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Intsimbi engagqwaliyo esetyenziswa kakhulu kunye neenguqulelo zayo ezenziweyo ziyamelana nokugqwala kwiimeko ezingqongileyo ngenxa yomaleko wokungashukumi oquka i-chromium oxide. Ukugqwala kunye nokukhukuliseka kwentsimbi kudla ngokunxulunyaniswa nokutshatyalaliswa kwezi layers, kodwa kunqabile ngokubonakala kokungalingani komphezulu, kuxhomekeke kwinqanaba le-microscopic. Kulo msebenzi, i-nanoscale chemical surface heterogeneity, efunyenwe yi-spectroscopic microscopy kunye nohlalutyo lwe-chemometric, ngokungalindelekanga ilawula ukwaphuka kunye nokugqwala kwe-cold rolled cerium modified super duplex stainless steel 2507 (SDSS) ngexesha lokuguqulwa kwayo okushushu. Nangona i-X-ray photoelectron microscopy ibonise ukugubungela okufanayo komaleko wendalo we-Cr2O3, ukusebenza kokungashukumi kwe-cold rolled SDSS bekungalunganga ngenxa yokusasazwa kwendawo kwe-nanoislands ze-Fe3+ ezityebileyo kumaleko we-oxide we-Fe/Cr. Olu lwazi lwesikali se-atom lubonelela ngokuqonda okunzulu kokugqwala kwentsimbi engagqwaliyo kwaye kulindeleke ukuba kuncede ekulweni nokugqwala kweentsimbi ezifanayo ezine-alloy ephezulu.
Ukususela oko kwaveliswa intsimbi engagqwaliyo, iimpawu zokulwa nokugqwala ze-ferrochrome ziye zabangelwa yi-chromium, eyenza ii-oxides/oxyhydroxides ezinamandla kwaye zibonisa ukuziphatha okungenamsebenzi kwiindawo ezininzi. Xa kuthelekiswa neentsimbi ezingagqwaliyo zesiqhelo (i-austenitic kunye ne-ferritic) 1, 2, 3, iintsimbi ezingagqwaliyo ze-super duplex (SDSS) zinokumelana nokugqwala okungcono kunye neempawu ezintle zoomatshini. Amandla okonyuka koomatshini avumela uyilo olukhaphukhaphu noluncinci ngakumbi. Ngokwahlukileyo koko, i-SDSS enoqoqosho inokumelana okuphezulu nokugqwala kwemigodi kunye nokuqhekeka, okubangela ubomi benkonzo obude, ngaloo ndlela yandisa ukusetyenziswa kwayo kulawulo longcoliseko, izikhongozeli zeekhemikhali, kunye nomzi-mveliso weoyile negesi ongaselunxwemeni4. Nangona kunjalo, uluhlu oluncinci lwamaqondo obushushu onyango lobushushu kunye nokwenziwa kakubi kuyayithintela indlela ebanzi yokusebenza. Ke ngoko, i-SDSS itshintshiwe ukuphucula ukusebenza okungentla. Umzekelo, ukuguqulwa kweCe kwaziswa kwi-SDSS 2507 (Ce-2507) enomxholo ophezulu we-nitrogen6,7,8. I-rare earth element (Ce) kuxinzelelo olufanelekileyo lwe-0.08 wt.% inefuthe elihle kwiimpawu zoomatshini ze-DSS, kuba iphucula ukucocwa kweenkozo kunye namandla omda weenkozo. Ukumelana nokuguguleka nokubola, amandla okutsalwa kunye namandla okuvelisa, kunye nokusebenza ngobushushu nazo ziyaphucuka9. Inani elikhulu le-nitrogen lingathatha indawo yomxholo we-nickel obizayo, okwenza i-SDSS ibe nexabiso eliphantsi10.
Kutshanje, i-SDSS iye yaguqulwa ngokweplastiki kubushushu obahlukeneyo (i-cryogenic, ibanda kwaye ishushu) ukuze kufezekiswe iipropati ezintle kakhulu zoomatshini6,7,8. Nangona kunjalo, ukumelana nokugqwala okugqwesileyo kwe-SDSS ngenxa yokubakho kwefilimu encinci ye-oxide kumphezulu kuchatshazelwa zizinto ezininzi ezifana nokungafani okukhoyo ngenxa yokubakho kwezigaba ezahlukeneyo ezinemida eyahlukeneyo yeenkozo, iiprecipitates ezingafunekiyo kunye nempendulo eyahlukileyo.7. Ke ngoko, uphononongo lweepropati ze-microscopic domain zeefilimu ezinjalo ukuya kwinqanaba lesakhiwo se-elektroniki luba lubalulekileyo ekuqondeni ukugqwala kwe-SDSS kwaye lufuna iindlela ezintsonkothileyo zovavanyo. Ukuza kuthi ga ngoku, iindlela ezinobuthathaka kumphezulu ezifana ne-Auger electron spectroscopy11 kunye ne-X-ray photoelectron spectroscopy12,13,14,15 kunye ne-X-ray photoemission microscopy eqinileyo (HAX-PEEM)16 ngokubanzi ziye zasilela ukubona umahluko weekhemikhali kwiimeko zeekhemikhali zomphezulu. iimeko zeekhemikhali zento efanayo kwiindawo ezahlukeneyo zesithuba se-nanoscale. Izifundo ezininzi zakutshanje zidibanise i-oxidation ye-chromium yendawo kunye nokuziphatha kokugqwala okubonweyo kweentsimbi ezingagqwaliyo ze-austenitic17, iintsimbi ze-martensitic18 kunye ne-SDSS19,20. Nangona kunjalo, ezi zifundo zigxile kakhulu kwisiphumo se-Cr heterogeneity (umz., imeko ye-oxidation ye-Cr3+) ekuchaseni ukugqwala. Ukungafani kwe-lateral kwiimeko ze-oxidation zezinto kunokubangelwa ziikhompawundi ezahlukeneyo ezinee-elements ezifanayo, ezifana nee-iron oxides. Ezi khompawundi, ezizuze ubungakanani obuncinci ngenxa yonyango lwe-thermomechanical, zisondelelene, kodwa zahlukile kwi-composition kunye ne-oxidation state16,21. Ke ngoko, ukuze kufunyanwe ukuqhekeka kweefilimu ze-oxide kunye ne-pitting elandelayo, kuyimfuneko ukuqonda ukungafani komphezulu kwinqanaba le-microscopic. Ngaphandle kwezi mfuno, uqikelelo lobungakanani olufana nokungafani kwe-lateral kwi-oxidation, ngakumbi kwi-Fe kwisikali se-nano- kunye ne-atomic, lusanqongophala, kwaye ulwalamano lwayo nokumelana nokugqwala alukahlolwa. Kude kube kutshanje, imeko yeekhemikhali yezinto ezahlukeneyo, ezifana neFe kunye neCa22, kwiisampuli zentsimbi yayichazwa ngokwenani kusetyenziswa i-soft X-ray photoelectron microscopy (X-PEEM) kwizixhobo zemitha ye-synchrotron ye-nanoscale. Idityaniswe ne-chemically sensitive X-ray absorption spectroscopy (XAS), i-X-PEEM ivumela ukulinganiswa kwe-XAS ngesisombululo esiphezulu sendawo kunye ne-spectral, inika ulwazi lweekhemikhali malunga nokwakheka kwezinto kunye nemeko yazo yeekhemikhali ngesisombululo sendawo ukuya kuthi ga kwisikali se-nanometer esingamashumi amabini anesithathu. . Olu qwalaselo lwe-spectromicroscopic lokuqalisa lunceda uqwalaselo lweekhemikhali zasekuhlaleni kwaye lunokubonisa utshintsho lweekhemikhali kwindawo yomaleko wesinyithi olungakhange luphandwe ngaphambili.
Olu phononongo lwandisa iingenelo ze-PEEM ekufumaneni umahluko kwiikhemikhali kwi-nanoscale kwaye lubonisa indlela yohlalutyo lomphezulu we-atomic eqondakalayo yokuqonda ukuziphatha kokugqwala kwe-Ce-2507. Isebenzisa indlela ye-K-means24 chemometric edibeneyo ukumakisha ukufana kweekhemikhali zehlabathi (hetero) zezinto ezibandakanyekayo, ezimeko zazo zeekhemikhali ziboniswe kwisimo sezibalo. Ngokungafaniyo nokugqwala okuqalwe kukutshatyalaliswa kwefilimu ye-chromium oxide kwimeko yendabuko, ukungasebenzi kakuhle kunye nokumelana nokugqwala okuphantsi okwangoku kubangelwa ziziqithi ze-nanoislands ze-Fe3+ ezityebileyo kufutshane nomaleko we-oxide we-Fe/Cr, ezinokuba ziimpawu zokukhusela. I-oxide itshabalalisa ifilimu enamachaphaza kwaye ibangele ukugqwala.
Ukuziphatha okukonakalisayo kwe-SDSS 2507 ekhubazekileyo kwaqala kwavavanywa kusetyenziswa imilinganiselo ye-electrochemical. Kumfanekiso 1 ubonisa ii-curves ze-Nyquist kunye ne-Bode zeesampuli ezikhethiweyo kwisisombululo samanzi esi-acid (pH = 1) se-FeCl3 kubushushu begumbi. I-electrolyte ekhethiweyo isebenza njenge-arhente enamandla ye-oxidizing, ebonisa ukuthambekela kwefilimu yokuchithakala. Nangona izinto zingakhange zidlule kwi-pitting ezinzileyo kubushushu begumbi, uhlalutyo lubonelele ngeziganeko zokungaphumeleli ezinokwenzeka kunye nokugqwala okulandelayo. Isekethe elinganayo (Umfanekiso 1d) yasetyenziselwa ukulingana ne-spectroscopy ye-electrochemical impedance (EIS), kwaye iziphumo zokulingana ezifanelekileyo ziboniswe kwiTheyibhile 1. Ii-semicircles ezingaphelelanga zibonakala kwiisampuli eziphathwe ngesisombululo kunye nezishushu, ngelixa ii-semicircles ezixineneyo zivela kwii-counterparts ezigoqiweyo ezibandayo (Umfanekiso .1b). Kwi-spectroscopy ye-EIS, i-radius ye-semicircle ingathathwa njenge-polarization resistance (Rp)25,26. I-Rp yendlela yeenqwelo moya ecociweyo kwiTheyibhile 1 imalunga ne-135 kΩ cm–2, nangona kunjalo, amaxabiso endlela yeenqwelo moya esebenza ngobushushu kunye ne-cold-rolled aphantsi kakhulu, i-34.7 kunye ne-2.1 kΩ cm–2, ngokwahlukeneyo. Oku kuncipha okubalulekileyo kwi-Rp kubonisa isiphumo esibi sokuguqulwa kweplastiki kwi-passivation kunye nokumelana nokugqwala, njengoko kubonisiwe kwiingxelo zangaphambili27,28,29,30.
a Nyquist, b, c Bode impedance kunye ne-phase diagrams, kunye neemodeli zesekethe ezilinganayo ezihambelanayo d, apho i-RS ilukumelana kwe-electrolyte, i-Rp ilukumelana kwe-polarization, kwaye i-QCPE yi-oxide ye-constant phase element esetyenziselwa ukulinganisa i-non-ideal capacitance (n). Ukulinganiswa kwe-EIS kwenziwa kwi-open circuit potential.
Ii-constants ezihambelanayo ziboniswe kwi-Bode plot, kunye ne-plateau kuluhlu oluphezulu lwee-frequency ezimele ukumelana kwe-electrolyte RS26. Njengoko i-frequency iyancipha, i-impedance iyanda kwaye kufunyenwe i-negative phase angle, ebonisa ukuba i-capacitance dominance inamandla. I-phase angle iyanda, igcina ubuninzi kuluhlu olubanzi lwee-frequency, ize inciphe (Umzobo 1c). Nangona kunjalo, kuzo zonke iimeko ezintathu, olu buninzi lusengaphantsi kwe-90°, lubonisa ukuziphatha okungafanelekanga kwe-capacitive ngenxa yokusabalalisa kwe-capacitive. Ke ngoko, i-QCPE constant phase element (CPE) isetyenziselwa ukumela ukusasazwa kwe-interfacial capacitance okuvela kuburhabaxa bomphezulu okanye ukungalingani, ngakumbi kwisikali se-atomic, i-fractal geometry, i-electrode porosity, i-non-uniform potential, kunye ne-geometry enesimo se-electrodes31,32. I-CPE impedance:
apho u-j linani elicingelwayo kwaye u-ω liyi-angular frequency. I-QCPE yi-frequency independent constant ehambelana nendawo evulekileyo esebenzayo ye-electrolyte. I-n linani lamandla elingenamlinganiselo elichaza ukuphambuka kwe-capacitor kwi-capacitance efanelekileyo, oko kukuthi, u-n usondele ku-1, i-CPE isondele kakhulu kwi-capacitive kuphela, ngelixa ukuba u-n usondele ku-zero, ubonakala echasene. Ukuphambuka okuncinci kwe-n, kufutshane no-1, kubonisa ukuziphatha okungafanelekanga kwe-capacitive yomphezulu emva kovavanyo lwe-polarization. I-QCPE ye-SDSS eqhotsiweyo ebandayo iphezulu kakhulu kunezinye zayo, oko kuthetha ukuba umgangatho womphezulu awufani kangako.
Ngokuhambelana neempawu ezininzi zokumelana nokugqwala kweentsimbi ezingenanto, umxholo ophezulu we-Cr we-SDSS ngokubanzi uphumela ekuchaseni okugqwesileyo kokugqwala kwe-SDSS ngenxa yokubakho kwefilimu ye-oxide ekhuselayo edlulayo kumphezulu17. Iifilimu ezinjalo zokugqwala zihlala zizityebi kwi-Cr3+ oxides kunye/okanye ii-hydroxides, ikakhulu xa zidibene ne-Fe2+, Fe3+ oxides kunye/okanye (oxy) hydroxides33. Nangona umphezulu ofanayo ufana, umaleko we-oxide edlulayo, kwaye akukho kuqhekeka komphezulu okubonwayo ngokwemilinganiselo ye-microscopic6,7, ukuziphatha kokugqwala kwe-SDSS esebenza ngobushushu kunye ne-cold-rolled kwahlukile, ngoko ke uphando olunzulu lweempawu ze-microstructure luyimfuneko ukuze kuguqulwe intsimbi.
Ulwakhiwo lwe-microstructure yentsimbi engagqwaliyo eguqulweyo lufundwe ngokwenani kusetyenziswa ii-X-rays zangaphakathi kunye nee-synchrotron ezinamandla aphezulu (Imifanekiso eyongezelelweyo 1, 2). Uhlalutyo oluneenkcukacha lubonelelwe kwiNkcukacha eyoNgezelelweyo. Nangona kukho ukuvumelana ngokubanzi ngohlobo lwesigaba esikhulu, umahluko kwiinxalenye zesigaba esikhulu ufunyenwe, ezidweliswe kwiTheyibhile eyoNgezelelweyo 1. Olu mahluko lunokubangelwa ziinxalenye zesigaba ezingalinganiyo kumphezulu nakwivolumu, ezichaphazeleka bubunzulu obahlukeneyo bokufumanisa i-X-ray diffraction (XRD). ) kunye nemithombo eyahlukeneyo yamandla ye-incident photons34. Iinxalenye ze-austenite eziphezulu ngokwentelekiso kwiisampuli ezigoqiweyo ezibandayo ezimiselwe yi-XRD evela kumthombo webhubhoratri zibonisa ukudlula okungcono kunye nokumelana nokugqwala okungcono35, ngelixa iziphumo ezichanekileyo nezineenkcukacha zibonisa iindlela ezichaseneyo kwiinxalenye zesigaba. Ukongeza, ukumelana nokugqwala kwentsimbi kuxhomekeke kwinqanaba lokucocwa kweenkozo, ukunciphisa ubungakanani beenkozo, ukwanda kwe-microdeformations kunye noxinano lwe-dislocation olwenzeka ngexesha lonyango lwe-thermomechanical36,37,38. Iisampuli ezishushu zibonise uhlobo olunezinti, olubonisa iinkozo ezinobukhulu be-micron, ngelixa iiringi ezigudileyo ezibonwe kwiisampuli ezigoqwe ngokubandayo (Umzobo Ongezelelweyo 3) zibonisa ukucocwa okubalulekileyo kweenkozo ukuya kwi-nanosize kumsebenzi wangaphambili. Oku kufanele kukhuthaze ukwakheka kwefilimu engasebenziyo kunye nokwanda kokumelana nokugqwala. Uxinano oluphezulu lwe-dislocation ludla ngokunxulunyaniswa nokumelana okuphantsi kwi-pitting, okuhambelana kakuhle nomlinganiselo we-electrochemical.
Utshintsho kwimeko yeekhemikhali ze-microdomains zezinto eziphambili lufundwe ngokucwangcisiweyo kusetyenziswa i-X-PEEM. Nangona kukho ezinye izinto ezidibanisayo, i-Cr, i-Fe, i-Ni kunye ne-Ce39 zikhethwe apha, ekubeni i-Cr yeyona nto iphambili yokwenza ifilimu engasebenziyo, i-Fe yeyona nto iphambili yentsimbi, kwaye i-Ni iphucula i-passivation kwaye ilinganisela isigaba se-ferrite-austenitic. Ulwakhiwo kunye nokuguqulwa yinjongo ye-Ce. Ngokulungisa amandla e-synchrotron beam, i-XAS ibambe iimpawu eziphambili ze-Cr (L2.3 edge), i-Fe (L2.3 edge), i-Ni (L2.3 edge), kunye ne-Ce (M4.5 edge) ukusuka kumphezulu. -2507 SDSS. Uhlalutyo lwedatha olufanelekileyo lwenziwe ngokubandakanya ukulinganiswa kwamandla ngedatha epapashweyo (umz. i-XAS kwi-Fe L2, i-3 ribs40,41).
Kumfanekiso 2 ubonisa imifanekiso ye-X-PEEM ye-hot-worked (Umfanekiso 2a) kunye ne-cold-rolled (Umfanekiso 2d) Ce-2507 SDSS kunye ne-XAS Cr kunye ne-Fe L2,3 edges ezihambelanayo kwiindawo eziphawulwe ngokwahlukeneyo. Umphetho we-L2,3 XAS uhlola imeko ze-3d ezingenamntu zee-electrons emva kokuvezwa kwe-photo kumanqanaba okwahlulahlula i-spin-orbit ye-2p3/2 (L3 edge) kunye ne-2p1/2 (L2 edge). Ulwazi malunga nemeko ye-valence ye-Cr lufunyenwe kuhlalutyo lwe-X-ray diffraction lomphetho we-L2,3 kuMfanekiso 2b,d. Uthelekiso lwekhonkco. 42, 43 lubonise ukuba iincopho ezine ze-A (578.3 eV), B (579.5 eV), C (580.4 eV), kunye ne-D (582.2 eV) zibonwe kufutshane nomphetho we-L3, zibonakalisa i-octahedral Cr3+ ions, i-Cr2O3 ehambelanayo. Iispectra zovavanyo ziyavumelana nezibalo zethiyori, njengoko kubonisiwe kwiiphaneli b kunye no-e, ezifunyenwe kwiibalo ezininzi zentsimi yekristale kwi-interface yeCr L2.3 kusetyenziswa intsimi yekristale ye-2.0 eV44. Zombini iindawo ze-SDSS ezisebenza ngobushushu kunye neziqengqelekayo ezibandayo zigqunywe ngomaleko ofanayo weCr2O3.
Umfanekiso oshushu we-X-PEEM SDSS eyenziwe ngobushushu ohambelana nomphetho b Cr L2.3 kunye nomphetho c Fe L2.3, d Umfanekiso oshushu X-PEEM we-SDSS eqengqelekayo ebandayo ohambelana nomphetho e Cr L2.3 kunye f Fe L2.3 wecala (e). Ii-spectra ze-XAS ezidwetshwe kwiindawo ezahlukeneyo zesithuba eziphawulwe kwimifanekiso yobushushu (a, d) yimigca e-orenji enamachaphaza ku-(b) kunye (e) zimele ii-spectra ze-XAS ezilinganisiweyo ze-Cr3+ ngexabiso le-crystal field le-2.0 eV. Kwimifanekiso ye-X-PEEM, i-palette yobushushu isetyenziselwa ukuphucula ukufundeka komfanekiso, apho imibala ukusuka kuluhlaza okwesibhakabhaka ukuya kubomvu ihambelana nobukhulu bokufunxwa kwe-X-ray (ukusuka ezantsi ukuya phezulu).
Nokuba imeko-bume yeekhemikhali zezi zinto zesinyithi injani na, imeko yeekhemikhali yokongezwa kwezinto ze-Ni kunye ne-Ce kwiisampulu zombini yahlala ifana. Umzobo owongezelelweyo. Kumfanekiso 5-9 bonisa imifanekiso ye-X-PEEM kunye nee-spectra ze-XAS ezihambelanayo ze-Ni kunye ne-Ce kwiindawo ezahlukeneyo kumphezulu weesampuli ezishushu neziqengqelekayo. I-Ni XAS ibonisa imeko ye-oxidation ye-Ni2+ phezu komphezulu wonke olinganisiweyo weesampuli ezishushu neziqengqelekayo (Ingxoxo Eyongezelelekileyo). Kuyaphawuleka ukuba kwimeko yeesampuli ezishushu, isignali ye-XAS ye-Ce ayibonwa, ngelixa i-spectrum ye-Ce3+ yeesampuli eziqengqelekayo ezibandayo ibonwa ngaxesha lithile. Ukubonwa kwamabala e-Ce kwiisampulu eziqhaqhelekayo ezibandayo kubonise ukuba i-Ce ikhona ikakhulu ngohlobo lwe-precipitates.
Kwi-SDSS eguqulwe bubushushu, akukho tshintsho lwesakhiwo sendawo kwi-XAS olubonwe kumda we-Fe L2.3 (Umzobo 2c). Nangona kunjalo, njengoko kubonisiwe kumzobo 2f, i-matrix ye-Fe itshintsha ngokwe-microscope imeko yayo yeekhemikhali kwiindawo ezisixhenxe ezikhethwe ngokungacwangciswanga kwi-SDSS eqhotsiweyo ebandayo. Ukongeza, ukuze kufunyanwe umbono ochanekileyo wotshintsho kwimeko ye-Fe kwiindawo ezikhethiweyo kumzobo 2f, kwenziwe izifundo zomphezulu wendawo (Umzobo 3 kunye nomzobo ongezelelweyo 10) apho kukhethwe khona iindawo ezincinci ezijikelezayo. Ii-spectra ze-XAS zomda we-Fe L2,3 weenkqubo ze-α-Fe2O3 kunye ne-Fe2+ octahedral oxides zenziwe imodeli kusetyenziswa ukubalwa kwe-multiplet crystal field kusetyenziswa amasimi ekristale e-1.0 (Fe2+) kunye ne-1.0 (Fe3+)44. Siqaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zine-symmetries zasekuhlaleni ezahlukeneyo45,46, i-Fe3O4 inomdibaniso we-Fe2+ kunye ne-Fe3+,47, kunye ne-FeO45 njenge-Fe2+ oxide edityanisiweyo ngokusemthethweni (3d6). Siqaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zine-symmetries zasekuhlaleni ezahlukeneyo45,46, i-Fe3O4 inomdibaniso we-Fe2+ kunye ne-Fe3+,47, kunye ne-FeO45 njenge-Fe2+ oxide edityanisiweyo ngokusemthethweni (3d6).Qaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zine-symmetries zasekuhlaleni ezahlukeneyo45,46, i-Fe3O4 idibanisa zombini i-Fe2+ kunye ne-Fe3+,47 kunye ne-FeO45 ngendlela ye-oxide edivalent esemthethweni i-Fe2+ (3d6).Qaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zine-symmetries zasekuhlaleni ezahlukeneyo45,46, i-Fe3O4 ineendibaniselwano ze-Fe2+ kunye ne-Fe3+,47 kwaye i-FeO45 isebenza njenge-oxide ye-Fe2+ esemthethweni (3d6). Zonke ii-ion ze-Fe3+ kwi-α-Fe2O3 zinezikhundla ze-Oh kuphela, ngelixa i-γ-Fe2O3 idla ngokubonakaliswa njenge-Fe3+ t2g [Fe3+5/3V1/3]eg O4 spinel enezithuba kwiindawo umz. Ke ngoko, ii-ion ze-Fe3+ kwi-γ-Fe2O3 zinezikhundla ze-Td kunye ne-Oh. Njengoko bekutshiwo kumsebenzi odlulileyo, nangona umlinganiselo wobunzulu bezi zimbini wahlukile, umlinganiselo wazo wobunzulu umz/t2g yi-≈1, ngelixa kule meko umlinganiselo wobunzulu obonweyo umz/t2g umalunga ne-1. Oku kususa ithuba lokuba kubekho i-Fe3+ kuphela kweli tyala. Xa sijonga imeko yeFe3O4 kunye nendibaniselwano yeFe2+ kunye neFe3+, kuyaziwa ukuba uphawu lokuqala olubuthathaka (olunamandla) kumda we-L3 weFe lubonisa ukungabikho okuncinci (okukhulu) kwimeko ye-t2g. Oku kusebenza kwiFe2+ (Fe3+), ebonisa ukwanda kophawu lokuqala olubonisa ukwanda komxholo weFe2+47. Ezi ziphumo zibonisa ukuba iFe2+ kunye ne-γ-Fe2O3, i-α-Fe2O3 kunye/okanye iFe3O4 zilawula kwiindawo ezibandayo eziqengqelekayo zee-composites.
Imifanekiso ekhulisiweyo ye-photoemission electron thermal ye-(a, c) kunye ne-(b, d) XAS spectra ngaphesheya komda we-Fe L2,3 kwiindawo ezahlukeneyo zesithuba ngaphakathi kwemimandla ekhethiweyo yesi-2 kunye ne-E kwiMifanekiso yesi-2d.
Idatha yovavanyo efunyenweyo (Umzobo 4a kunye noMfanekiso oNcedisayo 11) yadwetshwa yaza yathelekiswa neyeekhompawundi ezimsulwa 40, 41, 48. Ngokusisiseko, iintlobo ezintathu ezahlukeneyo ze-Fe L-edge XAS spectra ebonwe ngovavanyo (XAS-1, XAS-2 kunye ne-XAS-3: Umzobo 4a) zabonwa kwiindawo ezahlukeneyo ngokwendawo. Ngokukodwa, i-spectrum efana ne-2-a (ebizwa ngokuba yi-XAS-1) kwiMfanekiso 3b yabonwa kulo lonke ummandla onomdla, ilandelwa yi-spectrum ye-2-b (ebhalwe nge-XAS-2), ngelixa i-spectrum efana ne-E-3 yabonwa kwiMfanekiso 3d (ebizwa ngokuba yi-XAS-3) yabonwa kwiindawo ezithile ezikufutshane. Ngokwesiqhelo, iiparameter ezine zisetyenziselwa ukuchonga imeko ye-valence ekhoyo kwisampulu ye-probe: (1) iimpawu ze-spectral ze-L3 kunye ne-L2, (2) izikhundla zamandla zeempawu ze-L3 kunye ne-L2, (3) umahluko wamandla e-L3-L2, (4) umlinganiselo wobunzulu be-L2 /L3. Ngokwezinto ezibonwayo (Umzobo 4a), zonke izinto ezintathu ze-Fe, ezizezi i-Fe0, i-Fe2+, kunye ne-Fe3+, zikho kumphezulu we-SDSS efundwayo. Umlinganiselo wokubalwa kobunzulu L2/L3 ukwabonise ukuba zikhona zonke izinto ezintathu.
a Kubonwe idatha ezintathu ezahlukeneyo zovavanyo (imigca eqinileyo i-XAS-1, i-XAS-2 kunye ne-XAS-3 ihambelana ne-2-a, i-2-b kunye ne-E-3 kwiFig. 2 kunye neFig. 3) xa kuthelekiswa ne-XAS elinganisiweyo Iispectra zoQhathaniso, ii-octahedrons i-Fe2+, i-Fe3+, ixabiso le-crystal field ye-1.0 eV kunye ne-1.5 eV, ngokulandelelana, b–d Idatha yovavanyo elinganisiweyo (i-XAS-1, i-XAS-2, i-XAS-3) kunye nedatha ye-LCF ehambelanayo (umgca omnyama oqinileyo), kunye nokuthelekisa ii-XAS-3 spectra kunye ne-Fe3O4 (imeko exutyiweyo ye-Fe) kunye ne-Fe2O3 (i-Fe3+ ecocekileyo).
Ukulingana komgca (LCF) wemigangatho emithathu40,41,48 kusetyenzisiwe ukulinganisa ukwakheka kwe-iron oxide. I-LCF yenziwe kwiispectra ezintathu ze-Fe L-edge XAS ezikhethiweyo ezibonisa umahluko ophezulu, oko kukuthi i-XAS-1, i-XAS-2 kunye ne-XAS-3, njengoko kubonisiwe kwiFig. 4b–d. Kwi-LCF fittings, i-10% Fe0 iqwalaselwe kuzo zonke iimeko ngenxa ye-ledge encinci esiyibonileyo kuyo yonke idatha kunye nenyaniso yokuba i-ferrous metal yeyona nto iphambili yentsimbi. Enyanisweni, ubunzulu bovavanyo lwe-X-PEEM ye-Fe (~6 nm)49 bukhulu kunobukhulu obuqikelelweyo beleyara ye-oxidation (kancinci > 4 nm), okuvumela ukubonwa kwesiginali evela kwi-iron matrix (Fe0) phantsi kweleyara ye-passivation. Enyanisweni, ubunzulu bovavanyo lwe-X-PEEM ye-Fe (~6 nm)49 bukhulu kunobukhulu obuqikelelweyo beleyara ye-oxidation (kancinci > 4 nm), okuvumela ukubonwa kwesiginali evela kwi-iron matrix (Fe0) phantsi kweleyara ye-passivation. Действительно, пробная глубина X-PEEM для Fe (~ 6 нм)49 больше, чем предполагаемая толщина слоя окисления (немного > 4 iintsini), сигнал от железной матрицы (Fe0) под пассивирующим слоем. Enyanisweni, ubunzulu be-probe X-PEEM kwi-Fe (~6 nm)49 bukhulu kunobukhulu obuqikelelweyo beleyara ye-oxidation (kancinci >4 nm), nto leyo eyenza kube nokwenzeka ukubona isignali evela kwi-iron matrix (Fe0) phantsi kweleyara ye-passivation.Enyanisweni, i-X-PEEM ibona i-Fe (~6 nm)49 nzulu kunobukhulu obulindelekileyo bomaleko we-oxide (ngaphezulu nje kwe-4 nm), okuvumela ukubonwa kwemiqondiso evela kwi-iron matrix (Fe0) ngaphantsi komaleko we-passivation. Iindidi ezahlukeneyo ze-Fe2+ kunye ne-Fe3+ zenziwe ukuze kufunyanwe isisombululo esifanelekileyo sedatha yovavanyo ebonweyo. Kumfanekiso. Umfanekiso 4b ubonisa indibaniselwano ye-Fe2+ kunye ne-Fe3+ kwi-XAS-1 spectrum, apho ii-ratio ze-Fe2+ kunye ne-Fe3+ zisondelelene, malunga ne-45%, nto leyo ebonisa imeko ye-oxidation exutyiweyo ye-Fe. Ngelixa kwi-XAS-2 spectrum, ipesenti ye-Fe2+ kunye ne-Fe3+ iba yi-~30% kunye ne-60%, ngokwahlukeneyo. Umxholo we-Fe2+ ungaphantsi kunowe-Fe3+. Umlinganiselo we-Fe2+ ukuya kwi-Fe3 we-1:2 uthetha ukuba i-Fe3O4 inokwakheka ngomlinganiselo ofanayo wee-ion ze-Fe. Ukongeza, kwi-XAS-3 spectrum, iipesenti ze-Fe2+ kunye ne-Fe3+ zitshintshele kwi-~10% kunye ne-80%, nto leyo ebonisa ukuguqulwa okuphezulu kwe-Fe2+ ukuya kwi-Fe3+. Njengoko kukhankanyiwe ngasentla, i-Fe3+ inokuvela kwi-α-Fe2O3, γ-Fe2O3 okanye i-Fe3O4. Ukuze kuqondwe umthombo onokwenzeka we-Fe3+, ii-XAS-3 spectra zidwetshwe kunye nemigangatho eyahlukeneyo ye-Fe3+ kwiFig. 4e ebonisa ukufana nayo yonke imigangatho emibini xa kujongwa iPeak B. Nangona kunjalo, amandla egxalaba (A: ukusuka kwi-Fe2+) kunye nomlinganiselo wobunzulu B/A zibonisa ukuba i-spectrum ye-XAS-3 isondele kodwa ayifani ne-γ-Fe2O3. Xa kuthelekiswa ne-bulk γ-Fe2O3, amandla e-Fe2p XAS encotsheni ye-A SDSS aphezulu kancinci (Fig. 4e), nto leyo ebonisa amandla aphezulu e-Fe2+. Nangona i-spectrum ye-XAS-3 ifana neye-γ-Fe2O3, apho i-Fe3+ ikhona kuzo zombini izikhundla ze-Oh kunye ne-Td, ukuchongwa kweemeko ezahlukeneyo ze-valence kunye nokulungelelaniswa kuphela ngumda we-L2,3 okanye umlinganiselo we-L2/L3 intensity kuseyingxaki. Isihloko esiphindaphindayo sengxoxo ngenxa yobunzima bezinto ezahlukeneyo ezibandakanyekayo kwi-spectrum yokugqibela41.
Ukongeza kucalucalulo lwe-spectral lweemeko zeekhemikhali zemimandla ekhethiweyo enomdla echazwe apha ngasentla, ukungafani kweekhemikhali zehlabathi jikelele kwezinto eziphambili i-Cr kunye ne-Fe kuhlolwe ngokwahlulahlula zonke ii-spectra ze-XAS ezifunyenwe kumphezulu wesampuli kusetyenziswa indlela ye-K-means clustering. Iiprofayili zomphetho i-Cr L zibekwe ngendlela yokuba zenze amaqela amabini afanelekileyo asasazwe ngokwendawo kwiisampuli ezishushu nezibandayo eziboniswe kwiMifanekiso 5. Kuyacaca ukuba akukho tshintsho lwesakhiwo lwendawo olubonwe, kuba ii-centroid ezimbini ze-XAS Cr spectra zifana kakhulu. Ezi mpawu ze-spectral zamaqela amabini ziphantse zifane nezo zihambelana ne-Cr2O342, oko kuthetha ukuba iileya ze-Cr2O3 zisasazwe ngokulinganayo kwi-SDSS.
iqela leengingqi ze-K-means L-edge Cr, ii-centroids ze-XAS ezihambelanayo b. Iziphumo zothelekiso lwe-K-means X-PEEM lwe-SDSS eqhotsiweyo ebandayo: ii-c c c c zeendawo ze-K-means edge ze-Cr L2,3 kunye ne-d ehambelanayo ne-XAS centroids.
Ukubonisa imephu yomphetho we-FeL eyinkimbinkimbi ngakumbi, amaqela amane nantlanu alungiselelweyo kunye nee-centroids zawo ezinxulumene nazo (ukusasazwa kwe-spectral) zisetyenziselwa iisampuli ezishushu neziqengqelekayo, ngokulandelelana. Ke ngoko, ipesenti (%) ye-Fe2+ kunye ne-Fe3+ ingafunyanwa ngokulungisa i-LCF eboniswe kwiFig.4. I-pseudo potential Epseudo njengomsebenzi we-Fe0 yasetyenziswa ukutyhila ukungalingani kwe-microchemical yefilimu ye-oxide yomphezulu. I-Epseudo iqikelelwa ngomgaqo wokuxuba,
apho \(\rm{E}_{\rm{Fe}/\rm{Fe}^{2 + (3 + )}}\) ilingana \(\rm{Fe} + 2e^ – \to\rm {Fe}^{2 + (3 + )}\), eyi-0.440 kunye ne-0.036 V, ngokwahlukeneyo. Iindawo ezinamandla aphantsi zinomxholo ophezulu weekhompawundi zeFe3+. Ukusasazwa kwamandla kwisampulu eguqulwe ngobushushu kunophawu oluneeleya ezinotshintsho olukhulu olumalunga ne-0.119 V (Umzobo 6a,b). Olu sasazo olunokwenzeka lunxulumene kakhulu ne-surface topography (Umzobo 6a). Akukho tshintsho lunxulumene nendawo olubonwe ngaphakathi kwe-lamellar engaphantsi (Umzobo 6b). Ngokuchaseneyo, ngokudityaniswa kwee-oxides ezahlukeneyo kunye nomxholo owahlukileyo weFe2+ kunye neFe3+ kwi-SDSS eqengqelekayo ebandayo, uhlobo olungalinganiyo lwe-pseudopotential lunokubonwa (Umzobo 6c, d). Ii-Fe3+ oxides kunye/okanye ii-oxy hydroxides zezona zinto ziphambili zokubola kwintsimbi kwaye zingena kwioksijini namanzi50. Kule meko, kunokubonwa ukuba iziqithi ezityebileyo kwiFe3+ zisasazeke kwindawo kwaye zinokuthathwa njengeendawo zokubola. Kule meko, i-gradient kwintsimi enokubakho, endaweni yexabiso elipheleleyo le-potential, inokuthathwa njengesalathiso sendawo yeendawo zokubola ezisebenzayo51. Olu sasazo olungafaniyo lweFe2+ kunye neFe3+ kumphezulu we-SDSS eqhotsiweyo ebandayo lunokutshintsha iipropati zeekhemikhali zasekuhlaleni kwaye lubonelele ngendawo esebenza ngakumbi ekuqhekekeni kwefilimu ye-oxide kunye neempendulo zokubola, ngaloo ndlela luvumela i-matrix yesinyithi engaphantsi ukuba iqhubeke nokubola, okubangela ukungomelelani kwangaphakathi. kwaye kunciphise iimpawu zokukhusela zomaleko odlulayo.
Ii-K-mean clusters ze-Fe L2,3 edge regions kunye ne-XAS centroids ezihambelanayo ze-a-c eshushu esebenza nge-X-PEEM kunye ne-d-f cold-rolled SDSS. a, d K-means cluster plot egqunywe kumfanekiso we-X-PEEM. Ii-pseudo potentials eziqikelelweyo (i-epseudo) zikhankanyiwe kunye needayagram ze-K-means cluster. Ukukhanya komfanekiso we-X-PEEM njengombala okwiFig. 2 kuhambelana ngokuthe ngqo nobunzulu bokufunxwa kwe-X-ray.
I-Cr efanayo kodwa imeko eyahlukileyo yekhemikhali ye-Fe ikhokelela kwimvelaphi eyahlukileyo yokuqhekeka kwefilimu ye-oxide kunye neepatheni zokubola kwi-Ce-2507 eqengqelekayo nebandayo. Le propati ye-Ce-2507 eqengqelekayo iyaziwa. Ngokuphathelele ukwakheka kwee-oxide kunye nee-hydroxide ze-Fe emoyeni womoya, ezi mpendulo zilandelayo zivaliwe kulo msebenzi njengeempendulo ezingathathi cala:
Ngokusekelwe ekulinganisweni kwe-X-PEEM, le mpendulo ingasentla yenzeke kwiimeko ezilandelayo. Igxalaba elincinci elihambelana ne-Fe0 linxulunyaniswa nesinyithi sesinyithi esingaphantsi. Impembelelo ye-Fe yesinyithi kunye nokusingqongileyo ikhokelela ekwakhiweni komaleko we-Fe(OH)2 (i-equation (5)), eyandisa isignali ye-Fe2+ kwi-XAS yomda we-L we-Fe. Ukuvezwa ixesha elide emoyeni kuya kubangela ukwakheka kwe-Fe3O4 kunye/okanye ii-Fe2O3 oxides emva kwe-Fe(OH)252,53. Iindidi ezimbini ze-Fe ezizinzileyo, i-Fe3O4 kunye ne-Fe2O3, nazo zinokwenziwa komaleko okhuselayo we-Cr3+ otyebileyo, apho i-Fe3O4 ikhetha isakhiwo esifanayo nesidibeneyo. Ubukho bazo zombini buphumela kwiimeko ezixutyiweyo ze-oxidation (i-XAS-1 spectrum). I-XAS-2 spectrum ihambelana kakhulu ne-Fe3O4. Ngelixa i-XAS-3 spectra ebonwe kwiindawo ezahlukeneyo ibonise ukuguqulwa okupheleleyo kwi-γ-Fe2O3. Ekubeni ii-X-rays ezingasongwanga zinobunzulu bokungena obumalunga nama-50 nm, isignali evela kumaleko angaphantsi ibangela ukuba i-A peak ibe namandla aphezulu.
I-XRD spectrum ibonisa ukuba icandelo le-Fe kwifilimu ye-oxide linesakhiwo esineeleya, esidityaniswe neleya ye-Cr oxide. Ngokungafaniyo neempawu zokungaphazami kokugqwala ngenxa yokungalingani kwendawo ye-Cr2O317, nangona ileya ye-Cr2O3 ifanayo kolu phononongo, ukumelana nokugqwala okuphantsi kwabonwa kule meko, ngakumbi kwiisampuli eziqengqelekayo ezibandayo. Ukuziphatha okubonweyo kunokuqondwa njengokungafani kwemeko ye-chemical oxidation yomaleko ophezulu (Fe) ochaphazela ukusebenza kokugqwala. Ukudluliselwa kancinci kwee-ion zesinyithi okanye ze-oxygen kwi-lattice ngenxa ye-stoichiometry efanayo yomaleko ophezulu (Fe oxide) kunye nomaleko asezantsi (Cr oxide)52,53 kukhokelela ekusebenzisaneni okungcono (ukunamathela) phakathi kwazo. Oku, kuphucula ukumelana nokugqwala. Ke ngoko, i-stoichiometry eqhubekayo, oko kukuthi imeko enye ye-oxidation ye-Fe, ikhethwa kunotshintsho olukhawulezileyo lwe-stoichiometric. I-SDSS eguqulwe ngobushushu inomphezulu ofanayo kunye nomaleko okhuselayo oxineneyo, obonelela ngokumelana nokugqwala okungcono. Nangona kunjalo, kwi-SDSS eqengqelekayo ebandayo, ukubakho kweziqithi ezityebileyo ze-Fe3+ phantsi komaleko okhuselayo kutshabalalisa ukuthembeka komphezulu kwaye kubangele ukubola kwe-galvanic kwe-substrate ekufutshane, okukhokelela ekunciphiseni kwe-Rp (Itheyibhile 1) kwi-EIS spectra kunye nokuchasana kwayo nokubola. Ke ngoko, iziqithi ezisasazeke kwindawo ezizityebi kwi-Fe3+ ngenxa yokubola kweplastiki zichaphazela kakhulu ukusebenza kokuchasana nokubola, nto leyo eyimpumelelo kulo msebenzi. Ke ngoko, olu phononongo lubonisa ii-spectromicrographs zokunciphisa ukuchasana nokubola ngenxa yokubola kweplastiki kweesampuli ze-SDSS ezifundweyo.
Ngaphezu koko, nangona i-rare earth alloying kwi-dual phase steels isebenza ngcono, ukusebenzisana kwale nto yongeziweyo ne-steel matrix nganye ngokwendlela yokuziphatha kwe-corrosion kuhlala kungaqondakali ngokusekelwe kwi-spectroscopic microscopy observations. I-Ce signal (ecaleni kwe-XAS M-edge) ibonakala kwiindawo ezimbalwa kuphela ngexesha lokuqengqeleka okubandayo, kodwa iyanyamalala ngexesha lokuguqulwa okushushu kwe-SDSS, nto leyo ebonisa ukufakwa kwe-Ce kwindawo ye-steel matrix endaweni ye-homogeneous alloying. Nangona iipropati ze-mechanical ze-SDSS zingaphuculwa6,7, ubukho be-REE bunciphisa ubungakanani bezinto ezifakiweyo kwaye kucingelwa ukuba bucinezela i-pitting kwindawo yokuqala54.
Ukuqukumbela, lo msebenzi utyhila isiphumo sokungafani komphezulu kwi-corrosion ye-2507 SDSS eguqulwe nge-cerium ngokulinganisa umxholo weekhemikhali zezinto ze-nanoscale. Siphendule umbuzo wokuba kutheni intsimbi engagqwaliyo ibola nokuba igqunywe ngomaleko we-oxide okhuselayo ngokufunda ngokwenani isakhiwo se-microstructure, imeko yeekhemikhali yeempawu zomphezulu kunye nokucutshungulwa kwemiqondiso kusetyenziswa i-K-means clustering. Kuye kwafunyaniswa ukuba iziqithi ezityebileyo ze-Fe3+, kuquka ukulungelelaniswa kwazo kwe-octahedral kunye ne-tetrahedral kulo lonke ulwakhiwo lwe-mixed Fe2+/Fe3+, zingumthombo wokutshatyalaliswa kwefilimu ye-oxide kunye nomthombo wokubola kwe-cold-rolled SDSS. Iziqithi ze-Nanoislands ezilawulwa yi-Fe3+ zikhokelela ekuchaseni okungalunganga kwe-corrosion nokuba kukho umaleko owaneleyo we-stoichiometric Cr2O3 passivating. Ukongeza kwinkqubela phambili yendlela eyenziweyo ekumiseleni isiphumo sokungafani kweekhemikhali ze-nanoscale kwi-corrosion, umsebenzi wangoku kulindeleke ukuba ukhuthaze iinkqubo zobunjineli ukuphucula ukuxhathisa kwe-corrosion kweentsimbi ezingagqwaliyo ngexesha lokwenza intsimbi.
Ukulungiselela ii-ingot ze-Ce-2507 SDSS ezisetyenzisiweyo kolu phononongo, izinto ezixutyiweyo, kuquka i-Fe-Ce master alloy evalwe ngeetyhubhu zesinyithi ezicocekileyo, zanyibilikiswa kwisithando somlilo esiphakathi esingama-150 kg ukuvelisa intsimbi enyibilikisiweyo zaza zagalelwa kwiimolds zokubumba. Iikhemikhali ezilinganisiweyo (wt %) zidweliswe kwiTheyibhile eyoNgezelelweyo 2. I-ingot iqala yenziwe ibe ziibhloko. Emva koko intsimbi yafakwa kwi-1050°C imizuzu engama-60 kwisisombululo esiqinileyo, yaze yacinywa emanzini ukuya kubushushu begumbi. Iisampulu ezifundiweyo zafundwa ngokweenkcukacha kusetyenziswa i-TEM kunye ne-DOE ukufunda izigaba, ubungakanani bengqolowa kunye nemofoloji. Ulwazi oluthe kratya malunga neesampulu kunye nenkqubo yemveliso lunokufumaneka kweminye imithombo6,7.
Iisampulu ze-cylindrical (φ10 mm × 15 mm) zokucinezela ngobushushu kunye ne-axis yesilinda ehambelana necala lokuguquka kwebhloko. Uxinzelelo lobushushu obuphezulu lwenziwa ngesantya soxinzelelo esingaguqukiyo kuluhlu lwe-0.01-10 s-1 kumaqondo obushushu ahlukeneyo kuluhlu lwe-1000-1150°C kusetyenziswa i-Gleeble-3800 thermal simulator. Ngaphambi kokuguquka, iisampulu zazifudunyezwa kubushushu obukhethiweyo ngesantya se-10 °C s-1 imizuzu emi-2 ukuze kususwe i-gradient yobushushu. Emva kokufikelela kufana kobushushu, iisampulu zaguqulwa zaba yixabiso lokwenyani loxinzelelo lwe-0.7. Emva kokuguquka, zicinywa ngoko nangoko ngamanzi ukugcina isakhiwo esiguqukileyo. Emva koko iisampulu eziqinileyo zanqunyulwa ngokuhambelana necala loxinzelelo. Kolu phononongo luthile, sikhethe isampulu eguqukileyo ngobushushu kwi-1050°C, 10 s-1 ngenxa yobunzima obuphezulu obubonwayo kunezinye iisampulu7.
Iisampulu zobuninzi (80 × 10 × 17 mm3) zesisombululo esiqinileyo seCe-2507 zivavanyiwe kumatshini we-LG-300 onezigaba ezintathu ongangqamanisiyo, oneeroli ezimbini, obonelele ngeempawu ezilungileyo zoomatshini phakathi kwazo zonke ezinye iindidi ze-deformation6. Izinga loxinzelelo kunye nokunciphisa ubukhulu bezinto yayiyi-0.2 m·s-1 kunye ne-5% kwindlela nganye, ngokwahlukeneyo.
I-Autolab PGSTAT128N electrochemical workstation yasetyenziselwa ukulinganisa i-SDSS nge-electrochemical emva kokuqengqeleka okubandayo ukuya kutsho ekunciphiseni ubukhulu be-90% (uxinzelelo olulinganayo lwe-1.0) kunye nokucinezela okushushu ukuya kuxinzelelo oluyinyani lwe-0.7 kwi-1050 oC kunye ne-10 s-1. I-workstation ineseli ye-electrode ezintathu ene-electrode ye-calomel egcweleyo njenge-electrode yesalathiso, i-graphite counter electrode, kunye nesampuli ye-SDSS njenge-electrode esebenzayo. Iisampuli zanqunyulwa zaba zii-cylinders ezinobubanzi be-11.3 mm, emacaleni apho iingcingo zobhedu zadityaniswa khona. Emva koko isampuli yagalelwa nge-epoxy resin, ishiya indawo evulekileyo yokusebenza ye-1 cm2 njenge-electrode yokusebenza (umphezulu ongezantsi wesampuli ye-cylindrical). Lumka ngexesha lokucoca i-epoxy nangexesha lokusila nokupolisha okulandelayo ukuze uphephe ukuqhekeka. Umphezulu wokusebenza ugoqwe kwaye upholishwe nge-diamond polishing suspension enobukhulu be-particle ye-1 micron, icocwe ngamanzi acocekileyo kunye ne-ethanol kwaye yomiswe emoyeni obandayo. Ngaphambi kokulinganisa i-electrochemical, iisampuli ezipholisiweyo zazivezwa emoyeni kangangeentsuku ezininzi ukuze zenze ifilimu ye-oxide yendalo. Isisombululo samanzi se-FeCl3 (6.0 wt.%), esizinziswe nge-HCl ukuya kwi-pH = 1.0 ± 0.01, sisetyenzisiwe ukukhawulezisa ukugqwala kwentsimbi engagqwali55, kuba ifumaneka kwiindawo ezinoburhalarhume apho ii-ion ze-chloride zikhona ngamandla aqinileyo okuxilisa kunye ne-pH ephantsi njengoko kuchaziwe yi-ASTM. Imigangatho ecetywayo yi-G48 kunye ne-A923. Iisampulu zacwiliswa kwisisombululo sovavanyo kangangeyure e-1 ngaphambi kokuba kuthathwe naluphi na umlinganiselo ukuze kufikwe kwimeko ekufutshane ne-statical. Kwisisombululo esiqinileyo, iisampuli ezishushu neziqengqelekayo, uluhlu lwemvamisa yokulinganisa impedance yayiyi-1 × 105 ~ 0.1 Hz, kwaye i-open-circuit potential (OPS) yayiyi-5 mV, eyayiyi-0.39, 0.33, kunye ne-0.25 VSCE, ngokwahlukeneyo. Uvavanyo ngalunye lwe-electrochemical lwalo naliphi na isampuli luphindwe ubuncinane kathathu phantsi kweemeko ezifanayo ukuqinisekisa ukuphinda idatha ivele.
Kwimilinganiselo ye-HE-SXRD, iibhloko zentsimbi eziziingxande eziphindwe kabini eziyi-1 × 1 × 1.5 mm3 zilinganiswe kumgca we-Brockhouse wiggler onamandla aphezulu e-CLS, eKhanada ukuze kulinganiswe ukwakheka kwesigaba56. Ukuqokelelwa kwedatha kwenziwe kubushushu begumbi kwi-geometry yeDebye-Scherrer okanye i-geometry yothutho. Ububanzi be-X-rays obulinganiswe kwi-calibrant yeLaB6 yi-0.212561 Å, ehambelana ne-58 keV, ephezulu kakhulu kuneyeCu Kα (8 keV) esetyenziswa rhoqo njengomthombo we-X-ray webhubhoratri. Isampuli ibekwe kumgama we-740 mm ukusuka kwi-detector. Umthamo wokufumanisa wesampuli nganye yi-0.2 × 0.3 × 1.5 mm3, emiselwa bubungakanani be-beam kunye nobukhulu besampuli. Nganye kwezi datha iqokelelwe kusetyenziswa isixhobo sokubona indawo iPerkin Elmer, isixhobo sokubona i-X-ray esinephaneli ethe tyaba, iiphikseli ezingama-200 µm, i-40 × 40 cm2, kusetyenziswa ixesha lokuvezwa lemizuzwana eyi-0.3 kunye neefreyimu ezili-120.
Ukulinganiswa kwe-X-PEEM kweenkqubo ezimbini zeemodeli ezikhethiweyo kwenziwe kwisikhululo sokugqibela se-PEEM somgca we-Beamline MAXPEEM kwilebhu ye-MAX IV (eLund, eSweden). Iisampulu zalungiswa ngendlela efanayo nokulinganiswa kwe-electrochemical. Iisampulu ezilungisiweyo zagcinwa emoyeni iintsuku ezininzi zaza zakhutshwa igesi kwigumbi le-vacuum elinomoya ophezulu kakhulu ngaphambi kokuba zifakwe i-synchrotron photons. Isisombululo samandla se-beam sifunyanwa ngokulinganisa i-ion output spectrum ukusuka kwi-N 1 s ukuya kwi-1\(\pi _g^ \ast\) yommandla wokukhupha umoya one-hv = 401 eV kwi-N2 kunye nokuxhomekeka kwamandla e-photon kwi-E3/2.57. Ukulingana kwe-Spectral kunike i-ΔE (ububanzi bomgca we-spectral) ~0.3 eV ngaphezulu koluhlu lwamandla olulinganisiweyo. Ngoko ke, isisombululo samandla e-beamline siqikelelwe ukuba yi-E/∆E = 700 eV/0.3 eV > 2000 kwaye i-flux ≈1012 ph/s ngokusebenzisa i-modified SX-700 monochromator ene-Si 1200-line mm−1 grating kwi-Fe 2p L2,3 edge, i-Cr 2p L2,3 edge, i-Ni 2p L2,3 edge, kunye ne-Ce M4,5 edge. Ngoko ke, isisombululo samandla e-beamline siqikelelwe ukuba yi-E/∆E = 700 eV/0.3 eV > 2000 kwaye i-flux ≈1012 ph/s ngokusebenzisa i-modified SX-700 monochromator ene-Si 1200-line mm−1 grating kwi-Fe 2p L2.3 edge, i-Cr 2p L2.3 edge, i-Ni 2p L2.3 edge, kunye ne-Ce M4.5 edge. Таким образом, энергетическое разрешение канала пучка было оценено как E/∆E = 700 эВ/0,3 эВ > 2000 и поток ≈1012 фсы модифицированного монохроматора SX-700 с решеткой Si 1200 штрихов/мм для Fe кромка 2p L2,3, кромка Cr 2p L2,3, кромка Ni 2p L2, 3, кромка Ni 2p L2, 3 Ngoko ke, isisombululo samandla setshaneli yemitha siqikelelwe njenge-E/∆E = 700 eV/0.3 eV > 2000 kwaye i-flux ≈1012 f/s kusetyenziswa i-modified SX-700 monochromator ene-Si grating ye-1200 lines/mm kwi-Fe edge 2p L2 ,3, Cr edge 2p L2.3, Ni edge 2p L2.3, kunye ne-Ce edge M4.5.因此，光束线能量分辨率估计為E/ΔE = 700 eV/0.3 eV > 2000 和通量≈1012 ph/s 1200 线mm−1 光栅用于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 为为為 δe = 700 EV/0.3 EV> 2000 kunye ≈1012 PH/S 通通逕 和改进00 SX 1200 线 mm-1 光栅 于 Fe 2P 2P 2P L2.3 边缘、Cr 2p L2.3 边缘、Ni 2p L2.3 边缘和Ce M4.5 边缘.Ngoko ke, xa usebenzisa i-monochromator ye-SX-700 eguquliweyo kunye ne-1200 line Si grating. 3, i-Cr edge 2p L2.3, i-Ni edge 2p L2.3 kunye ne-Ce edge M4.5.Yandisa amandla e-photon ngamanyathelo e-0.2 eV. Kwi-energy nganye, imifanekiso ye-PEEM irekhodwe kusetyenziswa i-TVIPS F-216 CMOS detector enoqhagamshelwano lwe-fiber optic oluyi-2 x 2 binning olunika ii-pixels eziyi-1024 × 1024 kwindawo yokujonga eyi-20 µm. Ixesha lokuvezwa kwemifanekiso yimizuzwana eyi-0.2, umyinge weefreyimu ezili-16. Amandla omfanekiso we-photoelectron akhethwa ngendlela yokubonelela ngesignali ye-electron yesibini ephezulu. Zonke izilinganiso zenziwa kwisiganeko esiqhelekileyo se-photon beam e-linearly polarized. Ukuze ufumane ulwazi oluthe kratya malunga nemilinganiselo, jonga uphando lwangaphambili58. Emva kokufunda i-total electron yield (TEY)59 detection mode kunye nokusetyenziswa kwayo kwi-X-PEEM, ubunzulu bokufumanisa bale ndlela buqikelelwa kwi ~4–5 nm kwisignali ye-Cr kunye ne ~6 nm kwisignali ye-Fe. Ubunzulu be-Cr busondele kakhulu kubukhulu befilimu ye-oxide (~4 nm)60,61 ngelixa ubunzulu be-Fe bukhulu kunobukhulu befilimu ye-oxide. I-XAS eqokelelwe kufutshane nomphetho we-Fe L ngumxube we-iron oxide XAS kunye ne-FeO evela kwi-matrix. Kwimeko yokuqala, amandla ee-electron ezikhutshiweyo abangelwa zizo zonke iintlobo zee-electron ezinokubakho ezinegalelo kwi-TEY. Nangona kunjalo, isignali yesinyithi esicocekileyo ifuna amandla aphezulu e-kinetic ukuze ii-electron zidlule kumaleko we-oxide, zifikelele kumphezulu, kwaye ziqokelelwe yi-analyzer. Kwimeko enjalo, isignali ye-Fe0 ibangelwa kakhulu zii-electron ze-LVV Auger kunye nee-electron zesibini ezikhutshiweyo zizo. Ukongeza, amandla e-TEY anegalelo kwezi electron abola ngexesha lendlela yokuphuma kwe-electron49 enciphisa ngakumbi uphawu lwe-spectral lwe-Fe0 kwimephu yesinyithi ye-XAS.
Ukudibanisa idatha kwiityhubhu zedatha (idatha ye-X-PEEM) linyathelo elibalulekileyo ekukhupheni ulwazi olufanelekileyo (iikhemikhali okanye iipropati zomzimba) ngendlela enemilinganiselo emininzi. Ukudibanisa i-K-means kusetyenziswa kakhulu kwiindawo ezahlukeneyo, kubandakanya umbono womatshini, ukucutshungulwa komfanekiso, ukuqatshelwa kwepateni engalawulwayo, ubukrelekrele bokwenziwa, kunye nohlalutyo lokwahlulahlula24. Umzekelo, ukuhlanganisa i-K-means kusetyenziswa kakuhle ekuhlanganiseni idatha yomfanekiso we-hyperspectral62. Ngokomgaqo, kwidatha yezinto ezininzi, i-K-means algorithm ingazidibanisa ngokulula ngokweenkcukacha malunga neempawu zazo (iimpawu zamandla e-photon). Ukuhlanganisa i-K-means yi-algorithm ephindaphindayo yokwahlulahlula idatha kumaqela e-K angagqubaniyo (ii-clusters), apho i-pixel nganye ikwiqela elithile ngokuxhomekeke kukusasazwa kwendawo yokungalingani kweekhemikhali kwisakhiwo sesinyithi. I-K-means algorithm inamanyathelo amabini: inyathelo lokuqala libala ii-K centroids, kwaye inyathelo lesibini linika inqaku ngalinye kwiqela elinee-centroids ezikufutshane. Iziko lobunzima bomxhuzulane weqela lichazwa njenge-arithmetic mean yamanqaku edatha (ii-XAS spectra) zelo qela. Kukho imigama eyahlukeneyo yokuchaza ii-centroids ezikufutshane njengemigama ye-Euclidean. Kumfanekiso wokufaka we-px,y (u-x kunye no-y zisisombululo kwii-pixels), i-CK liziko lobunzima bomxhuzulane weqela; lo mfanekiso ungahlulwahlulwa (uhlanganiswe) ube zii-kluster ze-K kusetyenziswa i-K-means63. Amanyathelo okugqibela e-K-means clustering algorithm ngala:
Inyathelo lesi-2. Bala inqanaba lobulungu bazo zonke ii-pixels ngokwe-centroid yangoku. Umzekelo, ibalwa ukusuka kumgama we-Euclidean d phakathi kweziko kunye ne-pixel nganye:
Inyathelo lesi-3 Yabela iphikseli nganye kwi-centroid ekufutshane. Emva koko bala kwakhona izikhundla ze-K centroid ngolu hlobo lulandelayo:
Inyathelo lesi-4. Phinda le nkqubo (ii-equations (7) kunye (8)) ide i-centroids idibane. Iziphumo zomgangatho wokugqibela weqela zihambelana kakhulu nokukhetha okulungileyo kwe-centroids zokuqala63. Kwisakhiwo sedatha ye-PEEM yemifanekiso yentsimbi, ngokuqhelekileyo i-X (x × y × λ) yityhubhu yedatha ye-array ye-3D, ngelixa ii-axes ze-x kunye ne-y zimele ulwazi lwesithuba (isisombululo se-pixel) kwaye i-axis ye-λ ihambelana nemo ye-spectral yamandla yee-photons. I-algorithm ye-K-means yasetyenziswa ukuphonononga imimandla enomdla kwidatha ye-X-PEEM ngokwahlula ii-pixels (ii-clusters okanye ii-sub-blocks) ngokweempawu zazo ze-spectral kunye nokukhupha i-centroid engcono kakhulu (i-XAS spectral curve) kwi-analyte nganye (i-cluster). Isetyenziselwa ukufunda usasazo lwesithuba, utshintsho lwe-spectral yendawo, ukuziphatha kwe-oxidation kunye nemeko yekhemikhali. Umzekelo, i-algorithm ye-K-means clustering yasetyenziselwa i-Fe L-edge kunye ne-Cr L-edge kwimimandla ye-X-PEEM esebenza ngokushushu kunye ne-cold-rolled. Amanani ahlukeneyo ee-K-clusters (iingingqi ze-microstructural) avavanyiwe ukuze kufunyanwe ii-clusters kunye nee-centroids ezilungileyo. Xa igrafu iboniswa, ii-pixels zibuyiselwa kwii-cluster centroids ezichanekileyo. Ukusasazwa kombala ngamnye kuhambelana nombindi we-cluster, okubonisa ulungelelwaniso lwesithuba sezinto zeekhemikhali okanye zezinto ezibonakalayo. Ii-centroids ezikhutshiweyo ziindibaniselwano ezithe ngqo ze-spectra ecocekileyo.
Idatha exhasa iziphumo zolu phando iyafumaneka kumbhali we-WC xa kuceliwe ngokufanelekileyo.
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