2,MoVA钢制零件的磁痕显示进行了系统分析。研究认为，40CrNi2Si2MoVA钢制零件的磁痕显示为显微成分沿变形方向偏析导致的马氏体转变点Ms差异所致。显微成分偏析是钢锭结晶过程中不可避免的，但可通过优化熔炼工艺参数降低显微偏析的程度。本文还分析了四种磁痕显示的类型及其判别方法。

简介：Themetal-organicchemicalvapordeposition(MOCVD)techniqueisapromisingprocessforhigh-temperaturesuperconductorYBa2Cu3O7-δ(YBCO)preparation.Inthistechnique,itisachallengetoobtainbariumprecursorswithhighvolatility.Inaddition,thepurity,evaporationcharacteristics,andthermostabilityofadoptedprecursorsinwholeprocesswilldecidethequalityandreproducibleresultsofYBCOfilm.Inthepresentreport,bis(2,2,6,6-tetramethyl-3,5-heptanedionato)barium(Ⅱ)(Ba(TMHD)2)wassynthesized,anditsstructurewasidentifiedbyFTIR,1HNMR,13CNMR,andESI-MSspectroscopy.Subsequently,thethermalpropertiesandthekineticsofdecompositionweresystematicallyinvestigatedbynonisothermalthermogravimetricanalysismethods.BasedontheaverageapparentactivationenergyevaluatedbytheOzawa,Kissinger,andFriedmanmethods,thevolatilizationprocesswasdiscussed,andallresultsshowthatBa(TMHD)2isunstableandhighlysensitivetothechangeoftemperatureduringthewholeevaporationprocess.Therefore,itisveryimportanttochoosesuitablevolatilizationtechnologyandconditionsforavoidingBa(TMHD)2break-down(orthermalaging)duringMOCVDprocess.Subsequently,thepossibleconversionfunctionisestimatedthroughtheCoats-Redfernmethodtocharacterizetheevaporationpatternsandfollowsaphaseboundaryreactionmechanismbythecontractingsurfaceequationwithaverageactivationenergyof118.7kJ.mol-1.

简介：在这份报纸，纺纱冰上的无磁性的Y离子的冲淡效果加重Dy2Ti2O7由红外线并且拉曼系列和磁化大小被调查。与温度弄软减少的异常声子在父母被发现并且冲淡除了之外，做的混合物，和Y能放松弄软声子233附近的红外模式?厘米<啜class=“a-plus-plus”>显示在纺纱冰材料联合的强壮的phononphonon的1,。当冲淡的水平不很高时，磁化大小表明无磁性的杂质严重地不处于扎根的状态影响纺纱冰规则。然而，大量冲淡提高混乱并且因为集体旋转扭动簇不再是可得到的，打破纺纱冰状态。

简介：起落架40CrNi2Si2MoVA钢螺桩在安装一段时间后发生了断裂。为确定螺桩断裂的原因，对断裂螺桩断口宏微观形貌、断裂螺桩及对比件的氢含量、材料的性能以及表面损伤等因素进行了检查，并对电镀工艺进行了评定。结果表明，裂纹主要起源于第一螺纹根部的机械损伤部位，源区以沿晶断裂特征为主，断裂件含氢量较高。综合分析认为。螺桩断裂性质为氢致延迟断裂，表面机械损伤对氢吸收和扩散的促进作用和40CrNi2Si2MoVA钢材料高强度所致的高氢脆敏感性是导致断裂的主要原因。

简介：InordertoobtainultrafineNd-Fe-Bpowder,aspray-driedprecursorwastreatedbyreduction-diffusion(R/D)process.And,unliketheconventionalR/Dprocess,calciumreductionthatisacrucialstepfortheformationofNd2Fe14BwasperformedwithoutconglomeratingtheprecursorwithCapowder.Byadoptingthismodifiedprocess,itispossibletosynthesizethehardmagneticNd2Fe14Batthereactiontemperatureaslowas850℃.TheaveragesizeofNd2Fe14Bparticlesthatareuniformlydistributedintheoptimallytreatedpowderwas＜＜1μm.MostNd2Fe14BparticleswereenclosedwiththinlayersofNd-richphase.TypicalmagneticpropertiesofsuchpowderwithouteliminatingimpurityCaOwereiHc=～5.9kOe,Br=～5.5kG,and(BH)max=～6MGOe.

简介：通过金相、透射电镜、扫描电镜、超声无损检测和结合强度测试,研究7B52叠层铝合金热轧复合的结合界面。结果表明：轧制复合能够使界面获得冶金结合。TEM分析和拉伸试验表明：7B52叠层铝合金板材是由高强度硬层材料和高韧性软层材料复合而成。然而,超声无损检测和SEM分析表明：结合界面处的缺陷（如厚氧化层、酸洗残留物、空气、油渍和粗大粒子等）不利于界面结合强度。总之,轧制复合工艺适用于7B52叠层铝合金板材,且应该严格控制缺陷的数量和尺寸。先进的单层板表面处理技术有利于进一步提升结合质量。

简介：通过基于密度泛函理论的第一性原理计算方法,对MgCu2,Mg2Ca和MgZn2的力学性能和电子结构进行计算,计算所得晶格参数与实验值和文献值相吻合。合金形成热和结合能的计算结果表明,MgCu2具有最强的合金形成能力和结构稳定性。计算了MgCu2,Mg2Ca和MgZn2的弹性常数,推导了体模量、剪切模量、弹性模量和泊松比。结果表明,MgCu2、Mg2Ca和MgZn2均为延性相,MgCu2的刚度最大,MgZn2的塑性最好。通过对结合能和弹性常数的计算,预测了MgCu2、Mg2Ca和MgZn2的熔点。通过对态密度（DOS）、Mulliken布居数、电子占据数和差分电荷密度的计算,分析了MgCu2、Mg2Ca和MgZn2的结构稳定性和力学性能机制。最后,计算和讨论了3种金属间化合物的Debye温度。