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:摘要针对2Cr13不锈钢零件焊接后镀硬铬时,出现焊缝表面镀铬层不完整,与零件表面镀层差异明显的问题,通过选取14种不同加工方式的工艺实验,对实验结果进行分析对比,筛选出最优的加工工艺方法,从实验结果推断出产生问题的理论缘由,解决实际问题,确保零件加工质量。
简介:由红外线的激光,表面reducibility和Cu-Cr的吸附力照耀建筑群能被改进,由于相片破碎和激光texturing的相互作用。由有约束力的精力系列和钻系列分析了,铬离子的原子价状态和铜离子分别地在放射以后是+3和+1,它仍然有reducibility释放电子。在对比与在红外线附近(NIR)1064nm并且中间红外线(米尔)在15W的一样的平均产量力量的10600nm激光,在Cu-Cr建筑群的减少的金属百分比显然与纳米在深度被区分开来到微米。在化学plating以后,平均涂层厚度和NIR样品的吝啬平方的偏差是11.61m并且0.30为铜层,和2.69m并且0.08为镍层。结果是比米尔样品的那些好一些的。
简介:Co(II)-salenwasencapsulatedinMIL-100(Cr)metalorganicframeworkby"shipinabottle"tosynthesizeanewelectrocatalyst,Cosalen@MIL-100(Cr).ThematerialwascharacterizedbyXRD,FT-IR,UV-VisandN2-adsorption.TheCosalen@MIL-100(Cr)modifiedglassycarbonelectrodeexhibitsawell-definedreductionpeakatthepotentialof–0.21Vtowardtheoxygenreductionreaction(ORR)bycyclicvoltammetry(CV)inpH=6.84phosphatebuffer.Almost400mVpositiveshiftofpotentialatCosalen@MIL-100(Cr)modifiedelectrodeforORRcomparedwiththatatbareglassycarbon,indicatesthatCosalen@MIL-100(Cr)possessesexcellentelectrocatalyticactivity.ThetransferrednumberofelectronsforORRwasdeterminedbychronocoulometry.TheresultsuggeststhattheintroductionofCo(II)-salencomplexintoMOFincreasestheelectrocatalyticactivityviaafour-electronreductionpathway.Furthermore,thiselectrocatalystexhibitsgoodstabilityandreproducibility.
简介:Wereportedabifunctionalmaterial,Cr-salenimplantedconjugatedmicroporouspolymer(Cr-CMP),whichisabletocaptureexcellentCO2amountsandhasaremarkablecatalyticactivitytowardsthecycloadditionreactionofCO2toepoxidesformingcycliccarbonatesatmildconditionswithoutadditionalsolvents.ThisheterogeneousCr-CMPcatalysthasasuperiorcatalyticactivitytoitsrelatedhomogeneouscatalystandcanbereusedmorethantentimeswithoutasignificantdecreaseincatalyticactivity.
简介:Chromiumacetylacetonateandbis(diphenylphosphino)isopropylaminewerecoordinatedinsituandsupportedonmethylaluminoxane-modifiedsilica.Thecatalyststructureandeffectsofreactiontemperature,reactionpressureandAl/Crmolarratioonethylenetetramerizationwereinvestigatedindetail.Chromiumwasuniformlyandfirmlyimmobilizedonthesupportandcouldnotbeleachedoffbymethylaluminoxane.Thesupportedcatalyst,uponbeingactivatedwithmethylaluminoxane,exhibitedcatalyticactivityof1.70×107g/(molCr·h)forethylenetetramerizationtoform1-octeneatareactiontemperaturesof80℃,apressureof2.0MPaandanAl/Crmolarratioof300.Thesupportedcatalystpresentedagoodtolerancetohightemperature.