简介:Anewhardfacingprocess,reactivebrazecoatingprocess(RBCC)wasstudied,and(TiC+Cr3C2)/FecompositecoatingswerepreparedbyRBCCusingcarbon,Cr3C2,iron,ferrochromiumandtitaniumpowderastherawmaterialsinvacuumbrazefurnace.TheresultsshowthatTiCisin-situsynthesizedinthecoatings.ThemethodsofintroducingCr3C2havegreateffectsonthedistributionofTiC.AddingCr3C2directlytotherawmaterialsforcoatings,fineTiCparticlesaggregateintodiscoidsparalleltothecoatingsurface,whereas,in-situsynthesizingCr3C2incoatings,theaggregationsofTiCarelumpish.Duringbrazecoating,Cr3C2particlesdirectlyaddeddissolveandprecipitatetobecomeneedle-shaped.Thecoatingshaveanevenandsmoothsurfaceandarecombinedwiththeirmildsteelsubstratesbyametallurgicalbonding.
简介:Laserblankweldingisbecomingmoreandmoreimportantintheautomotiveindustryandthequalityoftheweldiscriticalforasuccessfulapplication.Afullyautomatedsolutionisrequiredtoinspectthequalityoftheblanks.ThispaperpresentsavisioninspectionsystemwithaCMOScamerawhichusesART2networktoinspectthedefectson-linetoobtainthegeometryandthequalityoftheweldseam.TheneuralnetworkART2hasthecapabilityofself-learningfromtheenvironment.Itcandistinguishthedefectsthathavebeenlearnedbeforeandgivenewoutputsfornewdefects.SoART2networkissuitableforweldqualityinspectioninlaserblankwelding.Additionally,aCO_2laserisusedfortheblankbutt-welding.
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:介绍了刚-挠结合型印制电路板封装技术的原理、做法和在空间技术中应用的重要意义。
简介:本文介绍了一种新开发的不含卤和磷等阻燃添加剂的高阻燃性玻纤-环氧树脂覆铜板。这种覆铜板主要是由自熄性环氧树脂化合物(酚基芳烷烃类)、不可燃气体发生剂(氨基-三嗪-诺瓦拉克型固化剂,ATN型固化剂)、无机填料如炭化促进剂(钼酸锌滑石粉,ZMT)及一定量的无害金属氢氧化物如氢氧化铝(ATH)等组成。这种覆铜板有良好的阻燃性,并且耐浸焊性、耐潮湿性、电性能优良,加工性能也很好,这些好的性能使这种新型板材足可以代替现在广泛应用的FR-4印制电路基材。在覆铜板制造中同时应用ATN型固化剂和ZMT,与自熄性环氧树脂化合物、ATH等协同作用,大大地提高了阻燃性能;减少了ATH的用量,有利于改进耐浸焊性、耐潮湿性和电性能。