镓物理化学性质调研.ppt

镓 基本信息 物理化学特性 银白色金属 在30 时变为发光液体 冷却至0 而不固化 在干燥空气中稳定 在潮湿空气中失去光泽 生成及少量氧化物 与碱反应放出氢气 能被冷浓盐酸浸蚀 对热硝酸钝性 高温时能与多数非金属反应 溶于酸和碱 微溶于汞 不溶于水 研究表明 镓在高温下对工程材料具有较强的腐蚀性 如300 400 或更高温度下对不锈钢的腐蚀性 室温下的腐蚀性通常可以忽略 低温下 30 可与铜缓慢发生反应 进而导致铜表面出现凹陷 实验验证 镓一般不与塑料 聚乙烯 聚丙烯 聚苯乙烯 PMMA 发生反应 即使温度升高至足以使上述塑料软化或熔化 镓不溶于水 因此经皮肤镓不容易被吸收 眼睛直接接触或吸入镓粉末会导致疼痛 豚鼠皮下注入镓金属或合金导致骨疽 对猫和鼠而言 胃对硫酸镓及硝酸钾的大剂量吸收会导致轻微中毒 人应尽量避免在三氧化二镓的环境下长期工作 一旦液态钾金属溅落至工作场所 如地板 先确认是否有导电可能 如果没有则立刻用冷水冲洗直至镓凝固 然后再做收集保存 为防止镓被人手的油污染 手套是必须的 6063Aluminum Alloy 5hoursofcorrosionunder120 CT2Copper AlloyAnodicColoring6063Aluminum Alloy1Cr18Ni9StainlessSteel 30daysatthetemperatureof60 0 5 C Corrosiondevelopmentbetweenliquidgalliumandfourtypicalmetalsubstrates Testobjectandcondition Morphologycomparisonofcorrodedsurfaceofthe6063Aluminum Alloy a andoftheT2Copper Alloy b Corrosiondevelopmentsbetweenthe6063Aluminum Alloyandliquidgallium anodisturbanceisexertedongalliumball bsmalldisturbanceisexertedongalliumball EDSanalysis 6063Aluminum Alloy T2Copper Alloy 1Cr18Ni9StainlessSteel AnodicColoring6063Aluminum Alloy Conclusion 6063Aluminum Alloy Liquidgalliumhasintensecorrosionreactionwithit andthecorrosionproductisloose promotingtheinfiltrationofgalliumintothecorrosionproducttoformcorrosiondiffusionareawithuniformgalliumconcentration Thecorrosionproductisalsooflowintensity Thus the6063Aluminum Alloycannotbeusedasthestructurematerialforaliquidmetalcoolingsystem T2copper Liquidgalliumnotonlycausesuniformcorrosionprocesstothesurfaceofit butalsohasgoodcompatibilitywiththecorrosionlayerandcanformgalliumcoveredareaonthecorrodedsurface ThecorrosionresistanceleveloftheT2Copper Alloyisbetweengrade6and7 whichbelongstoaslightlyhighgrade ButtheT2Copper Alloyisinappropriatetobeusedasstructuralmaterialofaliquidmetalcoolingsystemforthedynamiccorrosionprocesswillcausegreatdamagetoitssurface X AnodicColoring6063Aluminum Ithasverystrongcorrosionresistance However intheflowingliquidmetalcoolingsystem thescouringeffectthatliquidmetaloflargedensitycausestotheoxidelayeronthesurfacemustbeconsidered Meanwhile theoxidelayercannotbescratchedsoastoavoidgalliuminfiltration Whatismore thesystemthermalresistancewillincreasebecauseofthethinoxidelayer Thus theAnodicColoring6063Aluminum Alloycanbeusedasstructuralmaterialofaliquidmetalcoolingsystemonlyaftercertaingoodsurfacetreatments Andtheincreasedthermalresistanceshouldbecorrectlyevaluatedforpracticaldesignofaliquidmetalcoolingsystem 1Cr18Ni9StainlessSteel Itshowsintegralcorrosionresistance highsurfacestrengthandstrongresistancetoscouring Theonlyshortcomingliesinitsrelativelylowthermalconductivity Comprehensivelyconsideringtheeconomyandpracticality the1Cr18Ni9stainlesssteelisthebeststructuralmaterialamongthetestedfourspecimensforaliquidmetalcoolingsystem CorrosionresistanceofstructuralmaterialstoGa2Oat1000 Testobjectandcondition 2h 20h Conclusion ThepoorperformanceofAlloy625at1000CisconsistentwithitspoorresistancetoGaatlowertemperatures 400 ThepoorperformanceofStellite6islikelyassociatedwithboththehighsolubilityofGainCo whichisaprimarycomponentofthisalloy andwithitshighCrcontent CrappearstoplayasignificantroleincorrosiveattackofboththesealloysbyGa2O ThisselectionoftheCo richphaseasthepreferreddiffusionpathforGapenetrationintoStellite6isconsistentwiththehighdiffusivityandsolubilityofGainCo AsforW Cu Nialloy GaisseentopenetratedeeplybeyondthereactionzoneatthesurfacebymeansoftheCu Niphase ThisresultisconsistentwiththepenetrationofGaintoCuinterphaseregions CuandNiappeartohavediffusedfromthebasemetaltointeractwithGaincreatingthereactionzoneatthesamplesurface AsforHigh purityW neithersignificantscalenorareactionzoneareobservableatthesurfaceofthesample AsforSiliconcarbide neitherascalenorareactionzoneareobservedatthesurfaceofthesample CompatibilityofITERCandidateMaterialswithStaticGallium Testobjectandcondition Type316SS 不锈钢 Inconel625 铬镍铁合金 Nb 5Mo 1ZralloyNickel270 99 995wt Ni ArmcoironPurechromium At300and400 Cforupto3000h Conclusion Corrosionratesforthealloysarelowerthanthoseforthepuremetals Theiron basedType316SSexhibitmorecorrosionthanthenickel basedInconel625 At400 thecorrosionrateofType316SSisnearlyoneorderofmagnitudegreaterthanthatofInconel625 Type316SSspecimensexposedat400 Cexhibitedsignificantcorrosionandformationofathick porousreactionlayer Althoughsignificantcorrosionoccurred thespecimenswerenotpreferentiallyattackedalongthegrainboundaries Exposuretogalliumat400 Cforextendedtesttimes 1000h ledtoseparationofthespecimenatthebend resultinginacceleratedcorrosionatthesampleends XRDanalysisconfirmedthatthereactionlayeronType316SSconsistedprimarilyofFeGa3andgallium withsomeCrGa4intheregionnexttothesteelsurface Inconel625specimensshowedsignificantcorrosionat400 Candlittleornocorrosionat300 C TheInconel625specimensexposedat300 Cexhibitednoreactionlayergrowth however themetalsurfacewasetchedbytheliquidmetal At400 metallossandreactionlayergrowthwasevident Layergrowthoccurredevenlyontheexposedsurface withoutinter granularattack Therewasnodistinctionbetweenattackofcold workedandnoncold workedregions ThereactionlayercontainedCrGa4andgalliumacrosstheentirethickness XRDalsoidentifiedthepresenceofthe X phaseobservedintheNickel270specimen TheNb 5Mo lZralloyshowednomeasurablecorrosionat300or400 C TheNb 5Mo 1Zralloyshowednomeasurablecorrosionat300or4OO C althoughthereappearedtobesignificantattackofthecold workedregion Thesurfaceofthespecimensafterexposurewassmooth withverylittleformationofinter metalliccompoundAn 0 5 mm thickironspecimenreactedcompletelywithin24h 400 Armcoironexposedtogalliumat300 CdevelopedaveryporousandthickreactionlayerthatwasidentifiedbyX raydiffraction XRD analysisasFeGa3 withgalliummetalpresentinthepores SimilarcorrosionbehaviorwasobservedforNickel270 inwhichthereactionlayerprimarilyconsistedofNi2Ga3andcontainedsmallamountsofNiGa4intheregionincontactwithgallium An 0 3 mm thickchromiumspecimendisintegratedwithin100h 400 Asomewhatdifferentbehaviorwasobservedforchromiummetal thespecimendisintegratedintosmallcrystals analysisshowedthecrystalstobeCrGa4 indicatingthatthemechanismforcorrosionofchromiumisbasicallythesameasthatfornickeloriron ThedifferenceisthattheCrGa4 phaseinequilibriumwiththesaturatedsol