Ua tsaug rau koj tuaj xyuas Nature.com.Qhov browser version koj siv tau txwv CSS kev txhawb nqa.Rau qhov kev paub zoo tshaj plaws, peb xav kom koj siv qhov browser tshiab (lossis lov tes taw Compatibility Hom hauv Internet Explorer).Nyob rau lub sijhawm no, txhawm rau ua kom muaj kev txhawb nqa txuas ntxiv, peb yuav ua rau lub xaib tsis muaj qauv thiab JavaScript.
Cov hlau tsis zoo siv dav siv thiab nws cov qauv wrought yog resistant rau corrosion nyob rau hauv ambient tej yam kev mob vim lub passivation txheej muaj xws li chromium oxide.Corrosion thiab yaig ntawm cov hlau yog ib txwm cuam tshuam nrog kev puas tsuaj ntawm cov khaubncaws sab nraud povtseg, tab sis tsis tshua muaj nyob rau hauv lub microscopic theem, nyob ntawm seb lub hauv paus chiv keeb ntawm qhov inhomogeneity.Hauv kev ua haujlwm no, nanoscale deg tshuaj heterogeneity kuaj pom los ntawm spectroscopic microscopy thiab chemometric tsom xam expectedly dominates decomposition thiab corrosion ntawm txias dov cerium hloov super duplex stainless hlau 2507 (SDSS) thaum nws kub deformation cwj pwm.lwm sab.Txawm hais tias xoo hluav taws xob photoelectron microscopy tau pom muaj qhov sib xws ntawm cov txheej txheem Cr2O3, txias dov SDSS pom cov txiaj ntsig tsis zoo vim qhov kev faib tawm hauv cheeb tsam ntawm Fe3+ nplua nuj nanoislands ntawm Fe / Cr oxide txheej.Qhov kev paub no ntawm qib atomic muab kev nkag siab tob ntawm stainless hlau corrosion thiab xav tias yuav pab tiv thaiv corrosion ntawm cov hlau zoo sib xws.
Txij li thaum lub invention ntawm stainless hlau, lub corrosion kuj ntawm ferrochromium alloys tau raug ntaus nqi mus rau chromium, uas tsim ib tug muaj zog oxide / oxyhydroxide exhibiting passivating cwj pwm nyob rau hauv feem ntau ib puag ncig.Piv nrog rau cov pa (austenitic thiab ferritic) stainless hlau, super duplex stainless hlau (SDSS) nrog zoo corrosion kuj muaj superior mechanical zog 1,2,3.Ua kom muaj zog txhua yam tso cai rau kev sib dua thiab ntau dua kev tsim qauv.Hauv qhov sib piv, SDSS kev lag luam muaj kev tiv thaiv siab rau pitting thiab crevice corrosion, ua rau lub neej ntev kev pab cuam thiab dav siv hauv kev tswj cov pa phem, ntim tshuaj, thiab kev lag luam offshore roj thiab roj 4.Txawm li cas los xij, qhov nqaim ntawm kev kho cua sov kub thiab tsis zoo formability cuam tshuam nws txoj kev siv dav dav.Yog li ntawd, SDSS tau raug hloov kho los txhim kho cov khoom saum toj no.Piv txwv li, Ce hloov kho thiab siab ntxiv ntawm N 6, 7, 8 tau qhia hauv 2507 SDSS (Ce-2507).Qhov tsim nyog concentration ntawm 0.08 wt.% tsawg lub ntiaj teb lub caij (Ce) muaj txiaj ntsig zoo rau cov khoom siv kho tshuab ntawm DSS, vim nws txhim kho cov nplej refinement thiab grain ciam zog.Hnav thiab corrosion kuj, tensile lub zog thiab tawm los lub zog, thiab kub ua hauj lwm kuj tau txhim kho9.Cov nitrogen ntau tuaj yeem hloov cov ntsiab lus nickel kim, ua rau SDSS tau txais txiaj ntsig ntau dua 10.
Tsis ntev los no, SDSS tau ua plastically deformed ntawm ntau qhov kub thiab txias (tsis tshua muaj kub, txias thiab kub) kom ua tiav cov cuab yeej zoo heev 6,7,8.Txawm li cas los xij, qhov zoo tshaj plaws corrosion kuj ntawm SDSS yog vim muaj ib tug nyias oxide zaj duab xis nyob rau saum npoo, uas yog cuam tshuam los ntawm ntau yam, xws li lub xub ntiag ntawm ntau theem nrog txawv grain ciam teb, pliaj precipitates thiab sib txawv tshuaj.Inhomogeneous microstructure ntawm ntau yam austenitic thiab ferritic theem yog deformed 7 .Yog li ntawd, txoj kev tshawb fawb ntawm microdomain cov khoom ntawm cov yeeb yaj kiab zoo li no nyob rau theem ntawm cov qauv hluav taws xob yog qhov tseem ceeb rau kev nkag siab SDSS corrosion thiab yuav tsum muaj cov txheej txheem kev sim ua haujlwm nyuaj.Txog rau tam sim no, cov txheej txheem ntog-rhiab heev xws li Auger electron spectroscopy11 thiab X-ray photoelectron spectroscopy12,13,14,15 thiab nyuaj X-ray photoelectron photoelectron system txawv, tab sis feem ntau tsis sib cais, cov tshuaj ntawm tib lub caij nyob rau hauv cov ntsiab lus sib txawv ntawm qhov chaw ntawm nanoscale.Ob peb cov kev tshawb fawb tsis ntev los no tau txuas cov oxidation hauv zos ntawm chromium rau qhov pom ntawm corrosion ntawm 17 austenitic stainless hlau, 18 martensitic stainless hlau, thiab SDSS 19, 20. Txawm li cas los xij, cov kev tshawb fawb no tau tsom mus rau cov nyhuv ntawm Cr heterogeneity (xws li, Cr3+ oxidation xeev) ntawm corrosion resistance.Lateral heterogeneity nyob rau hauv lub xeev oxidation ntawm cov ntsiab lus tuaj yeem tshwm sim los ntawm cov tebchaw sib txawv nrog tib lub ntsiab lus, xws li hlau oxides.Cov tebchaw no tau txais cov txheej txheem thermomechanically ua haujlwm me me ze ze rau ib leeg, tab sis sib txawv hauv cov ntsiab lus thiab oxidation state16,21.Yog li ntawd, nthuav tawm qhov kev puas tsuaj ntawm cov yeeb yaj kiab oxide thiab tom qab ntawd pitting yuav tsum muaj kev nkag siab ntawm qhov tsis sib xws ntawm qhov microscopic.Txawm hais tias cov kev xav tau no, kev ntsuas ntau yam xws li oxidation heterogeneity, tshwj xeeb tshaj yog cov hlau ntawm nano / atomic scale, tseem tsis muaj thiab lawv qhov tseem ceeb rau corrosion kuj tseem tsis tau tshawb nrhiav.Txog thaum tsis ntev los no, cov tshuaj hauv lub xeev ntawm ntau lub ntsiab lus, xws li Fe thiab Ca, tau piav qhia ntau npaum li cas ntawm cov qauv steel siv mos X-ray photoelectron microscopy (X-PEEM) hauv nanoscale synchrotron hluav taws xob chaw.Ua ke nrog chemically rhiab heev X-ray absorption spectroscopy (XAS) cov tswv yim, X-PEEM enables XAS ntsuas nrog siab spatial thiab spectral daws teeb meem, muab tshuaj cov ntaub ntawv hais txog lub elemental muaj pes tsawg leeg thiab nws chemical xeev nrog spatial daws mus rau nanometer scale 23 .Qhov kev soj ntsuam spectroscopic ntawm qhov chaw pib nyob rau hauv lub tshuab tsom iav ua kom yooj yim rau kev sim tshuaj lom neeg hauv zos thiab tuaj yeem ua rau pom kev hloov pauv tshuaj tsis tau tshawb nrhiav yav dhau los hauv Fe txheej.
Txoj kev tshawb no txuas ntxiv qhov zoo ntawm PEEM hauv kev tshawb xyuas cov tshuaj sib txawv ntawm nanoscale thiab nthuav qhia qhov kev pom zoo ntawm atomic-theem saum npoo ntawm kev tsom xam rau kev nkag siab txog tus cwj pwm corrosion ntawm Ce-2507.Nws siv K-txhais tau tias pawg chemometric data24 los qhia txog lub ntiaj teb tshuaj lom neeg muaj pes tsawg leeg (heterogeneity) ntawm cov ntsiab lus koom nrog, nrog rau lawv cov tshuaj hauv xeev tau nthuav tawm hauv cov ntaub ntawv txheeb cais.Tsis zoo li cov pa corrosion tshwm sim los ntawm chromium oxide zaj duab xis tawg, tam sim no tsis zoo passivation thiab tsis zoo corrosion kuj raug ntaus nqi rau hauv zos Fe3 + nplua nuj nanoislands ze ntawm Fe / Cr oxide txheej, uas tej zaum yuav muaj kev tawm tsam los ntawm kev tiv thaiv oxide.Nws tsim ib zaj duab xis nyob rau hauv qhov chaw thiab ua rau corrosion.
Tus cwj pwm corrosive ntawm deformed SDSS 2507 yog thawj zaug soj ntsuam siv electrochemical ntsuas.Ntawm daim duab.Daim duab 1 qhia txog Nyquist thiab Bode nkhaus rau cov qauv xaiv hauv acidic (pH = 1) aqueous daws ntawm FeCl3 ntawm chav tsev kub.Cov electrolyte raug xaiv ua raws li tus neeg sawv cev oxidizing muaj zog, ua tus cwj pwm nyiam ntawm zaj duab xis passivation kom tawg.Txawm hais tias cov khoom siv tsis tau nyob rau hauv chav tsev kub kub pitting, cov kev ntsuam xyuas no tau muab kev pom rau cov xwm txheej tsis zoo thiab cov txheej txheem tom qab corrosion.Qhov sib npaug ntawm Circuit Court (Daim duab 1d) tau siv los ua kom haum electrochemical impedance spectroscopy (EIS) spectra, thiab cov txiaj ntsig zoo sib xws tau pom nyob rau hauv Table 1. Tsis tiav ib nrab voj voog tshwm sim thaum kuaj cov tshuaj kho thiab cov qauv ua haujlwm kub, thaum qhov sib thooj compressed ib nrab lub voj voog tau txias dov (daim duab 1).Hauv EIS spectrum, lub voj voog ib nrab tuaj yeem suav tias yog qhov polarization tsis kam (Rp) 25,26.Rp ntawm cov tshuaj kho SDSS hauv Table 1 yog hais txog 135 kΩ cm-2, txawm li cas los xij rau kev ua haujlwm kub thiab txias dov SDSS peb tuaj yeem pom cov nqi qis dua ntawm 34.7 thiab 2.1 kΩ cm-2 raws li.Qhov kev txo qis hauv Rp no qhia tau tias muaj kev cuam tshuam ntawm cov yas deformation ntawm passivation thiab corrosion kuj, raws li qhia nyob rau hauv cov ntaub ntawv dhau los 27, 28, 29, 30.
ib Nyquist, b, c Bode impedance thiab theem daim duab, thiab ib tug sib npaug Circuit Court qauv rau d, qhov twg RS yog cov electrolyte tsis kam, Rp yog cov polarization tsis kam, thiab QCPE yog cov theem tsis tu ncua oxide siv los ua qauv tsis zoo tagnrho capacitance (n).Kev ntsuas EIS tau ua tiav ntawm qhov tsis muaj peev xwm thauj khoom.
Thawj qhov kev txiav txim tas mus li tau pom nyob rau hauv daim duab Bode thiab qhov siab zaus toj siab sawv cev rau cov electrolyte tsis kam RS26.Raws li qhov zaus txo qis, qhov impedance nce thiab pom lub kaum sab xis tsis zoo, qhia tias muaj peev xwm dominance.Lub kaum sab xis nce, khaws nws cov nqi siab tshaj plaws nyob rau hauv qhov dav dav, thiab tom qab ntawd txo qis (Daim duab 1c).Txawm li cas los xij, nyob rau hauv tag nrho peb qhov no tus nqi siab tshaj plaws yog tseem tsawg dua 90 °, qhia txog tus cwj pwm tsis zoo ntawm capacitive vim muaj kev cuam tshuam ntawm kev ua haujlwm.Yog li, QCPE lub caij tsis tu ncua (CPE) yog siv los sawv cev rau qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv los yog qhov tsis sib xws, tshwj xeeb tshaj yog nyob rau hauv cov nqe lus ntawm atomic scale, fractal geometry, electrode porosity, non-uniform potential, and dependent current distribution.Electrode geometry31,32.CPE impedance:
qhov twg j yog tus lej xav txog thiab ω yog angular zaus.QCPE yog ib qho kev ywj pheej tsis tu ncua qhov sib npaug rau qhov chaw qhib ntawm cov electrolyte.n yog tus naj npawb tsis muaj zog uas piav qhia qhov sib txawv ntawm qhov zoo tshaj plaws capacitive tus cwj pwm ntawm lub capacitor, piv txwv li qhov ze n yog rau 1, qhov ze CPE yog kom ntshiab capacitance, thiab yog tias n yog ze rau xoom, nws yog qhov tsis kam.Ib qho kev sib txawv me me ntawm n, ze rau 1, qhia txog tus cwj pwm tsis zoo ntawm lub ntsej muag tom qab kuaj polarization.QCPE ntawm txias dov SDSS yog ntau dua li cov khoom zoo sib xws, uas txhais tau hais tias qhov zoo ntawm qhov chaw tsis zoo li qub.
Raws li kev tiv thaiv corrosion feem ntau ntawm stainless hlau, cov ntsiab lus siab Cr ntawm SDSS feem ntau ua rau muaj kev tiv thaiv corrosion zoo tshaj ntawm SDSS vim tias muaj cov yeeb yaj kiab tiv thaiv oxide nyob rau saum npoo 17.Cov zaj duab xis passivating no feem ntau yog nplua nuj nyob rau hauv Cr3 + oxides thiab / los yog hydroxides, feem ntau integrating Fe2 +, Fe3 + oxides thiab / los yog (oxy) hydroxides 33.Txawm hais tias muaj qhov sib txawv ntawm qhov sib txawv, cov txheej txheej oxide passivating, thiab tsis pom kev puas tsuaj rau ntawm qhov chaw, raws li kev txiav txim siab los ntawm cov duab microscopic, 6,7 tus cwj pwm corrosion ntawm kub-ua hauj lwm thiab txias-dov SDSS yog sib txawv thiab yog li ntawd yuav tsum tau nyob rau hauv-tob kawm ntawm lub deformation microstructure thiab cov yam ntxwv ntawm cov hlau.
Lub microstructure ntawm deformed stainless hlau yog quantitatively soj ntsuam siv internal thiab synchrotron high-zog X-rays (Cov duab ntxiv 1, 2).Ib qho kev soj ntsuam ntxaws ntxaws muaj nyob rau hauv Cov Lus Qhia Ntxiv.Txawm hais tias lawv feem ntau sib haum mus rau hom theem tseem ceeb, qhov sib txawv ntawm cov theem ntim feem ntau pom, uas tau teev nyob rau hauv Cov Lus Qhia Ntxiv 1. Cov kev sib txawv no tuaj yeem cuam tshuam nrog cov theem tsis sib xws ntawm qhov chaw, nrog rau cov theem volumetric feem ua tiav ntawm qhov sib txawv.kuaj pom los ntawm X-ray diffraction.(XRD) nrog ntau lub zog ntawm qhov xwm txheej photons.Cov feem ntau dua ntawm austenite nyob rau hauv txias dov specimens, txiav txim los ntawm XRD los ntawm ib lub chaw soj nstuam qhov chaw, qhia tias passivation zoo dua thiab tom qab corrosion kuj zoo dua 35, thaum ntau qhov tseeb thiab cov txiaj ntsig txheeb xyuas qhia qhov sib txawv hauv theem proportions.Tsis tas li ntawd, qhov corrosion kuj ntawm steel kuj nyob ntawm qib ntawm grain refinement, grain loj txo, nce nyob rau hauv microdeformations thiab dislocation ceev uas tshwm sim thaum lub sij hawm thermomechanical kev kho mob36,37,38.Cov qauv ua haujlwm kub tau nthuav tawm ntau qhov ua tau zoo, qhia txog cov nplej me me, thaum lub nplhaib du pom nyob rau hauv cov kab mob khaub thuas dov (Ntxiv Fig. 3) qhia txog qhov tseem ceeb ntawm cov nplej ua kom zoo rau nanoscale hauv kev ua haujlwm dhau los 6, uas yuav tsum tau ua rau cov yeeb yaj kiab passivation.tsim thiab nce corrosion kuj.Qhov siab dua dislocation ntom feem ntau yog txuam nrog qis tsis kam rau pitting, uas pom zoo nrog kev ntsuas electrochemical.
Cov kev hloov hauv cov tshuaj hauv cov xeev ntawm microdomains ntawm cov ntsiab lus tseem ceeb tau raug tshawb fawb siv X-PEEM.Txawm hais tias muaj ntau ntawm cov ntsiab lus alloying, Cr, Fe, Ni thiab Ce39 tau raug xaiv ntawm no, vim Cr yog lub hauv paus tseem ceeb rau kev tsim cov yeeb yaj kiab passivation, Fe yog lub ntsiab tseem ceeb hauv cov hlau, thiab Ni txhim kho passivation thiab sib npaug ntawm ferrite-austenitic theem qauv thiab lub hom phiaj ntawm Ce hloov kho.Los ntawm kev kho lub zog ntawm cov hluav taws xob synchrotron, RAS tau coated los ntawm qhov chaw nrog cov yam ntxwv tseem ceeb ntawm Cr (ntug ​​L2.3), Fe (ntug L2.3), Ni (ntug L2.3) thiab Ce (ntug M4.5).Kub sib sau thiab txias dov Ce-2507 SDSS.Kev txheeb xyuas cov ntaub ntawv tsim nyog tau ua los ntawm kev sib koom ua ke ntawm lub zog calibration nrog cov ntaub ntawv luam tawm (xws li XAS 40, 41 ntawm Fe L2, 3 npoo).
Ntawm daim duab.Daim duab 2 qhia X-PEEM cov duab ntawm kev ua haujlwm kub (Fig. 2a) thiab txias-dov (Fig. 2d) Ce-2507 SDSS thiab sib thooj XAS npoo ntawm Cr thiab Fe L2,3 ntawm ib qho chaw cim.Lub L2,3 ntug ntawm XAS soj ntsuam cov tsis muaj 3d xeev tom qab electron photoexcitation ntawm lub spin-orbit splitting theem 2p3/2 (L3 ntug) thiab 2p1/2 (L2 ntug).Cov ntaub ntawv hais txog lub xeev valence ntawm Cr tau txais los ntawm XAS ntawm L2,3 ntug hauv daim duab 2b, e.Kev sib piv nrog cov kws txiav txim plaub ntug.42,43 tau pom tias plaub lub ncov tau pom nyob ze ntawm ntug L3, hu ua A (578.3 eV), B (579.5 eV), C (580.4 eV) thiab D (582.2 eV), xav txog octahedral Cr3+, sib haum rau Cr2O3 ion.Cov kev sim spectra pom zoo nrog cov theoretical xam pom nyob rau hauv panels b thiab e, tau los ntawm ntau lub sij hawm ntawm cov siv lead ua teb ntawm Cr L2.3 interface siv ib tug siv lead ua teb ntawm 2.0 eV44.Ob qhov chaw ntawm kub ua hauj lwm thiab txias dov SDSS yog coated nrog ib tug kuj zoo li txheej ntawm Cr2O3.
a X-PEEM thermal duab ntawm thermally deformed SDSS sib xws rau b Cr L2.3 ntug thiab c Fe L2.3 ntug, d X-PEEM thermal duab ntawm txias dov SDSS sib xws rau e Cr L2.3 ntug thiab f Fe L2.3 ntug sab (f).XAS spectra yog npaj rau ntawm qhov sib txawv spatial txoj hauj lwm cim rau ntawm cov duab thermal (a, d), cov kab txiv kab ntxwv dotted hauv (b) thiab (e) sawv cev rau qhov simulated XAS spectra ntawm Cr3+ nrog cov siv lead ua teb tus nqi ntawm 2.0 eV.Rau cov duab X-PEEM, siv lub thermal palette los txhim kho cov duab nyeem, qhov twg xim ntawm xiav mus rau liab yog proportional rau qhov siv ntawm X-ray nqus (los ntawm qis mus rau siab).
Txawm hais tias ib puag ncig chemical ntawm cov hlau no, cov tshuaj hauv lub xeev ntawm kev ntxiv ntawm Ni thiab Ce alloying ntsiab rau ob qho tib si cov qauv tseem tsis hloov.Daim duab ntxiv.Cov duab 5-9 qhia X-PEEM dluab thiab coj XAS spectra rau Ni thiab Ce ntawm ntau txoj haujlwm nyob rau saum npoo ntawm cov khoom kub-ua haujlwm thiab txias-dov.Ni XAS qhia cov oxidation xeev ntawm Ni2+ hla tag nrho qhov ntsuas ntawm qhov kub-ua haujlwm thiab txias-dov cov qauv (Kev Sib Tham Ntxiv).Nws yuav tsum tau muab sau tseg tias, nyob rau hauv cov ntaub ntawv ntawm kub-ua hauj lwm kuaj, lub XAS teeb liab ntawm Ce tsis tau pom, thaum nyob rau hauv cov ntaub ntawv ntawm txias-dov cov qauv, lub spectrum ntawm Ce3+ tau pom.Kev soj ntsuam ntawm Ce me ntsis hauv cov qauv txias-dov tau pom tias Ce feem ntau tshwm nyob rau hauv daim ntawv ntawm precipitates.
Hauv cov thermally deformed SDSS, tsis muaj kev hloov hauv zos hauv XAS ntawm Fe L2,3 ntug tau pom (Daim duab 2c).Txawm li cas los xij, Fe matrix micro-regionally hloov nws cov tshuaj hauv lub xeev ntawm xya qhov kev xaiv randomly xaiv ntawm SDSS txias, raws li qhia hauv daim duab 2f.Tsis tas li ntawd, txhawm rau kom tau txais lub tswv yim tseeb ntawm cov kev hloov pauv hauv lub xeev Fe ntawm cov chaw xaiv hauv daim duab 2f, cov kev tshawb fawb hauv cheeb tsam tau ua tiav (Fig. 3 thiab Supplementary Fig. 10) uas cov cheeb tsam me me raug xaiv.Lub XAS spectra ntawm Fe L2,3 ntug ntawm α-Fe2O3 systems thiab Fe2+ octahedral oxides tau ua qauv los ntawm ntau yam siv lead ua teb suav nrog siv lead ua teb ntawm 1.0 (Fe2+) thiab 1.0 (Fe3+)44. Peb nco ntsoov tias α-Fe2O3 thiab γ-Fe2O3 muaj qhov sib txawv hauv zos symmetries45,46, Fe3O4 muaj kev sib xyaw ntawm Fe2+ & Fe3+,47, thiab FeO45 raws li kev sib txawv ntawm Fe2+ oxide (3d6). Peb nco ntsoov tias α-Fe2O3 thiab γ-Fe2O3 muaj qhov sib txawv hauv zos symmetries45,46, Fe3O4 muaj kev sib xyaw ntawm Fe2+ & Fe3+,47, thiab FeO45 raws li kev sib txawv ntawm Fe2+ oxide (3d6).Nco ntsoov tias α-Fe2O3 thiab γ-Fe2O3 muaj qhov sib txawv hauv zos symmetries45,46, Fe3O4 ua ke ob qho tib si Fe2+ thiab Fe3+,47 thiab FeO45 nyob rau hauv daim ntawv ntawm formal divalent oxide Fe2+ (3d6).Nco ntsoov tias α-Fe2O3 thiab γ-Fe2O3 muaj qhov sib txawv hauv zos symmetries45,46, Fe3O4 muaj kev sib xyaw ntawm Fe2+ thiab Fe3+,47 thiab FeO45 ua raws li kev sib txawv ntawm Fe2+ oxide (3d6).Tag nrho Fe3+ ions hauv α-Fe2O3 tsuas muaj Oh txoj haujlwm xwb, thaum γ-Fe2O3 feem ntau yog sawv cev los ntawm Fe3+ t2g [Fe3 + 5/3V1/3]eg O4 spinel nrog cov haujlwm tsis txaus hauv xws li txoj haujlwm.Yog li, Fe3 + ions hauv γ-Fe2O3 muaj ob txoj haujlwm Td thiab Oh.Raws li tau hais nyob rau hauv ib daim ntawv dhau los, 45 txawm hais tias qhov sib piv ntawm ob qhov sib txawv, lawv qhov kev siv qhov sib piv piv txwv li / t2g yog ≈1, thaum nyob rau hauv cov ntaub ntawv no qhov pom kev siv piv piv txwv eg / t2g yog hais txog 1. Qhov no tsis suav nrog qhov muaj peev xwm uas nyob rau hauv qhov xwm txheej tam sim no tsuas yog Fe3+ tam sim no.Xav txog cov ntaub ntawv ntawm Fe3O4 nrog Fe2+ thiab Fe3+, thawj qhov tshwj xeeb paub tias muaj qhov tsis muaj zog (muaj zog) L3 ntug rau Fe qhia tias me me (loj) tsis muaj lub xeev t2g.Qhov no siv rau Fe2+ (Fe3+), uas qhia tau hais tias thawj qhov tshwj xeeb ntawm kev nce ntxiv qhia txog kev nce hauv cov ntsiab lus ntawm Fe2 + 47.Cov txiaj ntsig no qhia tau hais tias kev sib koom ua ke ntawm Fe2 + thiab γ-Fe2O3, α-Fe2O3 thiab / lossis Fe3O4 dominates ntawm qhov txias-dov ntawm cov khoom sib xyaw.
Enlarged photoelectron thermal imaging dluab ntawm XAS spectra (a, c) thiab (b, d) hla Fe L2,3 ntug ntawm ntau qhov chaw nyob hauv cheeb tsam xaiv 2 thiab E hauv daim duab.2d ib.
Cov ntaub ntawv tau txais kev sim (Fig. 4a thiab Supplementary Fig. 11) yog plotted thiab muab piv nrog cov ntaub ntawv rau cov ntshiab compounds 40, 41, 48. Peb hom sib txawv ntawm kev soj ntsuam soj ntsuam Fe L-edge XAS spectra (XAS- 1, XAS-2 thiab XAS-3: Fig. 4a).Tshwj xeeb tshaj yog, spectrum 2-a (xws li XAS-1) nyob rau hauv daim duab 3b ua raws li spectrum 2-b (labeled XAS-2) tau pom nyob rau tag nrho cheeb tsam nrhiav pom, thaum lub spectrum zoo li E-3 tau pom nyob rau hauv daim duab 3d (labeled XAS-3) tau pom nyob rau hauv tej qhov chaw.Raws li txoj cai, plaub qhov kev txwv tau siv los txheeb xyuas lub xeev valence uas twb muaj lawm hauv cov qauv hauv qab no: (1) spectral yam ntxwv L3 thiab L2, (2) lub zog ntawm cov yam ntxwv L3 thiab L2, (3) lub zog sib txawv L3-L2., (4) L2 / L3 siv qhov sib piv.Raws li kev soj ntsuam pom (Fig. 4a), tag nrho peb Fe Cheebtsam, uas yog, Fe0, Fe2+, thiab Fe3+, muaj nyob rau ntawm SDSS nto nyob rau hauv kev kawm.Qhov ntsuas qhov sib piv L2 / L3 kuj tau qhia tias muaj tag nrho peb yam.
a Simulated XAS spectra of Fe nrog pom peb qhov kev sim sib txawv (cov kab khoom XAS-1, XAS-2 thiab XAS-3 sib raug rau 2-a, 2-b thiab E-3 hauv daim duab 2 thiab 3) Kev sib piv, Octahedrons Fe2+, Fe3+ nrog crystal field values ​​.5e V, 1. bd (XAS-1, XAS-2, XAS-3) thiab cov ntaub ntawv sib raug zoo LCF cov ntaub ntawv (khoom dub kab), thiab tseem nyob rau hauv daim ntawv XAS-3 spectra nrog Fe3O4 (mixed xeev ntawm Fe) thiab Fe2O3 (ntshiab Fe3+) qauv.
Ib txoj kab sib xyaw ua ke (LCF) ntawm peb tus qauv 40, 41, 48 tau siv los ntsuas cov hlau oxide muaj pes tsawg leeg.LCF tau siv rau peb xaiv Fe L-edge XAS spectra uas qhia qhov sib txawv siab tshaj plaws, xws li XAS-1, XAS-2 thiab XAS-3, raws li qhia hauv daim duab 4b-d.Rau LCF fittings, 10% Fe0 tau coj mus rau hauv tus account nyob rau hauv tag nrho cov rooj plaub vim qhov tseeb tias peb tau pom ib tug me me ledge nyob rau hauv tag nrho cov ntaub ntawv, thiab kuj yog vim lub fact tias hlau hlau yog lub ntsiab ntawm cov hlau. Qhov tseeb, qhov tob ntawm kev soj ntsuam ntawm X-PEEM rau Fe (~ 6 nm) 49 yog qhov loj dua li qhov kwv yees oxidation txheej tuab (me ntsis> 4 nm), tso cai rau kev tshawb pom cov teeb liab los ntawm cov hlau matrix (Fe0) hauv qab txheej passivation. Qhov tseeb, qhov tob ntawm kev soj ntsuam ntawm X-PEEM rau Fe (~ 6 nm) 49 yog qhov loj dua li qhov kwv yees oxidation txheej tuab (me ntsis> 4 nm), tso cai rau kev tshawb pom cov teeb liab los ntawm cov hlau matrix (Fe0) hauv qab txheej passivation. Действительно, пробная глубина X-PEEM для Fe (~ 6 нм)49 больше, чем предполагаемая толщина слоя 4 яки (спмоя 4 яки) озволяет обнаружить сигнал от железной матрицы (Fe0) под пассивирующим слоем. Qhov tseeb, qhov kev sojntsuam X-PEEM qhov tob rau Fe (~ 6 nm) 49 yog ntau dua li qhov xav tau ntawm cov txheej txheem oxidation (me ntsis> 4 nm), uas ua rau nws muaj peev xwm txheeb xyuas cov teeb liab los ntawm cov hlau matrix (Fe0) hauv qab txheej passivation.事实上，X-PEEM 对Fe (~ 6 nm) 49 的检测深度大于估计的氧化层厚度（略> 4 nm），允许检测杸自钒0) npe.事实上 ， X-PEEM 对 Fe (~ 6 nm) 49 的 检测 深度 大于的 氧化层 厚度 略 略 > 4 nm) 允许化棵方铁基体 (fe0) 的。 信号 信号 信号 信号 信号 信号 信号 信号 信号 信号Фактически, глубина обнаружения Fe (~ 6 нм) 49 с помощью X-PEEM больше, чем предполагаемая тонгнемо тонгнина окс ), что позволяет обнаруживать сигнал от железной матрицы (Fe0) ниже пассивирующего слоя. Qhov tseeb, qhov tob ntawm kev tshawb pom ntawm Fe (~ 6 nm) 49 los ntawm X-PEEM yog ntau dua li qhov xav tau ntawm cov txheej txheem oxide (me ntsis> 4 nm), uas tso cai rau kev tshawb pom cov teeb liab los ntawm cov hlau matrix (Fe0) hauv qab txheej passivation. .Ntau qhov sib xyaw ua ke ntawm Fe2+ thiab Fe3+ tau ua tiav los nrhiav cov kev daws teeb meem zoo tshaj plaws rau cov ntaub ntawv soj ntsuam.Ntawm daim duab.4b qhia txog XAS-1 spectrum rau kev sib xyaw ntawm Fe2 + thiab Fe3 +, qhov sib piv ntawm Fe2 + thiab Fe3 + zoo ib yam li ntawm 45%, qhia tias sib xyaw oxidation xeev ntawm Fe.Thaum rau XAS-2 spectrum, feem pua ​​​​ntawm Fe2+ thiab Fe3+ dhau los ua ~ 30% thiab 60%, feem.Fe2+ ​​tsawg dua Fe3+.Qhov piv ntawm Fe2 + rau Fe3, sib npaug rau 1: 2, txhais tau hais tias Fe3O4 tuaj yeem tsim los ntawm tib qhov sib piv ntawm Fe ions.Tsis tas li ntawd, rau XAS-3 spectrum, qhov feem pua ​​​​ntawm Fe2 + thiab Fe3 + dhau los ua ~ 10% thiab 80%, uas qhia tau tias muaj kev hloov pauv ntau dua ntawm Fe2 + rau Fe3 +.Raws li tau hais los saum no, Fe3 + tuaj yeem los ntawm α-Fe2O3, γ-Fe2O3 lossis Fe3O4.Txhawm rau nkag siab qhov feem ntau ntawm Fe3+, XAS-3 spectrum tau npaj nrog cov qauv Fe3+ sib txawv hauv daim duab 4e, qhia qhov zoo sib xws nrog ob tus qauv thaum xav txog B ncov.Txawm li cas los xij, qhov kev siv ntawm lub xub pwg peaks (A: los ntawm Fe2 +) thiab B / A siv piv qhia tias cov spectrum ntawm XAS-3 nyob ze, tab sis tsis coincide nrog lub spectrum ntawm γ-Fe2O3.Piv rau tej γ-Fe2O3, Fe 2p XAS ncov ntawm A SDSS muaj ib qho kev siv zog me ntsis (Fig. 4e), uas qhia tias muaj kev siv ntau dua ntawm Fe2+.Txawm hais tias lub spectrum ntawm XAS-3 zoo ib yam li ntawm γ-Fe2O3, qhov twg Fe3 + yog tam sim no ntawm Oh thiab Td txoj haujlwm, kev txheeb xyuas ntawm cov xeev sib txawv thiab kev sib koom tes tsuas yog raws li L2,3 ntug lossis L2 / L3 qhov sib piv tseem yog qhov kev tshawb fawb txuas ntxiv.kev sib tham vim qhov nyuaj ntawm ntau yam uas cuam tshuam rau qhov kawg spectrum41.
Ntxiv rau qhov sib txawv spectral nyob rau hauv cov tshuaj hauv lub xeev ntawm cov cheeb tsam xaiv ntawm kev txaus siab tau piav qhia saum toj no, lub ntiaj teb tshuaj heterogeneity ntawm cov ntsiab lus tseem ceeb Cr thiab Fe kuj raug soj ntsuam los ntawm kev faib tag nrho XAS spectra tau txais ntawm cov qauv saum npoo siv K- txhais tau tias kev sib koom ua ke.Lub Cr L edge profiles tsim ob qhov chaw zoo tshaj plaws faib ua pawg hauv cov khoom kub-ua haujlwm thiab txias-dov cov qauv qhia hauv Figs.5. Nws yog qhov tseeb tias tsis muaj kev hloov pauv hauv zos tau pom tias zoo sib xws, txij li ob lub centroids ntawm XAS Cr spectra yog sib piv.Cov duab spectral ntawm ob pawg no yuav luag zoo ib yam rau cov sib xws rau Cr2O342, uas txhais tau hais tias Cr2O3 cov khaubncaws sab nraud povtseg kuj sib npaug ntawm SDSS.
Cr L K-txhais tau hais tias ntug cheeb tsam pawg, thiab b yog qhov sib thooj XAS centroids.Cov txiaj ntsig ntawm K- txhais tau tias X-PEEM kev sib piv ntawm txias-dov SDSS: c Cr L2.3 ntug cheeb tsam ntawm K- txhais tau tias pawg thiab d sib thooj XAS centroids.
Txhawm rau piav qhia txog FeL ntug daim duab qhia kev nyuaj, plaub thiab tsib pawg ua kom zoo dua qub thiab lawv cov centroids cuam tshuam (spectral profiles) tau siv rau cov qauv ua haujlwm kub thiab txias dov, feem.Yog li, qhov feem pua ​​​​(%) ntawm Fe2+ thiab Fe3+ tuaj yeem tau txais los ntawm kev haum rau LCF qhia hauv daim duab.4.Lub peev xwm pseudoelectrode Epseudo ua haujlwm ntawm Fe0 tau siv los nthuav tawm cov microchemical inhomogeneity ntawm cov oxide zaj duab xis saum npoo.Epseudo yog kwv yees kwv yees los ntawm txoj cai sib xyaw,
where \(\rm{E}_{\rm{Fe}/\rm{Fe}^{2 + (3 + )}}\) equals \(\rm{Fe} + 2e^ – \rm { Fe}^{2 + (3 + )}\), 0.440 and 0.036 V.Cov cheeb tsam uas muaj peev xwm qis dua muaj cov ntsiab lus siab dua ntawm Fe3 + compound.Lub peev xwm faib rau hauv cov qauv thermally deformed muaj cov cim txheej nrog qhov kev hloov siab tshaj plaws ntawm 0.119 V (Fig. 6a, b).Qhov kev faib tawm uas muaj peev xwm no muaj feem cuam tshuam nrog thaj chaw saum npoo av (Fig. 6a).Tsis muaj lwm yam kev hloov pauv nyob rau hauv lub hauv paus laminar sab hauv tau pom (Daim duab 6b).Ntawm qhov tsis sib xws, rau kev sib txuas ntawm cov oxides sib txawv nrog cov ntsiab lus sib txawv ntawm Fe2+ thiab Fe3+ hauv cov khaub thuas dov SDSS, ib tus tuaj yeem soj ntsuam qhov tsis sib xws ntawm cov pseudopotential (Fig. 6c, d).Fe3 + oxides thiab / lossis (oxy) hydroxides yog cov khoom tseem ceeb ntawm xeb hauv cov hlau thiab yog permeable rau oxygen thiab dej 50.Nyob rau hauv cov ntaub ntawv no, cov Islands tuaj nplua nuj nyob rau hauv Fe3+ raug suav hais tias yog muab faib hauv zos thiab tuaj yeem suav tias yog thaj chaw corroded.Nyob rau tib lub sij hawm, gradient nyob rau hauv lub peev xwm teb, es tsis yog tus nqi ntawm lub peev xwm, yuav siv tau raws li ib qho kev qhia rau lub localization ntawm active corrosion sites.Qhov kev faib tsis sib xws ntawm Fe2 + thiab Fe3 + ntawm qhov chaw txias txias SDSS tuaj yeem hloov pauv hauv zos chemistry thiab muab qhov chaw ua haujlwm ntau dua thaum lub sij hawm oxide zaj duab xis tawg thiab cov tshuaj tiv thaiv corrosion, tso cai rau lub hauv paus hlau matrix mus txuas ntxiv mus rau corrode, uas ua rau hauv heterogeneity.cov khoom thiab txo cov khoom tiv thaiv ntawm cov txheej txheem passivating.
K- txhais tau hais tias pawg thiab sib txuas XAS centroids hauv Fe L2.3 ntug cheeb tsam ntawm kub-deformed X-PEEM ac thiab df ntawm txias-dov SDSS.a, d K-txhais tau tias pawg phiaj xwm sib tshooj ntawm X-PEEM cov duab.Qhov xam pseudoelectrode muaj peev xwm (Epseudo) tau hais nrog rau K- txhais tau tias pawg phiaj xwm.Lub ci ci ntawm X-PEEM duab, zoo li cov xim hauv daim duab 2 yog proportional rau X-ray absorption siv.
Qhov sib txawv ntawm Cr tab sis cov tshuaj sib txawv ntawm Fe ua rau muaj qhov sib txawv oxide zaj duab xis puas thiab corrosion qauv hauv kub ua hauj lwm thiab txias dov Ce-2507.Cov cuab yeej no ntawm txias dov Ce-2507 tau kawm zoo.Hais txog kev tsim cov oxides thiab hydroxides ntawm Fe nyob rau hauv lub ambient cua nyob rau hauv no yuav luag tsis ua hauj lwm, cov tshuaj tiv thaiv yog raws li nram no:
Cov kev tshwm sim saum toj no tshwm sim hauv cov xwm txheej hauv qab no raws li X-PEEM tsom xam.Lub xub pwg me me sib xws rau Fe0 yog txuam nrog cov hlau hauv qab hlau.Cov tshuaj tiv thaiv ntawm metallic Fe nrog rau ib puag ncig ua rau tsim Fe (OH) 2 txheej (kev sib npaug (5)), uas txhim kho Fe2+ teeb liab hauv Fe L-edge XAS.Kev raug cua ntev ntev tuaj yeem ua rau tsim Fe3O4 thiab / lossis Fe2O3 oxides tom qab Fe (OH) 252,53.Ob daim ntawv ruaj khov ntawm Fe, Fe3O4 thiab Fe2O3, kuj tuaj yeem tsim nyob rau hauv Cr3 + nplua nuj txheej tiv thaiv, uas Fe3O4 nyiam cov qauv zoo ib yam thiab nplaum.Lub xub ntiag ntawm ob qho tib si tshwm sim hauv cov xeev sib xyaw oxidation (XAS-1 spectrum).XAS-2 spectrum feem ntau sib raug rau Fe3O4.Thaum qhov kev soj ntsuam ntawm XAS-3 spectra nyob rau hauv ntau qhov chaw qhia ua tiav kev hloov pauv mus rau γ-Fe2O3.Txij li thaum qhov tob tob ntawm lub unfolded X-rays yog hais txog 50 nm, lub teeb liab los ntawm cov txheej txheem qis ua rau muaj kev siv ntau dua ntawm A ncov.
XPA spectrum qhia tau hais tias Fe tivthaiv hauv oxide zaj duab xis muaj txheej txheej txheej ua ke nrog Cr oxide txheej.Nyob rau hauv sib piv rau cov cim qhia ntawm passivation vim lub zos inhomogeneity ntawm Cr2O3 thaum lub sij hawm corrosion, txawm tias cov txheej txheem ntawm Cr2O3 nyob rau hauv cov hauj lwm no, tsis tshua muaj corrosion kuj yog pom nyob rau hauv cov ntaub ntawv no, tshwj xeeb tshaj yog rau cov qauv txias-dov.Cov cwj pwm pom tau tuaj yeem nkag siab tias yog qhov heterogeneity ntawm cov tshuaj oxidation xeev nyob rau hauv cov txheej txheem sab saud (Fe), uas cuam tshuam rau kev ua haujlwm corrosion.Vim tib lub stoichiometry ntawm txheej sab sauv (hlau oxide) thiab qis txheej (chromium oxide) 52,53 zoo dua kev sib cuam tshuam (adhesion) ntawm lawv ua rau qeeb thauj cov hlau los yog oxygen ions nyob rau hauv lub lattice, uas, nyob rau hauv lem, ua rau ib tug nce nyob rau hauv corrosion kuj.Yog li ntawd, ib qho kev sib txuas txuas ntxiv mus, piv txwv li ib lub xeev oxidation ntawm Fe, yog qhov zoo dua rau kev hloov pauv stoichiometric.Lub tshav kub-deformed SDSS muaj ib tug ntau yam saum npoo, ib tug denser tiv thaiv txheej, thiab zoo corrosion kuj.Whereas rau txias-dov SDSS, lub xub ntiag ntawm Fe3 +-nplua nuj Islands tuaj nyob rau hauv cov txheej txheem tiv thaiv ua txhaum txoj kev ncaj ncees ntawm qhov chaw thiab ua rau galvanic corrosion nrog rau cov nyob ze substrate, uas ua rau ib tug ntse poob nyob rau hauv Rp (Table 1).EIS spectrum thiab nws cov corrosion kuj raug txo.Nws tuaj yeem pom tau tias qhov chaw faib khoom hauv zos ntawm Fe3 + nplua nuj Islands tuaj vim yog cov yas deformation feem ntau cuam tshuam rau kev tiv thaiv corrosion, uas yog qhov ua tiav hauv txoj haujlwm no.Yog li, txoj kev tshawb no nthuav tawm cov duab spectroscopic microscopic ntawm kev txo qis hauv kev tiv thaiv corrosion ntawm SDSS cov qauv kawm los ntawm cov txheej txheem yas deformation.
Tsis tas li ntawd, txawm hais tias tsis tshua muaj lub ntiaj teb alloying nyob rau hauv dual-theem steels qhia tau hais tias kev ua tau zoo dua, kev sib cuam tshuam ntawm cov khoom siv ntxiv nrog rau tus neeg hlau matrix nyob rau hauv cov nqe lus ntawm corrosion cwj pwm raws li spectroscopic microscopy tseem elusive.Cov tsos ntawm Ce teeb liab (ntawm XAS M-edges) tshwm tsuas yog nyob rau hauv ob peb qhov chaw thaum lub sij hawm txias dov, tab sis ploj thaum lub sij hawm kub deformation ntawm SDSS, qhia lub zos nag lossis daus ntawm Ce nyob rau hauv cov hlau matrix, es tsis yog homogeneous alloying.Thaum tsis txhim kho cov cuab yeej cuab tam ntawm SDSS6,7, qhov muaj cov ntsiab lus hauv ntiaj teb tsawg txo qhov loj ntawm kev suav thiab xav tias yuav txwv tsis pub pitting hauv cheeb tsam thawj 54.
Hauv kev xaus, qhov haujlwm no nthuav tawm cov txiaj ntsig ntawm qhov chaw heterogeneity ntawm corrosion ntawm 2507 SDSS hloov nrog cerium los ntawm kev txheeb xyuas cov ntsiab lus tshuaj ntawm nanoscale Cheebtsam.Peb teb cov lus nug yog vim li cas stainless hlau corrodes txawm nyob rau hauv ib tug tiv thaiv oxide txheej los ntawm quantifying nws microstructure, nto chemistry, thiab teeb liab ua siv K- txhais tau tias pawg.Nws tau raug tsim los hais tias cov Islands tuaj nplua nuj nyob rau hauv Fe3+, suav nrog lawv cov octahedral thiab tetrahedral kev sib koom ua ke nrog rau tag nrho cov yam ntxwv ntawm kev sib xyaw Fe2 + / Fe3 +, yog qhov chaw ntawm kev puas tsuaj thiab corrosion ntawm txias-dov oxide zaj duab xis SDSS.Nanoislands dominated los ntawm Fe3 + ua rau tsis zoo corrosion kuj txawm nyob rau hauv lub xub ntiag ntawm ib tug txaus stoichiometric Cr2O3 passivating txheej.Ntxiv rau cov txheej txheem kev nce qib hauv kev txiav txim siab cov txiaj ntsig ntawm nanoscale tshuaj heterogeneity ntawm corrosion, kev ua haujlwm tsis tu ncua yuav tsum txhawb nqa cov txheej txheem engineering los txhim kho corrosion tsis kam ntawm stainless hlau thaum lub sij hawm steelmaking.
Txhawm rau npaj Ce-2507 SDSS ingot siv nyob rau hauv txoj kev tshawb no, ib qho kev sib xyaw ua ke suav nrog Fe-Ce master alloy kaw nrog lub raj hlau ntshiab tau yaj hauv 150 kg nruab nrab zaus induction rauv los tsim cov hlau molten thiab nchuav rau hauv pwm.Qhov ntsuas tshuaj muaj pes tsawg leeg (wt%) yog teev nyob rau hauv Daim Ntawv Ntxiv 2. Ingots yog thawj kub forged rau hauv cov blocks.Tom qab ntawd nws yog annealed ntawm 1050 ° C rau 60 min kom tau cov hlau nyob rau hauv lub xeev ntawm ib tug tov khoom, thiab ces quenched nyob rau hauv dej mus rau chav tsev kub.Cov qauv kawm tau kawm hauv kev nthuav dav siv TEM thiab DOE los kawm cov theem, qhov loj me thiab morphology.Cov ncauj lus kom ntxaws ntxiv txog cov qauv thiab cov txheej txheem tsim khoom tuaj yeem pom hauv lwm qhov chaw 6,7.
Cov qauv cylindrical (φ10 mm × 15 mm) rau kev kub compression tau ua tiav kom lub axis ntawm lub tog raj kheej yog sib npaug rau cov kev taw qhia deformation ntawm lub thaiv.High-temperature compression tau ua los ntawm ntau qhov kub thiab txias hauv thaj tsam ntawm 1000-1150 ° C siv Gleeble-3800 thermal simulator ntawm tus nqi tsis tu ncua nyob rau hauv thaj tsam ntawm 0.01-10 s-1.Ua ntej deformation, cov qauv raug rhuab ntawm tus nqi ntawm 10 ° C s-1 rau 2 min ntawm qhov kub xaiv kom tshem tawm qhov kub ntawm gradient.Tom qab ua tiav qhov ntsuas kub tsis sib xws, tus qauv tau deformed rau qhov tseeb tus nqi ntawm 0.7.Tom qab deformation, cov qauv tau quenched tam sim ntawd nrog dej los khaws cov qauv deformed.Tom qab ntawd lub hardened specimen txiav mus rau hauv parallel mus rau lub compression kev taw qhia.Rau qhov kev tshawb fawb tshwj xeeb no, peb xaiv cov qauv uas muaj qhov kub thiab txias ntawm 1050 ° C, 10 s-1 vim qhov pom microhardness siab dua lwm cov qauv 7.
Loj (80 × 10 × 17 mm3) cov qauv ntawm cov khoom siv Ce-2507 tau siv hauv LG-300 peb-theem asynchronous ob-yob zeb nrog cov cuab yeej zoo tshaj plaws ntawm tag nrho lwm cov deformation theem6.Tus nqi strain thiab thickness txo rau txhua txoj kev yog 0.2 m·s-1 thiab 5%, feem.
Ib qho Autolab PGSTAT128N electrochemical workstation tau siv rau SDSS electrochemical ntsuas tom qab txias dov mus rau 90% txo nyob rau hauv thickness (1.0 sib npaug qhov tseeb hom) thiab tom qab kub nias ntawm 1050 ° C rau 10 s-1 mus rau ib tug tseeb hom ntawm 0.7.Lub chaw ua haujlwm muaj peb-electrode cell nrog cov calomel saturated electrode raws li cov khoom siv electrode, graphite counter electrode, thiab cov qauv SDSS ua cov electrode ua haujlwm.Cov qauv raug txiav rau hauv lub tog raj kheej nrog txoj kab uas hla ntawm 11.3 hli, mus rau sab ntawm cov xov tooj tooj liab tau soldered.Cov qauv tom qab ntawd kho nrog epoxy, tawm hauv qhov chaw ua haujlwm qhib ntawm 1 cm2 raws li cov khoom siv hluav taws xob ua haujlwm (hauv qab ntawm cov qauv cylindrical).Ceev faj thaum kho cov epoxy thiab tom qab xuab zeb thiab polishing kom tsis txhob tawg.Cov chaw ua haujlwm tau hauv av thiab polished nrog lub pob zeb diamond polishing ncua kev kawm nrog ib qho me me ntawm 1 μm, ntxuav nrog dej distilled thiab ethanol, thiab ziab hauv huab cua txias.Ua ntej kev ntsuas electrochemical, cov qauv polished tau raug rau huab cua rau ob peb hnub los tsim cov oxide zaj duab xis.Cov kua dej ntawm FeCl3 (6.0 wt%), stabilized rau pH = 1.0 ± 0.01 nrog HCl raws li ASTM cov lus pom zoo, yog siv los ua kom cov corrosion ntawm stainless hlau 55 vim nws yog corrosive nyob rau hauv lub xub ntiag ntawm chloride ions nrog ib tug muaj zog oxidizing muaj peev xwm thiab tsis tshua muaj pH Environmental qauv G48 thiab A2.Muab cov qauv tso rau hauv qhov kev tshuaj ntsuam xyuas rau 1 teev kom ncav cuag lub xeev khov kho ua ntej ua qhov ntsuas.Rau cov kev daws teeb meem, kub-tsim, thiab txias-dov cov qauv, impedance ntsuas tau ua nyob rau hauv qhib Circuit Court muaj peev xwm (OPC) ntawm 0.39, 0.33, thiab 0.25 V, raws li, nyob rau hauv lub zaus ntawm 1 105 mus rau 0.1 Hz nrog ib tug amplitude ntawm 5 mV.Tag nrho cov tshuaj ntsuam xyuas tau rov ua dua yam tsawg kawg 3 zaug nyob rau hauv tib yam mob los xyuas kom meej cov ntaub ntawv rov tsim dua tshiab.
Rau HE-SXRD kev ntsuas, cov duab plaub duplex steel blocks ntsuas 1 × 1 × 1.5 mm3 tau ntsuas los ntsuas cov kab teeb theem ntawm Brockhouse high-zog wiggler ntawm CLS, Canada56.Kev sau cov ntaub ntawv tau ua nyob rau hauv Debye-Scherrer geometry los yog kis tau tus mob geometry ntawm chav tsev kub.X-ray wavelength calibrated nrog LaB6 calibrator yog 0.212561 Å, uas sib haum mus rau 58 keV, uas yog ntau dua li Cu Kα (8 keV) feem ntau siv los kuaj X-ray qhov chaw.Cov qauv yog nyob ntawm qhov deb ntawm 740 mm los ntawm lub ntes.Qhov ntsuas qhov ntim ntawm txhua tus qauv yog 0.2 × 0.3 × 1.5 mm3, uas yog txiav txim siab los ntawm cov nqaj loj thiab cov qauv tuab.Tag nrho cov ntaub ntawv tau sau los ntawm Perkin Elmer cheeb tsam ntes, tiaj tus X-ray detector, 200 µm pixels, 40 × 40 cm2 siv lub sij hawm raug ntawm 0.3 s thiab 120 ntas.
X-PEEM kev ntsuas ntawm ob lub qauv xaiv tau ua tiav ntawm Beamline MAXPEEM PEEM kawg chaw nres tsheb hauv MAX IV lub chaw kuaj mob (Lund, Sweden).Cov qauv tau npaj ib yam li rau kev ntsuas electrochemical.Cov qauv npaj tau khaws cia hauv huab cua rau ob peb hnub thiab degassed hauv lub tshuab nqus tsev ultrahigh ua ntej raug irradiated nrog synchrotron photons.Lub zog daws teeb meem ntawm kab kab tau txais los ntawm kev ntsuas cov ion yield spectrum nyob rau hauv cheeb tsam excitation ntawm N 1 s mus rau 1 \(\pi _g^ \ast\) ze hv = 401 eV nyob rau hauv N2 nrog rau dependence ntawm photon zog ntawm E3/2 , 57. Kwv yees li spectra muab lub zog ntawm ΔE . Yog li ntawd, lub beamline zog daws teeb meem yog kwv yees li E / ∆E = 700 eV / 0.3 eV > 2000 thiab flux ≈1012 ph/s los ntawm kev siv ib tug hloov kho SX-700 monochromator nrog ib tug Si 1200-kab mm-1 grating rau Fe ntug 2p, L2 thiab 3 ntug Ce M4,5 ntug. Yog li ntawd, lub beamline zog daws teeb meem yog kwv yees li E / ∆E = 700 eV / 0.3 eV > 2000 thiab flux ≈1012 ph/s los ntawm kev siv ib tug hloov SX-700 monochromator nrog ib tug Si 1200-kab mm−1 grating rau Fe ntug 2p, L2 thiab L2. Ce M4.5 ntug. Таким образом, энергетическое разрешение канала пучка было оценено как E/∆E = 700 эВ / 0,3 э ∆ 2000 от прест / 2000 и ользовании модифицированного монохроматора SX-700 с решеткой Si 1200 штрихов/мм для Fe кромка 2p L2,3, 2 кр, L2,3, 2 кр, 2, 3 thiab кромка Ce M4,5. Yog li, lub zog daws teeb meem ntawm cov kab hluav taws xob tau kwv yees li E / ∆E = 700 eV / 0.3 eV> 2000 thiab flux ≈1012 f / s siv qhov hloov kho SX-700 monochromator nrog Si grating ntawm 1200 kab / hli rau Fe edge 2p L2 edge , L2, 3 p. M4.5.因此，光束线能量分辨率估计为E/ΔE = 700 eV/0.3 eV > 2000 和通量≈1012 ph/s, 通过忦 1012 ph/s, 通过忦 2mm 牔S栅的改进的SX-700 单色器用于Fe 2p L2,3 边缘、Cr 2p L2,3 边缘、Ni 2p L2,3 边缘和Ce M4,5 边缘。因此 ， 光束线 能量 分辨率 为 为 δe = 700 EV/0.3 EV> 2000 和 ≈1012 有用 mm 2 帺 用 1 帽甦光栅 改进的 SX-700 单色器 于 于 用用 Fe 2p L2.3 边缘、Cr 2p L2.3 边缘、Ni 2p 用 用 Fe 2p L2.3 边缘。Yog li, thaum siv hloov kho SX-700 monochromator nrog 1200 kab Si grating.3, Cr edge 2p L2.3, Ni edge 2p L2.3 thiab Ce edge M4.5.Luam theej duab photon zog hauv 0.2 eV cov kauj ruam.Ntawm txhua lub zog, PEEM cov duab raug kaw siv TVIPS F-216 fiber ntau-coupled CMOS ntes nrog 2 x 2 bins, uas muab kev daws teeb meem ntawm 1024 × 1024 pixels hauv 20 µm thaj chaw saib.Lub sij hawm raug ntawm cov duab yog 0.2 s, nruab nrab 16 ntas.Lub photoelectron duab zog yog xaiv nyob rau hauv xws li ib txoj kev raws li muab lub siab tshaj plaws thib ob electron teeb liab.Txhua qhov kev ntsuas tau ua tiav ntawm qhov xwm txheej ib txwm siv cov kab hluav taws xob polarized photon.Xav paub ntau ntxiv txog kev ntsuas tuaj yeem pom nyob rau hauv kev tshawb fawb dhau los.Tom qab kawm tag nrho cov txiaj ntsig hluav taws xob (TEY) kev kuaj pom thiab nws daim ntawv thov hauv X-PEEM49, qhov kev sim qhov tob ntawm txoj kev no yog kwv yees li 4-5 nm rau Cr teeb liab thiab txog 6 nm rau Fe.Cr qhov tob yog ze heev rau lub thickness ntawm oxide zaj duab xis (~ 4 nm) 60,61 thaum lub Fe qhov tob yog loj dua lub thickness.XRD sau ntawm ntug ntawm Fe L yog sib xyaw ntawm XRD ntawm hlau oxides thiab Fe0 los ntawm matrix.Nyob rau hauv thawj rooj plaub, qhov kev siv ntawm cov emitted electrons los ntawm tag nrho cov muaj peev xwm ntawm electrons uas ua rau TEY.Txawm li cas los xij, lub teeb liab hlau ntshiab yuav tsum muaj zog kinetic ntau dua rau cov hluav taws xob kom dhau los ntawm cov txheej txheem oxide mus rau saum npoo thiab raug sau los ntawm tus ntsuas.Hauv qhov no, Fe0 teeb liab feem ntau yog vim LVV Auger electrons, nrog rau cov hluav taws xob theem nrab tawm los ntawm lawv.Tsis tas li ntawd, TEY kev siv zog tau pab los ntawm cov electrons decays thaum lub sij hawm electron khiav txoj kev, ntxiv txo cov Fe0 spectral teb nyob rau hauv lub hlau XAS daim ntawv qhia.
Kev sib xyaw cov ntaub ntawv mining rau hauv cov ntaub ntawv lub voos xwmfab (X-PEEM cov ntaub ntawv) yog ib kauj ruam tseem ceeb hauv kev rho tawm cov ntaub ntawv ntsig txog (tshuaj lom neeg lossis lub cev khoom) hauv ntau txoj hauv kev.K-txhais tau hais tias kev sib koom ua ke tau siv dav hauv ntau qhov chaw, suav nrog kev pom lub tshuab, ua cov duab, tsis muaj kev saib xyuas tus qauv paub, kev txawj ntse txawj ntse, thiab kev txheeb xyuas cais.Piv txwv li, K-txhais tau hais tias kev sib koom ua ke tau ua tau zoo hauv cov ntaub ntawv duab hyperspectral.Hauv cov ntsiab lus, rau cov ntaub ntawv ntau yam, K-txhais tau tias algorithm tuaj yeem yooj yim pab pawg raws li cov ntaub ntawv hais txog lawv cov cwj pwm (photon zog zog).K-txhais tau hais tias pawg yog ib qho algorithm rau kev faib cov ntaub ntawv rau hauv K tsis sib tshooj pawg (pawg), qhov twg txhua pixel belongs rau ib pawg tshwj xeeb nyob ntawm qhov chaw faib khoom ntawm cov tshuaj inhomogeneity hauv steel microstructural muaj pes tsawg leeg.K-txhais tau hais tias algorithm suav nrog ob theem: hauv thawj theem, K centroids raug xam, thiab nyob rau theem thib ob, txhua lub ntsiab lus tau muab ib pawg nrog cov neeg nyob sib ze.Qhov nruab nrab ntawm lub ntiajteb txawj nqus ntawm pawg yog txhais raws li tus lej lej ntawm cov ntaub ntawv cov ntsiab lus (XAS spectrum) rau pawg ntawd.Muaj ntau qhov kev ncua deb los txhais cov centroids nyob sib ze li Euclidean nrug.Rau cov duab input ntawm px, y (qhov twg x thiab y yog qhov kev daws teeb meem hauv pixels), CK yog qhov nruab nrab ntawm lub ntiajteb txawj nqus ntawm pawg;Cov duab no tuaj yeem muab faib ua pawg (pawg) rau hauv K pawg siv K-means63.Cov kauj ruam kawg ntawm K- txhais tau tias pawg algorithm yog:
Kauj ruam 2. Xam cov tswv cuab ntawm tag nrho cov pixels raws li centroid tam sim no.Piv txwv li, nws yog xam los ntawm Euclidean nrug d ntawm qhov chaw thiab txhua pixel:
Kauj Ruam 3 Muab txhua pixel rau qhov ze tshaj plaws centroid.Tom qab ntawd rov xam cov K centroid txoj haujlwm hauv qab no:
Kauj Ruam 4. Rov ua cov txheej txheem (kev sib npaug (7) thiab (8)) kom txog rau thaum lub centroids converge.Cov txiaj ntsig zoo kawg ntawm pawg muaj kev sib raug zoo nrog qhov kev xaiv zoo tshaj plaws ntawm thawj centroids.Rau PEEM cov ntaub ntawv qauv ntawm cov duab hlau, feem ntau X (x × y × λ) yog lub voos xwmfab ntawm 3D array cov ntaub ntawv, thaum lub x thiab y axes sawv cev rau cov ntaub ntawv spatial (pixel daws teeb meem) thiab λ axis sib haum mus rau photon.zog spectral duab.K-txhais tau hais tias algorithm yog siv los tshawb txog cov cheeb tsam txaus siab hauv X-PEEM cov ntaub ntawv los ntawm kev sib cais pixels (pawg lossis sub-blocks) raws li lawv cov spectral nta thiab rho tawm qhov zoo tshaj plaws centroids (XAS spectral profiles) rau txhua qhov kev ntsuas.pawg).Nws yog siv los kawm txog spatial faib, cov kev hloov hauv zos spectral, tus cwj pwm oxidation, thiab tshuaj lom neeg lub xeev.Piv txwv li, K-txhais tau hais tias pawg algorithm tau siv rau Fe L-edge thiab Cr L-edge cheeb tsam nyob rau hauv kub-ua hauj lwm thiab txias-dov X-PEEM.Ntau tus lej ntawm K pawg (cov cheeb tsam ntawm microstructure) tau sim kom pom cov pawg zoo tshaj plaws thiab cov centroids.Thaum cov lej no tau tshwm sim, cov pixels tau muab rov qab rau cov pawg centroids sib thooj.Txhua qhov kev faib xim sib raug rau qhov nruab nrab ntawm pawg, uas qhia txog qhov chaw ntawm cov khoom siv tshuaj lom neeg lossis lub cev.Cov centroids muab rho tawm yog cov kab sib txuas ntawm cov ntshiab spectra.
Cov ntaub ntawv txhawb nqa cov txiaj ntsig ntawm txoj kev tshawb fawb no muaj nyob ntawm qhov kev thov tsim nyog los ntawm tus kws sau WC.
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