学科分类
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500 个结果
  • 简介:采用Al-5Ti-B变质剂对过共晶Al-18Si合金进行反向变质处理,用光学显微镜观察合金的组织与形貌,研究变质剂加入量、变质温度和冷却速度对初晶硅的尺寸、形态和面积分数以及共晶组织的影响。研究表明:当Al-5Ti-B加入量(质量分数)为0.3%时,变质处理后Al-18Si合金中的初晶硅和共晶硅尺寸明显减小,初晶硅的面积分数减小;与其相比,变质剂加入量增加到0.6%时,初晶硅尺寸变化不明显,但共晶硅进一步细化;随冷却速率降低,变质处理后Al-18Si合金中初晶硅相的数量减少,但Si颗粒尺寸明显增大,并且共晶硅细化;与Al-18Si合金在720℃变质相比,该合金在780℃变质处理时,初晶硅的尺寸增大,但初晶硅的面积分数显著减小;合金在850℃变质处理后初晶硅的尺寸、面积分数都比720℃变质处理后明显减小;随变质温度升高,Al-Si合金中的共晶硅明显细化。

  • 标签: 过共晶铝硅合金 初晶硅 共晶硅 反向变质 变质机理
  • 简介:国际镍业研究组织(INSG)11月17日表示,全球镍市9月供应过剩8,300吨,过剩规模低于前月修正后的8,400吨。INSG称,全球初级镍产量9月总计为160,300吨,高于152,000吨的消费量。

  • 标签: 供应 研究组织 消费量
  • 简介:Pr2Fe14B-La2Fe14B系统被衍射(XRD),微分扫描热量测定(DSC)和扫描电子显微镜学(SEM)与精力装备了的X光检查粉末调查散X光检查光谱学(版本)。水晶结构参数被完整侧面的Rietveld精炼决定。结果揭示了那所有合金(Pr1-xLax)2Fe14B使Nd2Fe14有空格组P42/mnm的B类型结构并且形成了连续固体在x=0.0之间的解决方案并且1.0。格子参数一,c,单位房间体积V和c/a比率与La集中线性地增加了。由thermogravimetry分析决定了,居里温度(TC),阶段转变温度和融化的温度(Pr1-xLax)2Fe14B在La内容之上线性地减少了。基于DSC大小和X光检查粉末衍射考试的结果,Pr2Fe14B-La2Fe14B系统被建立。

  • 标签: 水晶结构 格子参数 居里温度 热分析 稀土元素
  • 简介:TheNd60Fe20Al8Co10B2alloywaspreparedbysuctioncastingofthemoltenalloyintoacoppermoldunderargonatmosphere.Themicro-structuralandmagneticpropertychangesintheNd60Fe20Al8Co10B2alloyduringcrystallizationwereinvestigatedbyX-raydiffraction(XRD),differentialscanningcalorimetry(DSC),scanningelectronmicroscope(SEM)andthevibratingsamplemagnetometer(VSM).TheprecipitationandNd-richandFe-richphaseshavenosignificanteffectontheintrinsiccoercitityforNd60Fe20Al8Co10B2alloyannealedbelow723K.However,thegrowthofFe-richphasedecreasesthesaturatemagnetizationandremanenceofthealloy.Thehardmagneticbehaviorisdisappearedwhenthealloyisfullycrystallized.

  • 标签: Nd60Fe20Al8Co10B2 铸造合金 结构 磁性能 XRD DSC
  • 简介:La15Fe77B8hydrogenstoragealloyswerepreparedusingavacuuminduction-quenchingfurnace.TheresultsofX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)suggestedthatLa15–xSmxFe2Ni76Mn5B2(x=0,2,4,6)alloyshadmultiphasestructureincludingthemainLaNi5phase,La3Ni13B2phaseand(Fe,Ni)phase.WiththeincreasingsubstitutionofSmforLa,themainphasestructureofalloysdidnotchange,whiletheunitcellvolumesdecreased,thecyclestabilitywasimprovedandthemaximumdischargecapacitydecreased,butthelowtemperaturemaximumdischargecapacityofthesamesubstitutionalloywasgraduallyapproachingthemaximumdischargecapacityatroomtemperature,whichshowedthatLa15Fe77B8hydrogenstoragealloysofthepartialsubstitutionofSmforLahadbetterlow-temperaturedischargeability(LTD).Forthesamesubstitutionalloys,self-dischargecharacteristicsandcyclestabilityatlowtemperaturewerebetterthanthatatroomtemperature.Furthermore,thehigh-ratedischargeability(HRD)andtheexchangecurrentdensityI0firstincreasedandthendecreasedwiththeincreasingofSmcontent,whereasthehydrogendiffusioncoefficientDinalloybulkdecreasedgradually,whichindicatedthatappropriatesubstitutionofSmforLaimprovedtheelectrochemicalkineticspropertiesofthealloys.TheHRDwasmainlydominatedbythecharge-transferrateonthealloysurface.

  • 标签: 贮氢合金 电化学性能 多相结构 高倍率放电性能 LANI5 扫描电子显微镜
  • 简介:分析证明了温度和时间对SWRH77B盘条性能的影响。选择一组人工时效的试验条件,进行人工与自然时效方法的对比试验,通过试验验证了可以通过选定条件下的人工时效试验来代替自然时效试验。

  • 标签: SWRH77B盘条 自然时效 人工时效
  • 简介:Magnetizationanddemagnetizationcurvesandhysteresisloopsapplieddifferentmagnetizing.fieldsinsinteredNd-Fe-BandNd-Dy-Fe-Bmagnetsfromthermallydemagnetizedanddcfield-demagnetizedstateswereinvestigatedattemperaturesofupto150℃.Thefirst-quadrantremagnetizationcurvesandthecurvesofcoerciveforces_MH_CversusrernagnetizingfietdsH_mfromdcfield-demagnetizedstateatroomtemperatureshowasteparoundmagnetizingfieldasabsolutevalueofthemaximumintrinsiccoercivity.Thestepsof_MH_C-H_mcurvesshiftedtolowerremagnetizingfieldsandtheshapesofmagnetizationcurveschangedfromsteptypetoprecipitoustypewhentemperaturewentupto100~150℃orafterthespecimenwasthermallydemagnetizedatatemperaturehigherthantheCurietemperature.Thesteepriseofkneecoereivitywithincreasingmagnetizingfieldisbehindthatof_MH_C.NotethatthemagnetichardeninginsinteredNd-Fe-Bmagnetsiscontrolledbypinningofdomainwalls.

  • 标签: MAGNETIZATION COERCIVITY thermally HYSTERESIS ABSOLUTE walls
  • 简介:YPO_4phosphorssingle-dopedwithSb~(3+)orGd~(3+)andco-dopedwithSb~(3+)andGd~(3+)werepreparedbyasolid-statereactionmethod.Thephasepurity,morphology,photoluminescenceexcitationandemissionpropertiesofthepreparedphosphorswereinvestigated.TheresultsshowedthatSb~(3+)couldsensitizeGd~(3+)intheco-dopedphosphorswhichmadethephosphorsexcitablebyshort-waveultraviolet(UV)atawavelengthbetween220and260nm.Under253.7nmexcitation,theco-dopedphosphorsY_(1–x–y)PO_4:Sb~(3+)x,Gd~(3+)yshowedstrongemissionofGd~(3+)atawavelengthof312nmwhoseintensitychangedwiththedopingconcentrationsofGd~(3+)andSb~(3+).TheoptimizedY_(0.77)PO_4:Sb~(3+)0.07,Gd~(3+)0.16phosphorshowedanintensitycomparabletocommercialLaPO_4:Cephosphor(UVB-315),makingitapotentialcandidateformercurylow-pressuredischargenarrow-bandUV-Bemittinglamps.

  • 标签: PHOSPHOR narrow ultraviolet doping excitation CALCINATION
  • 简介:本文对酒钢碳钢薄板厂7~#、8~#连铸机电磁流量计使用过程中存在问题进行详细的分析,制定具体的方案并实施改造,通过实施后效果数据的对比,达到了降低电磁流量计故障频率的改造效果,取得了一定的经济效益。

  • 标签: 连铸机 电磁流量计 接地 干扰
  • 简介:通过生产过程参数对比,查找宏观原因,并进行解剖,用SEM扫描电镜进行能谱分析,定性分析AAR-B车轮超声检测缺陷的原因,制定改进措施,使产品质量稳定。

  • 标签: AAR-B车轮 缺陷 超声检测 定性分析
  • 简介:利用扫描电子显微镜、能谱仪、光学显微镜及电子探针等对比分析了Q235B钢板拉伸试验后出现分层和不分层的两组试样,研究引起钢板拉伸分层的原因。试验结果表明:分层试样中心含有大量的MnS、Si02等夹杂,心部存在宽大的铁素体条带,是导致Q235B铜板出现拉伸分层现象的主要原因。根据分析结果提出改进措施以减少和消除此种缺陷。

  • 标签: Q235B铜拉伸分层夹杂带状
  • 简介:根据西沟矿露天采场穿孔的实际情况。对我矿所使用的KY-200B牙轮钻的钻杆从材质、转速、轴压方面进行改进,改进后的钻杆使用寿命延长一倍左右。我矿现有穿孔设备有:KQX-150潜孔钻2台、KQ-200潜孔钻、KY-200B牙轮钻2台,从而降低了钻孔的成本。

  • 标签: 45#无缝钢管 40Cr无缝钢管
  • 简介:美国宇航局在加州帕萨迪纳的喷气推进实验室研究成功了一种制造YBa2Cu3O7-α高温超导电缆(封装在金属套管内)的新方法。据称,这种方法成本较低,过程易于控制,且对各种前体材料有很强的适应能力。该法分4个步骤:生产具有化学(配)比的前体(Precursor)粉;将前体粉包封在金属套管内;用轧制的方法使前体粉固结;在液态锂金属浴槽内进行处理,使之转变成超导组

  • 标签: 粉末冶金 金属套管 高温超导电缆 锂金属 实验室研究 喷气推进
  • 简介:Eu2+andDy3+codoped(Ca,Sr)7(SiO3)6Cl2yellowphosphorsweresuccessfullysynthesizedbyself-fluxmethod.Thestructure,morphologyandphotoluminescencepropertieswereinvestigatedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andphotoluminescencespectra.Theas-preparedphosphorshowedabroademissionspectrumcenteredat550nmforEu2+single-dopedphosphor,whilelocatedat548–544nmfortheEu2+,Dy3+codopedsamplesunderexcitationat380nmlight.TheemissionintensitywasgreatlyimprovedwhenDy3+wasdopedintothe(Ca,Sr)7(SiO3)6Cl2:Eu2+system.Thecomposition-optimizedsamplewith3mol.%ofDy3+andconstant10mol.%ofEu2+exhibiteda220%PLenhancementcomparedtothephosphorwith10mol.%Eu2+single-doped.Meanwhile,itwasfoundthatthequantumefficiencyofphosphornamely(Ca,Sr)7(SiO3)6Cl2:3mol.%Dy3+,10mol.%Eu2+couldgetupto24.6%.Thesynthesizedyellow-emitting(Ca,Sr)7(SiO3)6Cl2:Dy3+,Eu2+isapromisingcandidateashigh-efficiencyyellowphosphorforNUV-excitedwhiteLEDs.

  • 标签: 镝掺杂 荧光粉 黄色 扫描电子显微镜
  • 简介:对304不锈钢2B板表面边鳞缺陷进行扫描电镜和能谱分析,并结合其整个生产工艺参数分析,得出铁素体当量高是导致边鳞缺陷发生的主要原因。根据上述原因提出了相应的改进建议。

  • 标签: 304不锈钢 2B板 边鳞
  • 简介:介绍了安钢烧结厂90/105m^2烧结系统B800链板运输机在生产中存在的问题,以及针对这些问题采取的技术改造措施和取得的效果。

  • 标签: 链板运输机 改造 效果 溜槽
  • 简介:Traditionally,austeniticstainlesssteels304and316havebeenemployedincoastalregionsasroofingmaterialsunfortunately,theyareexpensiveandnotfullyresistanttopittingcorrosionunderseverecoastalcorrosiveenvironment.AferriticstainlesssteelB445Rwasdeveloped.Comparedwithaustenitic316L,B445Ris①lesscostly;②uperiorcorrosionresistantwithminormaintenanceforlong-termservice;③insusceptibletothermaldistortionintheweldingseam.B445Rsheetshowsahigheryieldstrengthandlowertensilestrength,lowerelongationandlowerwork-hardeningthanaustenitic316L.Itcanbeeasilyfabricatedanddeformedjustlikeplaincarbonsteel.Afterbending180o,thereisnooccurrenceof'cracking'ornoticeable'orangepeel'.Theformabilityoftheweldingseamisalsosatisfactory.ThepittingpotentialofB445Ris650mV,largerthanthatof304and316L,asshowninFig.1.ThecorrosionrateofB445Rsubmergedin6%FeCl,solutionis0.3-0.56g/(m2?h-1),muchlowerthanthatof316L,asshowninFig.2.ThesuperiorpittingcorrosionresistanceofB445RcanbeascribedtosynergeticeffectofhigherCrandMo.Dull-finishedB445RsheetshavebeenemployedastheroofingmaterialsforGuangzhouAsianGamesArena,asshowninFig.3.About380tof1.0mmB445Rwithdullfinishwasusedforroofingpanels.About100tof0.8mmB445Rwithhairlineorfluororesinpaintfinishwasusedforsidewallpanels.Thecompositeroofbuild-up(fromuptobottom)includes:①shinglesofferriticstainlesssteelB445R;②Kalzip-typestandingseamofaustenitic304;③water-proofDFM;④structuralsteel;⑤75mmthickinsulation;⑥secondarypurlinof150mm×100mm×4.5mmofgalvaniziedQ235;⑦0.8mmthickprofiledeckofgalvaniziedQ235;⑧acousticinsulation.Theroofingshinglesorpanelswiththesamewidthbutdifferentlengthwereformedbybendingfoursidesandfixedtoa'L'shapereinforcingframesofstainlesssteelbyfasteners.The'L'frameswasconnectedtoribsofthestandingseambyacl

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  • 简介:介绍了鄂钢开发出口用英标GR460B螺纹钢的生产工艺和技术方案,并根据试制情况提出了切合实际的整改措施。

  • 标签: 英标GR460B 工艺改进