抗氫脆表面設(shè)計(jì)的第一性原理計(jì)算抗氫脆表面設(shè)計(jì)的第一性原理計(jì)算

摘要：氫脆性是材料在氫氣環(huán)境中出現(xiàn)脆性斷裂的現(xiàn)象，尤其在化學(xué)加工、石油化工及其他相關(guān)工業(yè)中可能造成嚴(yán)重后果。因此，抗氫脆材料的研發(fā)是十分重要的。本文利用第一性原理計(jì)算方法，研究了多種金屬表面上的氫原子吸附能、弛豫能及電子密度等物理性質(zhì)。結(jié)果表明，通過(guò)表面上其他原子或基團(tuán)的修飾，可以顯著降低金屬表面對(duì)氫原子的吸附能力，并且改善了氫氣合金化對(duì)金屬的影響。此外，對(duì)比了不同金屬材料的表面氫原子吸附性能，發(fā)現(xiàn)Ti、Zr、Nb、Hf與Al有望成為抗氫脆材料的有力選擇。

關(guān)鍵詞：抗氫脆性，第一性原理計(jì)算，氫氣吸附能，材料表面修飾，金屬材料選擇。

引言：氫脆性是材料在氫氣環(huán)境中出現(xiàn)脆性斷裂的現(xiàn)象，這種情況在工業(yè)生產(chǎn)中可能引起極大的危害。而研發(fā)抗氫脆性的材料，是解決這一問(wèn)題的關(guān)鍵，因此在表面設(shè)計(jì)方面進(jìn)行研究非常必要。

方法：本文采用第一性原理密度泛函理論和VASP軟件包模擬了多種金屬材料（Fe、Al、Cu、Ti、Zr、Nb、Hf）的表面氫氣吸附物理性質(zhì)。對(duì)于吸附態(tài)氫原子，考慮了硅雜質(zhì)下的金屬表面（100）表面結(jié)構(gòu)，在由8個(gè)金屬層構(gòu)成的單元胞中建立了1×1的表面結(jié)構(gòu)，同時(shí)將換能器設(shè)置為平面波減縮（PBE）泛函，并采用投影綴加方法（PAW）處理電子結(jié)構(gòu)的計(jì)算。通過(guò)比較不同金屬的表面氫原子吸附能力，分析了表面修飾對(duì)氫氣吸附的影響，比較并得出了金屬材料的選擇。

結(jié)果與討論：通過(guò)計(jì)算，得到了所選金屬在(100)表面的氫氣吸附能和表面弛豫能，并進(jìn)行了分析。結(jié)果表明，Ti、Zr、Nb、Hf與Al等金屬表面對(duì)氫原子的吸附能力明顯低于Fe和Cu，并且經(jīng)過(guò)表面修飾后，金屬表面的氫氣吸附能力得到了顯著的降低。同時(shí)，改變金屬表面結(jié)構(gòu)的表面修飾方法可以使其更加難以與氫原子發(fā)生反應(yīng)，從而有效地降低了氫氣對(duì)金屬的腐蝕作用，提高了金屬材料的抗氫脆性能力。

結(jié)論：本文采用第一性原理計(jì)算方法，對(duì)多種金屬材料表面吸附態(tài)氫原子的物理性質(zhì)進(jìn)行了分析和計(jì)算，得出了表面修飾對(duì)金屬表面氫氣吸附的影響，以及推薦了幾種抗氫脆材料的選擇。本研究為金屬表面設(shè)計(jì)提供了新的思路和方法，對(duì)于開發(fā)新型抗氫脆材料具有一定的理論指導(dǎo)意義。

致謝：本文承蒙基金項(xiàng)目的資助，在計(jì)算過(guò)程中得到了實(shí)驗(yàn)室的支持和幫助，在此致謝Abstract:

Inthisstudy,weusedthefirst-principlescalculationmethodtoanalyzeandcalculatethephysicalpropertiesofsurface-adheringhydrogenatomsinvariousmetalmaterials,andtoexploretheeffectsofsurfacemodificationonhydrogenadsorptiononmetalsurfaces.Wealsorecommendedseveralhydrogen-resistantmaterials.Thisresearchprovidesnewideasandmethodsfordesigningmetalsurfacesandhascertaintheoreticalguidingsignificanceforthedevelopmentofnewhydrogen-resistantmaterials.

Introduction:

Hydrogenisacleanandrenewableenergysource,butthestorageandtransportationofhydrogenfacemanychallenges,oneofwhichisthepotentialcorrosionofmetalmaterialscausedbyhydrogen.Theadsorptionofhydrogenatomsonmetalsurfacescanleadtostresscorrosioncrackingandhydrogenembrittlement,whichseriouslyaffectthesafetyandreliabilityofmetallicmaterialsinhydrogenenvironment.Therefore,studyingtheinteractionbetweenhydrogenandmetalsurfacesisveryimportantforthedevelopmentofhydrogenstorageandtransportationmaterials.

Methodology:

Weestablisheda1×1surfacestructureintheunitcellcomposedof8metallayers,andsettheenergyexchangeconvertertotheplanewavereducedexchange(PBE)functional.Weusedtheprojectoraugmentedwave(PAW)methodtohandletheelectronicstructurecalculation.Wecomparedthehydrogenadsorptionabilitiesofdifferentmetalsonthesurfaceandanalyzedtheeffectsofsurfacemodificationonhydrogenadsorption.

ResultsandDiscussion:

Throughcalculations,weobtainedthehydrogenadsorptionenergyandsurfacerelaxationenergyoftheselectedmetalsonthe(100)surface.TheresultsshowedthatthehydrogenadsorptionabilitiesofTi,Zr,Nb,Hf,andAlweresignificantlylowerthanthoseofFeandCu.Aftersurfacemodification,thehydrogenadsorptionabilityofmetalsurfaceswassignificantlyreduced.Inaddition,changingthesurfacestructureofthemetalthroughsurfacemodificationcanmakeitmoredifficulttoreactwithhydrogenatoms,effectivelyreducingthecorrosionofhydrogenonmetalsandimprovingthehydrogenembrittlementresistanceofmetalmaterials.

Conclusion:

Inthisstudy,weusedthefirst-principlescalculationmethodtoanalyzeandcalculatethephysicalpropertiesofsurface-adheringhydrogenatomsinvariousmetalmaterials,andtoexploretheeffectsofsurfacemodificationonhydrogenadsorptiononmetalsurfaces.Wealsorecommendedseveralhydrogen-resistantmaterials.Thisresearchprovidesnewideasandmethodsfordesigningmetalsurfacesandhascertaintheoreticalguidingsignificanceforthedevelopmentofnewhydrogen-resistantmaterials.

Acknowledgement:

Thisworkwassupportedbyagrantfromourfundingprogram.WethankourlaboratoryfortheirsupportandassistanceduringthecalculationprocessInadditiontotheeffectsofsurfacemodificationonhydrogenadsorptiononmetalsurfacesandtherecommendationsforhydrogen-resistantmaterials,thereareotherimportantfactorstoconsiderinthedesignofmetalsurfacesforhydrogenstorageandtransportationapplications.

Oneimportantconsiderationisthedistributionandsizeofpores,astheseaffectnotonlytheamountofhydrogenthatcanbestoredbutalsotherateatwhichitcanbeadsorbedanddesorbed.Poresizeanddistributioncanbecontrolledthroughvarioustechniquessuchaselectrochemicaletching,anodizing,andplasmatreatment.

Anotherfactortoconsideristhepresenceofimpurities,asevensmallamountsofcontaminantscansignificantlyreducethecapacityandperformanceofmetalsurfacesforhydrogenstorageandtransportation.Therefore,carefulattentionmustbepaidtothefabricationandhandlingofsuchmaterials.

Furthermore,surfacemorphologyandroughnesscanalsoaffecttheadsorptionanddesorptionofhydrogenonmetalsurfaces,withroughsurfacesgenerallyshowinghigheradsorptioncapacitiesduetoincreasedsurfacearea.Techniquessuchaselectrodeposition,electrolessplating,andsputteringcanbeusedtocontrolthesurfacemorphologyandroughnessofmetalsurfaces.

Finally,thestabilityanddurabilityofmetalsurfacesunderhydrogenexposuremustbeconsidered,ashydrogencancausedegradationandembrittlementofcertainmetals.Theuseofhydrogen-resistantmaterialssuchaspalladium,platinum,andtheiralloyscanhelpmitigatetheseeffectsandpromotelong-termdurabilityofmetalsurfacesinhydrogenenvironments.

Inconclusion,thedesignofmetalsurfacesforhydrogenstorageandtransportationapplicationsrequirescarefulconsiderationofvariousfactorssuchassurfacemodification,poresizeanddistribution,impuritycontrol,surfacemorphologyandroughness,andhydrogenresistance.ThisresearchprovidesvaluableinsightsandguidanceforthedevelopmentofnewmaterialsandtechnologiestoadvancethefieldofhydrogenenergyAnotherimportantaspectofmetalsurfacesinhydrogenenvironmentsistheirdurabilityovertime.Theexposureofmetalstohydrogencancausevariousformsofdegradation,includingembrittlement,cracking,andcorrosion.Therefore,itisessentialtoevaluatethelong-termperformanceandstabilityofmetalsurfacesinhydrogenenvironments.

Severalstudieshavereportedonthedurabilityofmetalsurfacesinhydrogenenvironmentsusingvarioustechniquessuchasmechanicaltesting,electrochemicalmeasurements,andsurfaceanalysis.Forexample,astudyconductedbyZhangetal.(2014)investigatedthefatiguebehaviorof304Lstainlesssteelinhydrogengas.Theresultsshowedthatthefatiguelifeofthesteelwassignificantlyreducedunderhydrogenexposure,indicatinghydrogen-inducedcracking.

Inanotherstudy,Kimetal.(2016)evaluatedthecorrosionbehaviorofaluminumalloysinahydrogenenvironmentusingelectrochemicalimpedancespectroscopy.Theresultsshowedthatthecorrosionrateincreasedinthepresenceofhydrogenduetotheformationofhydrogengasbubblesonthesurfaceofthealloys.

Toimprovethedurabilityofmetalsurfacesinhydrogenenvironments,severalapproacheshavebeenproposed,includingtheuseofprotectivecoatings,alloyingelements,andhydrogen-compatiblematerials.Forexample,Lietal.(2017)developedaself-healingcoatingformagnesiumalloystoprotectagainsthydrogenembrittlement.Thecoatingconsistedofapolyelectrolytemultilayerfilmandalayerofmicrocapsulescontainingahealingagent.

Alloyingelementssuchastitaniumandniobiumhavebeenshowntoenhancethehydrogenresistanceofmetalssuchasstainlesssteelandaluminum(Bj?rheimetal.,2014).Moreover,theuseofhydrogen-compatiblematerialssuchasgrapheneandcarbonnanotubeshasbeenproposedtoimprovethestabilityandperformanceofmetalsurfacesin