Ukutyhila impembelelo yeNanoscale Chemical Inhomogeneity kwiCorrosion of Cerium-Modified 2507 Super Duplex Steel Stainless

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I-stainless steel stainless esetyenziswa ngokubanzi kunye neenguqulelo zayo ezisetyenzisiweyo zixhathisa ukubola kwiimeko eziphantsi ngenxa yomgangatho wokugqithisa owenziwe nge-chromium oxide.I-Corrosion kunye nokuguguleka kwentsimbi ngokuqhelekileyo ihambelana nokutshatyalaliswa kwezi zingqimba, kodwa kunqabile kwinqanaba le-microscopic, kuxhomekeke kwimvelaphi ye-inhomogeneity yomhlaba.Kulo msebenzi, i-nanoscale surface chemical heterogeneity efunyenwe yi-spectroscopic microscopy kunye nohlalutyo lwe-chemometric ngokungalindelekanga ilawula ukubola kunye nokubola kwe-cerium epholileyo epholileyo eguqulelwe i-super duplex stainless steel 2507 (SDSS) ngexesha lokuziphatha kwayo okutshisayo.elinye icala.Nangona i-X-ray photoelectron microscopy ibonise ukugutyungelwa okufanayo komgangatho wendalo we-Cr2O3, i-SDSS eqengqelekayo ebandayo ibonise iziphumo ezibi ngenxa yosasazo lwasekuhlaleni lwe-Fe3+ ye-nanoislands etyebileyo kwi-Fe/Cr oxide layer.Olu lwazi kumgangatho we-athomu lunikeza ukuqonda okunzulu kwi-corrosion yensimbi engenasici kwaye kulindeleke ukuba incede ukulwa nokubola kweentsimbi ezifanayo eziphezulu ze-alloy.
Ukusukela oko kwaveliswa intsimbi engatyiwayo, ukuxhathisa kokutya kwe-ferrochromium alloys kubalelwa kwi-chromium, eyenza i-oksidi eyomeleleyo / i-oxyhydroxide ebonisa ukuziphatha okungahambiyo kwiindawo ezininzi.Xa kuthelekiswa neentsimbi eziqhelekileyo (i-austenitic kunye ne-ferritic) i-stainless steels, i-super duplex stainless steels (SDSS) ene-corrosion resistance resistance ine-property mechanical properties1,2,3.Ukonyuka kwamandla omatshini kuvumela ukuba kube lula kunye noyilo oludibeneyo.Ngokwahlukileyo koko, i-SDSS yezoqoqosho inokumelana okuphezulu nokugrumba kunye ne-corrosion, okukhokelela kubomi benkonzo obude kunye nezicelo ezibanzi kulawulo longcoliseko, izikhongozeli zeekhemikhali, kunye neshishini le-oyile kunye negesi ye-offshore4.Nangona kunjalo, uluhlu olumxinwa lobushushu bonyango lobushushu kunye nokwakheka okungekuhle kuthintela ukusetyenziswa kwayo okubanzi.Ke ngoko, i-SDSS iye yalungiswa ukuze kuphuculwe ezi zakhiwo zingentla.Ngokomzekelo, ukuguqulwa kweCe kunye nokongezwa okuphezulu kwe-N 6, 7, 8 kwaqaliswa kwi-2507 SDSS (Ce-2507).Ugxininiso olufanelekileyo lwe-0.08 wt.% yento yomhlaba enqabileyo (Ce) inempembelelo enenzuzo kwiimpawu zomatshini we-DSS, njengoko iphucula ukucokisa ukutya okuziinkozo kunye nokomelela komda weenkozo.Ukunxiba kunye nokunganyangeki komhlwa, amandla okuqina kunye nokomelela kwesivuno, kunye nokusebenza okushushu nako kuphuculwe9.Izixa ezikhulu zenitrogen zinokuthatha indawo yenickel ebizayo, nto leyo eyenza i-SDSS ingabizi kakhulu10.
Kutshanje, i-SDSS iye yakhubazeka ngokweplastiki kumaqondo obushushu ahlukeneyo (ubushushu obuphantsi, ukubanda nokushushu) ukufezekisa iipropathi ezigqwesileyo zoomatshini6,7,8.Nangona kunjalo, ukuxhathisa okugqwesileyo kokugqwala kwe-SDSS kungenxa yobukho befilimu ye-oxide encinci phezu komhlaba, echatshazelwa zizinto ezininzi, ezinjengobukho bezigaba ezininzi ezinemida yeenkozo ezahlukeneyo, imvula engafunekiyo kunye neempendulo ezahlukeneyo.i-microstructure yangaphakathi ye-inhomogeneous yezigaba ezahlukeneyo ze-austenitic kunye ne-ferritic ikhubazekile 7.Ke ngoko, uphononongo lweepropathi ze-microdomain zezo filimu kwinqanaba lolwakhiwo lwe-elektroniki lubaluleke kakhulu ekuqondeni ukubola kwe-SDSS kwaye kufuna iindlela ezinzima zokulinga.Ukuza kuthi ga ngoku, iindlela ezinobuzaza obuphezulu ezifana ne-Auger electron spectroscopy11 kunye ne-X-ray photoelectron spectroscopy12,13,14,15 kwakunye nenkqubo ye-photoelectron enzima ye-X-ray photoelectron iyahlula, kodwa isoloko isilela ukwahlula, imichiza yeekhemikhali zento enye kumanqaku ahlukeneyo esithubeni kwi-nanoscale.Izifundo ezininzi zamva nje zidibanise i-oxidation yendawo ye-chromium kwi-corrosion behavior ye-17 austenitic stainless steels, i-18 martensitic stainless steels, kunye ne-SDSS 19, 20. Nangona kunjalo, ezi zifundo zijolise kakhulu kwimpembelelo ye-Cr heterogeneity (umz., i-Cr3 + i-oxidrection state).I-Lateral heterogeneity kwi-oxidation state yezinto inokubangelwa yiikhompawundi ezahlukeneyo ezineezakhi ezifanayo, ezifana ne-iron oxides.Ezi khompawundi ilifa a thermomechanically kusetyenzwe ubungakanani encinane ngokusondeleyo kufuphi enye kwenye, kodwa yahluke kukwakheka kunye nemeko oxidation16,21.Ngoko ke, ukutyhila ukutshatyalaliswa kweefilimu ze-oxide kunye nokufaka i-pitting kufuna ukuqonda i-surface inhomogeneity kwinqanaba le-microscopic.Ngaphandle kwezi mfuno, ukuvavanya ubungakanani obufana ne-lateral oxidation heterogeneity, ngokukodwa isinyithi kwisikali se-nano / atomic, sisanqongophala kwaye ukubaluleka kokuchasana kwe-corrosion akubonakali.Kuze kube kutshanje, imeko yeekhemikhali zezinto ezahlukeneyo, ezifana ne-Fe kunye ne-Ca, zichazwe ngokobungakanani kwiisampuli zentsimbi zisebenzisa i-X-ray photoelectron microscopy (X-PEEM) kwizibonelelo ze-nanoscale synchrotron radiation.Idibaniswe ne-X-ray yekhemikhali ye-absorption spectroscopy (XAS) zobugcisa, i-X-PEEM yenza umlinganiselo we-XAS ngesisombululo esiphezulu se-spatial kunye ne-spectral, ukubonelela ngolwazi lwekhemikhali malunga nokubunjwa kwe-elemental kunye nemeko yeekhemikhali kunye nesisombululo sendawo ukuya kwi-nanometer scale 23.Olu qwalaselo lwe-spectroscopic yendawo yokuqaliswa phantsi kwe-microscope iququzelela iimvavanyo zemichiza yendawo kwaye inokubonisa ngokubonakalayo utshintsho lweekhemikhali ezingazange zihlolwe ngaphambili kwi-Fe layer.
Olu pho nonongo lwandisa iingenelo ze-PEEM ekufumaneni ukungafani kweekhemikhali kwi-nanoscale kwaye ibonise indlela yokuhlalutya umgangatho we-athomu ye-athomu yokuqonda indlela yokuziphatha kwe-corrosion ye-Ce-2507.Isebenzisa i-K-ithetha idatha ye-chemometric ye-cluster24 ukwenza imephu yokwakheka kweekhemikhali zehlabathi (i-heterogeneity) yezinto ezibandakanyekayo, kunye neemeko zabo zeekhemikhali ezivezwe kumelo lwamanani.Ngokungafaniyo ne-corrosion eqhelekileyo ebangelwa ukuchithwa kwefilimu ye-chromium oxide, ukungahambi kakuhle kwangoku kunye nokuxhatshazwa okungahambi kakuhle kwe-corrosion kubangelwa iindawo ze-Fe3 + ezityebileyo ze-nanoislands kufuphi ne-Fe / Cr oxide layer, enokuthi ihlaselwe yi-oxide ekhuselayo.Yenza ifilimu endaweni kwaye ibangele umhlwa.
Indlela yokuziphatha eyonakalisayo ye-SDSS 2507 ekhubazekileyo yavavanywa okokuqala kusetyenziswa imilinganiselo ye-electrochemical.Kwikhiwane.Umzobo we-1 ubonisa i-Nyquist kunye ne-Bode curves kwiisampuli ezikhethiweyo kwi-acidic (pH = 1) izixazululo ze-aqueous ze-FeCl3 kwiqondo lokushisa.I-electrolyte ekhethiweyo isebenza njenge-agent eyomeleleyo ye-oxidizing, ebonisa ukuthambekela kwefilimu ye-passivation ukudiliza.Nangona izinto azizange zingene kwi-pitting yeqondo lokushisa elizinzileyo, olu hlalutyo lunike ingqiqo malunga neziganeko ezinokuthi zingaphumeleli kunye neenkqubo zasemva kokubola.Isiphaluka esilinganayo (umzobo we-1d) wasetyenziselwa ukulinganisa i-electrochemical impedance spectroscopy (EIS) spectra, kunye neziphumo ezihambelanayo ezifanelekileyo ziboniswa kwiThebhile 1. Izangqa zesiqingatha ezingaphelelanga zibonakala xa kuhlolwa isisombululo esiphathwayo kunye neesampuli ezishushu ezisebenzayo, ngelixa i-compressed half circles ehambelanayo ifakwe kubanda (Umfanekiso 1b).Kwi-spectrum ye-EIS, i-radius ye-semicircle ingathathwa njengokumelana ne-polarization (Rp) i-25,26.I-Rp yesisombululo iphathwe nge-SDSS kwiThebhile 1 imalunga ne-135 kΩ cm-2, nangona kunjalo kwi-SDSS esebenzayo kunye nebandayo eqengqelekayo sinokubona amaxabiso asezantsi kakhulu angama-34.7 kunye ne-2.1 kΩ cm–2 ngokulandelelanayo.Oku kuncipha okuphawulekayo kwe-Rp kubonisa umphumo onobungozi we-deformation yeplastiki kwi-passivation kunye nokumelana nokubola, njengoko kuboniswe kwiingxelo zangaphambili 27, 28, 29, 30.
i-Nyquist, b, c I-impedance ye-Bode kunye nemizobo yesigaba, kunye nemodeli yesekethe elinganayo ye-d, apho i-RS i-resistance ye-electrolyte, i-Rp yi-resistance polarization, kunye ne-QCPE yinkqubo yesigaba esisisigxina se-oxide esetyenziselwa ukulinganisa i-capacitance engekho kakuhle (n) .Imilinganiselo ye-EIS yaqhutywa ngaphandle komthwalo.
Umyalelo wokuqala ongaguquguqukiyo uboniswa kumzobo weBode kwaye iplateau ephezulu imele ukuxhathisa kwe-electrolyte RS26.Njengoko i-frequency iyancipha, i-impedance iyanda kwaye i-angle yesigaba esibi ifunyenwe, ebonisa ukubusa kwe-capacitance.I-angle yesigaba iyanda, igcina ixabiso layo eliphezulu kuluhlu olubanzi olubanzi, kwaye emva koko iyancipha (Umfanekiso 1c).Nangona kunjalo, kuzo zonke iimeko ezintathu eli xabiso eliphezulu lisengaphantsi kwe-90 °, ebonisa ukuziphatha okungahambi kakuhle kwe-capacitive ngenxa ye-capacitive dispersion.Ngaloo ndlela, i-QCPE yesigaba esisisigxina (CPE) isetyenziselwa ukumela ukusabalalisa i-interfacial capacitance ephuma kwi-roughness okanye i-inhomogeneity, ngokukodwa ngokwemilinganiselo ye-athomu, i-geometry ye-fractal, i-electrode porosity, i-non-uniform potential, kunye nokusabalalisa kwangoku okuxhomekeke kumphezulu.Ijometri ye-electrode31,32.Ukuphazamiseka kweCPE:
apho u-j linani lentelekelelo kwaye ω yi-angular frequency.I-QCPE yindawo ezimeleyo rhoqo ngokulinganayo kwindawo evulekileyo ye-electrolyte.I-n linani lamandla elingenamda elichaza ukutenxa kwindlela efanelekileyo yokuziphatha ye-capacitor, okt i-n esondeleyo ku-1, i-CPE esondeleyo kumandla ococekileyo, kwaye ukuba i-n isondele ku-zero, iyaxhathisa.Ukuphambuka okuncinci kwe-n, kufutshane ne-1, kubonisa ukuziphatha okungahambi kakuhle kwe-capacitive ebusweni emva kovavanyo lwe-polarization.I-QCPE ye-SDSS epholileyo epholileyo iphezulu kakhulu kuneemveliso ezifanayo, oku kuthetha ukuba umgangatho womphezulu awufani.
Ngokuhambelana neendawo ezininzi zokumelana ne-corrosion ye-stainless steels, umxholo we-Cr ophezulu we-SDSS ngokubanzi uphumela ekuxhathiseni okuphezulu kwe-SDSS ngenxa yobukho befilimu ye-oxide ekhuselayo kwi-surface17.Le filimu ehambayo idla ngokutyeba kwi-Cr3 + oxides kunye / okanye i-hydroxides, ngokukodwa idibanisa i-Fe2 +, i-Fe3 + oxides kunye / okanye (i-oxy) i-hydroxides 33.Ngaphandle kokufana komphezulu ofanayo, ukudlula umaleko we-oxide, kwaye akukho monakalo ubonakalayo kumphezulu, njengoko kumiselwe yimifanekiso emikroskopu,6,7 isimilo sokugqwala kwe-SDSS esebenza eshushu kunye nebandayo eqengqelekayo yahlukile kwaye ke ngoko ifuna uphononongo olunzulu lwe-deformation microstructure kunye nesakhiwo sentsimbi.
I-microstructure ye-deformed stainless steel stainless yaphandwa ngokomlinganiselo kusetyenziswa ii-X-rays zangaphakathi kunye ne-synchrotron ezinamandla amakhulu (Amanani abongezelelweyo 1, 2).Uhlalutyo oluneenkcukacha lunikiwe kuLwazi oloNgezelelweyo.Nangona ubukhulu becala zihambelana nohlobo lwesigaba esiphambili, ukungafani kwiinqununu zesigaba somthamo zifunyenwe, ezidweliswe kwi-Supplementary Table 1. Ezi zintlukwano zinokudibaniswa namaqhezu esigaba se-inhomogeneous kwi-surface, kunye ne-volumetric phase fractions eyenziwa kwiindawo ezinzulu ezahlukeneyo.ukufunyanwa nge-X-ray diffraction.(XRD) enemithombo eyahlukeneyo yamandla yeefotoni zesiganeko.Umlinganiselo ophezulu ngokwentelekiso we-austenite kwisampulu eqengqelekisiweyo ebandayo, egqitywe yi-XRD evela kumthombo waselabhoratri, ibonisa ukunyanzelwa ngcono kwaye emva koko i-corrosion resistance35, ngelixa iziphumo ezichaneke ngakumbi kunye nezibalo zibonisa iintsingiselo ezichaseneyo kubungakanani besigaba.Ukongezelela, ukuxhatshazwa kwe-corrosion yensimbi kuxhomekeke kwinqanaba lokucocwa kweenkozo, ukunciphisa ubungakanani beenkozo, ukunyuka kwe-microdeformations kunye nokuxinana kwe-dislocation okwenzeka ngexesha lonyango lwe-thermomechanical36,37,38.Iimpawu ezishushu ezisebenzayo zibonisa ubume obuziinkozo obungaphezulu, obubonisa iinkozo ezinobungakanani be-micron, ngelixa iindandatho ezigudileyo ezibonwa kwimifanekiso epholileyo epholileyo (i-Supplementary Fig. 3) ibonisa ukulungiswa okubonakalayo okuziinkozo kwi-nanoscale kumsebenzi wangaphambili6, okufuneka kube negalelo kwi-passivation yefilimu.ukubunjwa kunye nokwanda kokumelana nomhlwa.Uxinaniso oluphezulu lwe-dislocation ludla ngokuhambelana nokuchasana okuphantsi kwi-pitting, evumelana kakuhle nemilinganiselo ye-electrochemical.
Utshintsho kwimichiza yeekhemikhali ze-microdomains zezinto ezisisiseko zifundwe ngokucwangcisiweyo kusetyenziswa i-X-PEEM.Nangona ubuninzi bezinto ezixutywayo, i-Cr, i-Fe, i-Ni kunye ne-Ce39 zikhethwe apha, ekubeni i-Cr yinto ephambili yokwenziwa kwefilimu ye-passivation, i-Fe yeyona nto iphambili kwintsimbi, kunye ne-Ni yokwandisa i-passivation kunye nokulinganisa isakhiwo sesigaba se-ferrite-austenitic kunye nenjongo yokuguqulwa kwe-Ce.Ngokulungelelanisa amandla emitha ye-synchrotron, i-RAS yayigqunywe ukusuka phezulu kunye neempawu eziphambili ze-Cr (i-edge L2.3), i-Fe (i-edge L2.3), i-Ni (i-edge L2.3) kunye ne-Ce (i-edge M4.5).ukwakheka okushushu kunye nokuqengqeleka okubandayo kweCe-2507 SDSS.Uhlalutyo lwedatha olufanelekileyo lwenziwe ngokubandakanya ulungelelwaniso lwamandla kunye nedatha epapashiweyo (umzekelo, i-XAS 40, i-41 kwi-Fe L2, i-3 edges).
Kwikhiwane.Umzobo we-2 ubonisa imifanekiso ye-X-PEEM ye-hot-worked (Umfanekiso 2a) kunye ne-cold-rolled (Fig. 2d) Ce-2507 SDSS kunye nemiphetho ye-XAS ehambelanayo ye-Cr kunye ne-Fe L2,3 kwiindawo eziphawulwe ngabanye.I-L2,3 edge ye-XAS ihlola i-3d engabanjwanga ithi emva kwe-electron photoexcitation kumanqanaba okuhlukanisa i-spin-orbit 2p3 / 2 (L3 edge) kunye ne-2p1 / 2 (i-L2 edge).Ulwazi malunga nemeko ye-valence ye-Cr yafunyanwa kwi-XAS kwi-L2,3 edge kwi-Fig. 2b, e.Ukuthelekisa nabagwebi.I-42,43 ibonise ukuba iincopho ezine zabonwa kufuphi nomda we-L3, ogama lingu-A (578.3 eV), B (579.5 eV), C (580.4 eV) kunye ne-D (582.2 eV), ebonisa i-octahedral Cr3 +, ehambelana ne-Cr2O3 ion.I-spectra yovavanyo iyavumelana nezibalo zethiyori eziboniswe kwiipaneli ze-b kunye ne-e, ezifunyenwe kwizibalo ezininzi ze-crystal field kwi-interface ye-Cr L2.3 usebenzisa i-crystal field ye-2.0 eV44.Yomibini imiphezulu ye-SDSS esetyenzisiweyo eshushu kwaye iqengqeleke ngokubanda igqunywe ngomgangatho ofanayo we-Cr2O3.
umfanekiso we-X-PEEM we-thermal ye-SDSS ene-thermal deformed ehambelana ne-b Cr L2.3 edge kunye ne-c Fe L2.3 edge, d X-PEEM umfanekiso we-thermal we-SDSS epholileyo eqengqelekayo ehambelana ne-e Cr L2.3 edge kunye ne-f Fe L2 .3 edge side (f).Umboniso we-XAS ucwangciswe kwiindawo ezahlukeneyo zesithuba eziphawulwe kwimifanekiso eshushu (a, d), imigca echokoziweyo e-orenji ku-(b) kunye (e) imele umboniso ofanisiweyo we-XAS we-Cr3+ onexabiso le-crystal field ye-2.0 eV.Kwimifanekiso ye-X-PEEM, sebenzisa i-palette ye-thermal ukuphucula ukufundeka komfanekiso, apho imibala esuka eluhlaza okwesibhakabhaka ukuya ebomvu ilingana nokuqina kwe-X-ray yokufunxa (ukusuka ezantsi ukuya phezulu).
Kungakhathaliseki ukuba imo yekhemikhali yezi zinto zetsimbi, imeko yeekhemikhali zokongezwa kwe-Ni kunye ne-Ce i-alloying element kuzo zombini iisampuli zahlala zingatshintshi.Umzobo owongezelelweyo.Amanani 5-9 abonisa imifanekiso ye-X-PEEM kunye ne-XAS ehambelanayo ye-Ni kunye ne-Ce kwiindawo ezahlukeneyo kumphezulu we-hot-worked and cold-rolled samples.I-Ni XAS ibonisa iimeko ze-oxidation ye-Ni2+ phezu kwendawo yonke elinganisiweyo yemizekelo eshushu-esetyenziweyo kunye nebandayo (Ingxoxo eyoNgezelelweyo).Kufuneka kuqatshelwe ukuba, kwimeko yeesampulu ezisetyenzisiweyo ezishushu, isibonakaliso se-XAS se-Ce asizange sibonwe, ngelixa kwimeko yeesampuli ezipholileyo, i-spectrum ye-Ce3 + yabonwa.Ukuqwalaselwa kweendawo ze-Ce kwiisampuli eziqengqelekayo ezibandayo kubonise ukuba i-Ce ibonakala kakhulu kuhlobo lwemvula.
Kwi-SDSS ye-thermal deformed, akukho tshintsho lwesakhiwo sendawo kwi-XAS kwi-Fe L2, i-3 edge yabonwa (Umfanekiso 2c).Nangona kunjalo, i-Fe matrix micro-regionally itshintsha isimo sayo sekhemikhali kwiindawo ezisixhenxe ezikhethiweyo ezikhethiweyo ze-SDSS epholileyo, njengoko kuboniswe kwi-Fig. 2f.Ukongezelela, ukuze ufumane ingcamango echanekileyo yokutshintsha kwimeko ye-Fe kwiindawo ezikhethiweyo kwi-Fig. 2f, izifundo zendawo zendawo zenziwa (umzobo we-3 kunye ne-Supplementary Fig. 10) apho imimandla encinci yeesetyhula yakhethwa.I-XAS spectra ye-Fe L2, i-3 edge ye-α-Fe2O3 iinkqubo kunye ne-Fe2 + octahedral oxides zenziwe ngezibalo ezininzi ze-crystal field calculations usebenzisa i-crystal fields ye-1.0 (Fe2 +) kunye ne-1.0 (Fe3 +)44. Siyaqaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zinee-symmetries ezahlukeneyo zendawo45,46, i-Fe3O4 indibaniselwano zombini i-Fe2 + & Fe3 +, 47, kunye ne-FeO45 njenge-divalent ngokusemthethweni i-Fe2 + oxide (3d6). Siyaqaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zinee-symmetries ezahlukeneyo zendawo45,46, i-Fe3O4 inokudibanisa zombini i-Fe2 + & Fe3 +, 47, kunye ne-FeO45 njenge-divalent ngokusemthethweni i-Fe2 + oxide (3d6).Qaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zinee-symmetries ezahlukeneyo zendawo45,46, i-Fe3O4 idibanisa zombini i-Fe2 + kunye ne-Fe3 +, i-47 kunye ne-FeO45 ngendlela ye-divalent oxide Fe2 + (3d6).Qaphela ukuba i-α-Fe2O3 kunye ne-γ-Fe2O3 zinee-symmetries ezahlukeneyo zendawo45,46, i-Fe3O4 inendibaniselwano ye-Fe2 + kunye ne-Fe3 +, i-47 kunye ne-FeO45 isebenza njenge-divalent esemthethweni ye-Fe2 + oxide (3d6).Zonke i-Fe3+ ion kwi-α-Fe2O3 zinezithuba ze-Oh kuphela, ngelixa i-γ-Fe2O3 idla ngokumelwa yi-Fe3+ t2g [Fe3+5/3V1/3] umz. O4 spinel enezithuba umz.Ngoko ke, i-Fe3+ ion kwi-γ-Fe2O3 zineendawo zombini ze-Td kunye ne-Oh.Njengoko kukhankanyiwe kwiphepha elidlulileyo, i-45 nangona i-intensity ratio yezo zimbini zihluke, umlinganiselo wabo we-intensitet eg / t2g ngu-≈1, ngelixa kule meko umlinganiselo wokuqina oqatshelweyo umz / t2g malunga ne-1. Oku akubandakanyi ukuba kunokwenzeka ukuba kwimeko yangoku kuphela i-Fe3 + ikhona.Ukuqwalasela imeko ye-Fe3O4 kunye ne-Fe2 + kunye ne-Fe3 +, into yokuqala eyaziwayo ukuba inobuthakathaka (omelele) i-L3 edge ye-Fe ibonisa i-t2g encinci (enkulu) engahlaliyo.Oku kusebenza kwi-Fe2 + (Fe3 +), ebonisa ukuba uphawu lokuqala lokunyuka lubonisa ukwanda komxholo we-Fe2 + 47.Ezi ziphumo zibonisa ukuba ukuhlalisana kwe-Fe2 + kunye ne-γ-Fe2O3, i-α-Fe2O3 kunye / okanye i-Fe3O4 ilawula kwindawo epholileyo epholileyo yee-composites.
Ifotoelectron eyandisiweyo yemifanekiso ye-thermal imaging ye-XAS spectra (a, c) kunye (b, d) enqumla i-Fe L2,3 edge kwiindawo ezahlukeneyo zesithuba phakathi kweengingqi ezikhethiweyo ze-2 kunye no-E kwiiFig.2d.
Idatha yovavanyo efunyenweyo (umzobo we-4a kunye ne-Supplementary Fig. 11) icwangciswe kwaye ifaniswa nedatha ye-compounds ecocekileyo 40, 41, 48. Iintlobo ezintathu ezahlukeneyo zovavanyo oluphawulweyo lwe-Fe L-edge XAS spectra (XAS- 1, XAS-2 kunye ne-XAS-3: Umzobo 4a).Ngokukodwa, i-spectrum ye-2-a (echazwe njenge-XAS-1) kwi-Fig. 3b elandelwa yi-spectrum 2-b (ebhalwe i-XAS-2) yabonwa phezu kwendawo yonke yokukhangela, ngelixa i-spectra efana ne-E-3 yabonwa kumfanekiso we-3d (obhalwe ngokuthi XAS-3) wabonwa kwiindawo ezithile.Njengomthetho, iiparamitha ezine zisetyenziselwa ukuchonga iindawo ezikhoyo ze-valence kwisampulu ephantsi kophando: (1) iimpawu ze-spectral L3 kunye ne-L2, (2) izikhundla zamandla zeempawu ze-L3 kunye ne-L2, (3) umahluko wamandla L3-L2., ( 4) L2 / L3 ubukhulu bomlinganiselo.Ngokwezinto ezibonakalayo ezibonakalayo (umzobo 4a), zonke izinto ezintathu ze-Fe, ezizezi, i-Fe0, i-Fe2 +, kunye ne-Fe3 +, zikhona kumphezulu we-SDSS phantsi kophando.Umlinganiselo obaliweyo we-intensity ratio L2/L3 uphinde wabonisa ubukho bawo omathathu amacandelo.
Ukulinganisa kwe-XAS spectra ye-Fe kunye nedatha emithathu yovavanyo eyahlukeneyo (imigca eqinileyo i-XAS-1, i-XAS-2 kunye ne-XAS-3 ihambelana ne-2-a, i-2-b kunye ne-E-3 kwi-Fig. 2 kunye ne-3) Uthelekiso , i-Octahedrons Fe2+, i-Fe3+ kunye namaxabiso e-crystal field ye-1.0 eV, i-eV, i-experiment-5 kunye ne-ASX1. I-2, i-XAS-3) kunye nedatha ye-LCF ehambelanayo (umgca omnyama oqinileyo), kunye nakwifom ye-XAS-3 spectra kunye ne-Fe3O4 (imeko edibeneyo ye-Fe) kunye nemigangatho ye-Fe2O3 (i-Fe3 + ecocekileyo).
I-linear combination fit fit (LCF) yemigangatho emithathu ye-40, 41, 48 yayisetyenziselwa ukulinganisa ukubunjwa kwe-iron oxide.I-LCF yaphunyezwa kwii-spectra ezintathu ezikhethiweyo ze-Fe L-edge XAS ezibonisa owona mahluko aphezulu, angala, i-XAS-1, i-XAS-2 kunye ne-XAS-3, njengoko kubonisiwe kumfanekiso we-4b-d.Ukufakwa kwe-LCF, i-10% ye-Fe0 ithathelwe ingqalelo kuzo zonke iimeko ngenxa yokuba siqaphele i-ledge encinci kuyo yonke idatha, kwaye nangenxa yokuba isinyithi sesinyithi siyinxalenye ephambili yentsimbi. Enyanisweni, ubunzulu bokulingwa kwe-X-PEEM ye-Fe (~ 6 nm) 49 bukhulu kunoqikelelo oluqikelelweyo lwe-oxidation layer (kancinci> 4 nm), evumela ukufunyanwa kwesignali kwi-matrix yensimbi (Fe0) phantsi komgca we-passivation. Enyanisweni, ubunzulu bokulingwa kwe-X-PEEM ye-Fe (~ 6 nm) 49 bukhulu kunoqikelelo oluqikelelweyo lwe-oxidation layer (kancinci> 4 nm), evumela ukufunyanwa kwesignali kwi-matrix yensimbi (Fe0) phantsi komgca we-passivation. Действительно, пробная глубина X-PEEM для Fe (~ 6 нм)49 больше, чем предполагаемая толщина слоя окисления (немного > 4 iintsini), железной матрицы (Fe0) под пассивирующим слоем. Enyanisweni, i-probe ye-X-PEEM ubunzulu be-Fe (~ 6 nm) i-49 inkulu kunobunzima obucatshangelwayo be-oxidation layer (kancinci> i-4 nm), okwenza kube lula ukufumanisa isignali kwi-matrix yensimbi (Fe0) phantsi komgca we-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) (Fe0)的信号.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) 允方 允杀铁基体 (fe0) 的。Фактически, глубина обнаружения Fe (~ 6 нм) 49 с помощью X-PEEM больше, чем предполагаемая толщина оксидного слоя (немолного > 4 нал от железной матрицы (Fe0) ниже пассивирующего слоя. Enyanisweni, ubunzulu bokubona i-Fe (~ 6 nm) i-49 nge-X-PEEM bukhulu kunobunzima obulindelekileyo be-oxide layer (kancinci> 4 nm), evumela ukufunyanwa kwesignali kwi-matrix yensimbi (Fe0) ngaphantsi kwe-passivation layer. .Iindibaniso ezahlukeneyo ze-Fe2+ kunye ne-Fe3+ zenziwa ukufumana esona sisombululo sisesona sisesona sinokwenzeka kwidatha yovavanyo olujongweyo.Kwikhiwane.I-4b ibonisa i-spectrum ye-XAS-1 yokudibanisa i-Fe2 + kunye ne-Fe3 +, apho umlinganiselo we-Fe2 + kunye ne-Fe3 + wawufana malunga ne-45%, ebonisa ukuba i-oxidation states ye-Fe.Ngelixa kwi-spectrum ye-XAS-2, ipesenti ye-Fe2+ kunye ne-Fe3+ iba yi-~30% kunye ne-60%, ngokulandelanayo.I-Fe2+ ingaphantsi kwe-Fe3+.Umlinganiselo we-Fe2 + ukuya ku-Fe3, olingana no-1: 2, uthetha ukuba i-Fe3O4 inokubunjwa kumlinganiselo ofanayo phakathi kwe-Fe ion.Ukongezelela, kwi-spectrum ye-XAS-3, ipesenti ye-Fe2 + kunye ne-Fe3 + iba yi-~10% kunye ne-80%, ebonisa ukuguqulwa okuphezulu kwe-Fe2 + kwi-Fe3 +.Njengoko kukhankanyiwe ngasentla, i-Fe3 + inokuvela kwi-α-Fe2O3, γ-Fe2O3 okanye i-Fe3O4.Ukuqonda owona mthombo we-Fe3 +, i-spectrum ye-XAS-3 yenziwe ngemigangatho eyahlukeneyo ye-Fe3 + kwi-Figure 4e, ebonisa ukufana nemigangatho yomibini xa kuqwalaselwa i-B peak.Nangona kunjalo, ubuninzi bee-shoulder peaks (A: ukusuka kwi-Fe2 +) kunye ne-B / A intensity ratio ibonisa ukuba i-spectrum ye-XAS-3 isondele, kodwa ayihambelani ne-spectrum ye-γ-Fe2O3.Xa kuthelekiswa nobuninzi be-γ-Fe2O3, i-Fe 2p XAS incopho ye-A SDSS inobunzulu obuphezulu kancinane (Umfanekiso we-4e), obonisa ukuqina okuphezulu kwe-Fe2 +.Nangona i-spectrum ye-XAS-3 ifana ne-γ-Fe2O3, apho i-Fe3 + ikhona kwiindawo ze-Oh kunye ne-Td, ukuchongwa kweendawo ezahlukeneyo ze-valence kunye nokulungelelaniswa kuphela ecaleni kwe-L2,3 edge okanye i-L2 / L3 intensity ratio ihlala ingumxholo wophando oluqhubekayo.ingxoxo ngenxa yobunzima bezinto ezahlukeneyo ezichaphazela i-spectrum yokugqibela41.
Ukongeza kwiiyantlukwano ze-spectral kwimo yekhemikhali yemimandla ekhethiweyo enomdla echazwe ngasentla, i-heterogeneity yeekhemikhali zehlabathi yezinto eziphambili ze-Cr kunye ne-Fe nazo zavavanywa ngokuhlela yonke i-spectra ye-XAS efunyenwe kumphezulu wesampuli usebenzisa indlela ye-K-ithetha ukuhlanganisana.Iiprofayili ze-Cr L edge zenza amaqela amabini asasazwe ngokufanelekileyo kwiindawo ezishushu ezisetyenzisiweyo kunye neesampuli eziqengqelekayo eziboniswe kwiMifanekiso.5. Kucacile ukuba akukho zinguqu kwizakhiwo zengingqi zibonwa njengezifanayo, kuba iicentroids ezimbini ze-XAS Cr spectra ziyathelekiseka.Ezi milo zembonakalo yamaqela amabini ziphantse zafana nezo zihambelana ne-Cr2O342, okuthetha ukuba iileya ze-Cr2O3 zibekwe ngokulinganayo kwi-SDSS.
I-Cr L K-ithetha amaqela engingqi esekupheleni, kwaye b yi-XAS centroids ehambelanayo.Iziphumo ze-K-zithetha i-X-PEEM ukuthelekiswa kwe-SDSS epholileyo: c Cr L2.3 ummandla ophetheyo we-K-uthetha amaqoqo kunye ne-d ehambelana ne-XAS centroids.
Ukubonisa iimephu ezintsonkothileyo zomphetho we-FeL, amaqela amane kunye nantlanu aphuculweyo kunye ne-centroids ehambelanayo (iiprofayili ze-spectral) zisetyenziselwe imizekelo eshushu kunye ne-cold-rolled, ngokulandelanayo.Ngoko ke, ipesenti (%) ye-Fe2 + kunye ne-Fe3 + inokufumaneka ngokufaka i-LCF eboniswe kwi-Fig.4.I-pseudoelectrode enokubakho i-Epseudo njengomsebenzi we-Fe0 yayisetyenziselwa ukuveza i-microchemical inhomogeneity yefilimu ye-oxide yomhlaba.I-Epseudo iqikelelwa ngokungqongqo ngumgaqo wokuxuba,
apho \(\rm{E}_{\rm{Fe}/\rm{Fe}^{2 + (3 + )}}\) ilingana \(\rm{Fe} + 2e^ – \ ukuya \rm { Fe}^{2 + (3 + )}\), 0.440 kunye ne-0.036 V, ngokulandelelana.Imimandla enegunya eliphantsi inomxholo ophezulu we-Fe3 + compound.Ukuhanjiswa okunokubakho kwiisampuli ze-thermal deformed kunobumba obunqamlekileyo kunye noshintsho oluphezulu malunga ne-0.119 V (Umfanekiso 6a, b).Oku kusasazwa okunokwenzeka kuhambelana ngokusondeleyo kwi-topography yomhlaba (Umfanekiso 6a).Alukho olunye utshintsho oluxhomekeke kwisikhundla kwindawo yangaphakathi ye-laminar ephantsi yabonwa (Umfanekiso 6b).Ngokuchasene noko, uxhulumaniso lwee-oxide ezingafaniyo ezinemixholo eyahlukeneyo ye-Fe2 + kunye ne-Fe3 + kwi-SDSS epholileyo, umntu unokubona uhlobo olungafaniyo lwe-pseudopotential (Umfanekiso 6c, d).I-Fe3 + oxides kunye/okanye (i-oxy) hydroxides zezona ziqulatho zerusi kwintsimbi kwaye zingena kwioksijini nakumanzi50.Kule meko, iziqithi ezityebileyo kwi-Fe3 + zibhekwa njengezisasazwe kwindawo kwaye zinokuthi zithathwe njengeendawo ezinqabileyo.Ngexesha elifanayo, i-gradient kwintsimi enokwenzeka, kunokuba ixabiso elipheleleyo lezinto ezinokubakho, linokusetyenziswa njengesalathisi sokwakhiwa kweendawo ezisebenzayo ze-corrosion.Olu lwabiwo olungalinganiyo lwe-Fe2 + kunye ne-Fe3 + phezu kwe-SDSS epholileyo epholileyo inokutshintsha i-chemistry yendawo kwaye inikeze indawo esebenzayo esebenzayo ngexesha lokuphuka kwefilimu ye-oxide kunye nokuphendula kwe-corrosion, evumela ukuba i-matrix yensimbi ephantsi iqhubeke nokugqwala, okubangela ukungafani kwangaphakathi.iipropathi kunye nokunciphisa iimpawu zokukhusela ze-passivating layer.
I-K-ithetha amaqoqo kunye ne-XAS centroids ehambelanayo kwingingqi ye-Fe L2.3 edge ye-X-PEEM ac eshushu-eshushu kunye ne-df ye-SDSS epholileyo.a, d K-ithetha iiploti zeqela ezigqunywe kwi X-PEEM imifanekiso.Ukubalwa okunokwenzeka kwepseudoelectrode (Epseudo) kukhankanyiwe kunye neploti yeqela le-K.Ukukhanya komfanekiso we-X-PEEM, njengombala kwi-Fig.
Ngokulinganayo iyunifomu ye-Cr kodwa imo yeekhemikhali ezahlukeneyo ze-Fe ikhokelela kumonakalo wefilimu ye-oxide eyahlukeneyo kunye neepateni zokubola kwi-Ce-2507 eshushu-esetyenziweyo kunye nebandayo.Le propati ebandayo iqengqeleke i-Ce-2507 ifundwe kakuhle.Ngokubhekiselele ekubunjweni kweeoksidi kunye neehydroxides zeFe kumoya ojikelezayo kulo msebenzi uphantse ungathathi hlangothi, iimpendulo zimi ngolu hlobo lulandelayo:
Ezi mpendulo zingentla zenzeka kwezi meko zilandelayo ngokusekelwe kuhlalutyo lwe-X-PEEM.Igxalaba elincinci elihambelana ne-Fe0 lidibene nentsimbi ephantsi yensimbi.Ukusabela kwe-metallic Fe kunye nokusingqongileyo kubangela ukwakheka kwe-Fe(OH)2 umaleko (equation (5)), ephucula umqondiso we-Fe2+ kwi-Fe L-edge XAS.Ukutshatyalaliswa kwexesha elide emoyeni kunokubangela ukubunjwa kwe-Fe3O4 kunye / okanye i-Fe2O3 oxides emva kwe-Fe (OH) 252,53.Iifom ezimbini ezizinzileyo ze-Fe, i-Fe3O4 kunye ne-Fe2O3, zinokuphinda zifake kwi-Cr3 + ecebileyo yokukhusela, apho i-Fe3O4 ikhetha i-uniform kunye nesakhiwo esinamathele.Ubukho beziphumo zombini kwimixube ye-oxidation states (XAS-1 spectrum).I-spectrum ye-XAS-2 ihambelana kakhulu ne-Fe3O4.Ngelixa ukuqwalaselwa kwe-XAS-3 spectra kwiindawo ezininzi kubonise uguqulo olupheleleyo kwi-γ-Fe2O3.Ekubeni ubunzulu bokungena kwe-X-rays evuliweyo malunga ne-50 nm, umqondiso ovela kumaleko asezantsi uphumela ekuphakameni okuphezulu kwe-A peak.
I-spectrum ye-XPA ibonisa ukuba i-Fe component kwifilimu ye-oxide inesakhiwo esine-layer edibeneyo kunye ne-Cr oxide layer.Ngokuchaseneyo neempawu zokudlula ngenxa ye-inhomogeneity yendawo ye-Cr2O3 ngexesha lokubola, nangona i-uniform layer ye-Cr2O3 kulo msebenzi, ukuxhathisa okuphantsi kwe-corrosion kubonwa kule meko, ngakumbi kwiisampuli ezipholileyo.Ukuziphatha okubonwayo kunokuqondwa njenge-heterogeneity yemeko ye-oxidation yeekhemikhali kwinqanaba eliphezulu (Fe), elichaphazela ukusebenza kwe-corrosion.Ngenxa ye-stoichiometry efanayo yomgangatho ophezulu (i-iron oxide) kunye nomgangatho ophantsi (i-chromium oxide) i-52,53 ukusebenzisana okungcono (ukunamathela) phakathi kwabo kukhokelela ekuthuthweni okucothayo kwe-iron okanye i-oxygen ion kwi-lattice, leyo, ikhokelela ekunyuseni kokumelana nokubola.Ngoko ke, umlinganiselo oqhubekayo we-stoichiometric, okt imo enye ye-oxidation ye-Fe, ikhethwa ngokutshintsha ngokukhawuleza kwe-stoichiometric.I-SDSS ene-heat-deformed inomgangatho ofanayo ngakumbi, umaleko okhuselweyo oxineneyo, kunye nokumelana nokugqwesa okungcono.Nangona i-SDSS epholileyo ebandayo, ubukho beziqithi ze-Fe3 + ezizityebi phantsi komgangatho wokukhusela ziphula ingqibelelo yomhlaba kwaye zibangela ukubola kwe-galvanic kunye ne-substrate esondeleyo, ekhokelela ekuhlahleni okubukhali kwi-Rp (Itheyibhile 1).I-spectrum ye-EIS kunye nokuxhathisa kwayo kuyancipha.Ingabonwa ukuba ukuhanjiswa kwendawo ye-Fe3 + iziqithi ezityebileyo ngenxa ye-deformation yeplastiki ichaphazela kakhulu ukuxhatshazwa kwe-corrosion, okuyimpumelelo kulo msebenzi.Ke, olu phononongo lubonisa imifanekiso ye-spectroscopic microscopic yokunciphisa ukuxhathisa ukubola kweesampulu ze-SDSS ezifundwe yindlela yokuguqulwa kweplastiki.
Ukongeza, nangona umxube womhlaba onqabileyo kwi-steel yesigaba esiphindwe kabini ubonisa ukusebenza okungcono, ukunxibelelana kwesi sixhobo sokongeza kunye ne-matrix yentsimbi yomntu ngamnye ngokwendlela yokuziphatha komhlwa ngokwe-spectroscopic microscopy kuhlala kunzima.Inkangeleko yemiqondiso ye-Ce (nge-XAS M-edges) ibonakala kuphela kwiindawo ezimbalwa ngexesha lokuqengqeleka okubandayo, kodwa iyanyamalala ngexesha lotshintsho olushushu lwe-SDSS, ebonisa imvula yendawo ye-Ce kwimatrix yentsimbi, kune-homogeneous alloying.Ngelixa ingaphuculi kakhulu iipropathi zemishini ye-SDSS6,7, ubukho bezinto ezinqabileyo zomhlaba kunciphisa ubungakanani bezinto ezifakiweyo kwaye kucingelwa ukuba zithintele ukugoba kwindawo yokuqala54.
Ekugqibeleni, lo msebenzi ubonisa umphumo we-heterogeneity yomhlaba kwi-corrosion ye-2507 SDSS eguqulelwe nge-cerium ngokulinganisa umxholo wekhemikhali we-nanoscale components.Siphendula umbuzo wokuba kutheni insimbi engenasici igqwala naphantsi komgangatho okhuselweyo we-oxide ngokulinganisa i-microstructure yayo, i-surface chemistry, kunye nokusetyenzwa komqondiso usebenzisa i-K-means clustering.Kuye kwasekwa ukuba iziqithi ezityebileyo kwi-Fe3 +, kubandakanywa nokulungelelaniswa kwe-octahedral kunye ne-tetrahedral kunye nayo yonke into edibeneyo ye-Fe2 +/Fe3 +, ngumthombo womonakalo kunye nokubola kwefilimu epholileyo ye-oxide ye-SDSS.I-Nanoislands elawulwa yi-Fe3 + ikhokelela ekuxhathiseni ukonakala kwe-corrosion naxa kukho i-stoichiometric eyaneleyo ye-Cr2O3 passivating layer.Ukongeza kwinkqubela phambili ye-methodological ekunqumeni umphumo we-nanoscale chemical heterogeneity kwi-corrosion, umsebenzi oqhubekayo ulindeleke ukuba ukhuthaze iinkqubo zobunjineli zokuphucula ukuxhathisa kwe-corrosion of steels stainless steelmaking.
Ukulungiselela i-Ce-2507 SDSS ingot esetyenziswa kolu phando, ukwakheka okuxutyiweyo kuquka Fe-Ce master ingxubevange itywinwe ngombhobho yentsimbi esulungekileyo yanyibilika kwi 150 kg medium frequency induction eziko ukuvelisa intsimbi etyhidiweyo kwaye bagalelwa ngundo.Ukwakheka kweekhemikhali ezilinganisiweyo (wt%) zidweliswe kwiTheyibhuli eyoNgezelelweyo yesi-2.Emva koko i-annealed kwi-1050 ° C kwimizuzu engama-60 ukufumana insimbi kwimeko yesisombululo esiqinileyo, kwaye yacinywa emanzini kwiqondo lokushisa.Iisampulu ezifundiweyo zaphononongwa ngokweenkcukacha kusetyenziswa iTEM kunye ne-DOE ukufunda izigaba, ubungakanani beenkozo kunye nemorphology.Ulwazi oluthe vetshe malunga neesampuli kunye nenkqubo yokuvelisa inokufumaneka kweminye imithombo6,7.
Iisampulu ze-Cylindrical (φ10 mm × 15 mm) zoxinzelelo olushushu zicutshungulwa ukuze i-axis ye-cylinder ihambelane nolwalathiso lwe-deformation yebhloko.Uxinzelelo oluphezulu lweqondo lokushisa lwenziwa kumaqondo okushisa ahlukeneyo kwi-1000-1150 ° C usebenzisa i-Gleeble-3800 simulator ye-thermal kwi-standing strain rate kwi-0.01-10 s-1.Ngaphambi kokuguqulwa, iisampulu zatshiswa kwizinga le-10 ° C s-1 kwi-2 min kwiqondo lokushisa elikhethiweyo ukuphelisa i-gradient yeqondo lokushisa.Emva kokufezekisa ukufana kweqondo lokushisa, isampuli yakhubazeka kwixabiso lokwenene loxinzelelo lwe-0.7.Emva kokuguqulwa, iisampulu zacinywa ngokukhawuleza ngamanzi ukuze kugcinwe isakhiwo esonakele.Lo mzekelo uqiniweyo ke uyasikwa ngokungqamene nelathiso loxinzelelo.Kwesi sifundo sithile, sikhethe umfuziselo onemeko yoxinzelelo olushushu lwe-1050 ° C, 10 s-1 kuba ubulukhuni obuncinci obuqatshelweyo babuphezulu kuneminye imizekelo7.
Iisampulu ezinkulu (80 × 10 × 17 mm3) ze-Ce-2507 isisombululo esiqinileyo zisetyenziswe kwi-LG-300 yesigaba sesithathu se-asynchronous two-roll mill eneempawu ezingcono kakhulu zomatshini phakathi kwawo onke amanye amanqanaba okuguqula6.Izinga loxinzelelo kunye nokunciphisa ubukhulu bendlela nganye yi-0.2 m·s-1 kunye ne-5%, ngokulandelanayo.
Indawo yokusebenzela ye-electrochemical ye-Autolab PGSTAT128N isetyenziselwe imilinganiselo ye-electrochemical ye-SDSS emva kokuqengqeleka okubandayo ukuya kuma-90% okucutha ubukhulu (1.0 elingana noxinzelelo lokwenyani) kwaye emva koxinzelelo olushushu kwi-1050 ° C kwi-10 s-1 ukuya kuxinzelelo lwenyani lwe-0.7.Indawo yokusebenzela ineseli ye-electrode emithathu ene-calomel electrode egcweleyo njenge-electrode yereferensi, i-graphite counter electrode, kunye nesampuli ye-SDSS njenge-electrode esebenzayo.Iisampuli zinqunywe kwiisilinda ezinobubanzi be-11.3 mm, ukuya emacaleni apho iingcingo zobhedu zathengiswa.Iisampuli zaye zalungiswa nge-epoxy, zishiya indawo evulekileyo yokusebenza ye-1 cm2 njenge-electrode esebenzayo (icala elisezantsi lesampulu ye-cylindrical).Lumka ngexesha lokunyanga i-epoxy kunye nesanti elandelayo kunye nokupolisha ukunqanda ukuqhekeka.Iindawo ezisebenzayo ziphantsi kwaye ziphuculwe nge-diamond polishing suspension kunye ne-particle size ye-1 μm, ihlanjwe ngamanzi adibeneyo kunye ne-ethanol, kwaye yomiswe emoyeni obandayo.Ngaphambi kwemilinganiselo ye-electrochemical, iisampulu ezikhazimlisiweyo zavezwa emoyeni kangangeentsuku ezininzi ukwenza ifilimu yendalo ye-oxide.Isisombululo se-aqueous se-FeCl3 (6.0 wt%), esizinzile kwi-pH = 1.0 ± 0.01 kunye ne-HCl ngokweengcebiso ze-ASTM, isetyenziselwa ukukhawulezisa ukubola kwensimbi engenasici55 kuba i-corrosion phambi kwee-ion ze-chloride ezinamandla oxidizing umthamo kunye ne-pH ephantsi ye-G3 kunye nemigangatho ye-A9.Rhixiza isampuli kwisisombululo sovavanyo lweyure e-1 ukufikelela kufutshane nemeko ezinzileyo ngaphambi kokwenza nayiphi na imilinganiselo.Isisombululo esiqinileyo, i-hot-formed, kunye ne-cold-rolled, imilinganiselo ye-impedance yenziwa kwiindawo ezivulekileyo zesekethe (OPC) ye-0.39, 0.33, kunye ne-0.25 V, ngokulandelanayo, kwi-frequency range ukusuka kwi-1 105 ukuya kwi-0.1 Hz kunye ne-amplitude ye-5 mV.Zonke iimvavanyo zeekhemikhali ziphindwe ubuncinane ngamaxesha e-3 phantsi kweemeko ezifanayo ukuze kuqinisekiswe ukuveliswa kwedatha.
Kwimilinganiselo ye-HE-SXRD, iibhloko zensimbi ze-rectangular duplex ezilinganisa i-1 × 1 × 1.5 mm3 zilinganiswe ukulinganisa ukubunjwa kwesigaba se-beam se-Brockhouse high-energy wiggler kwi-CLS, eCanada56.Ukuqokelelwa kwedatha kuqhutywe kwi-geometry ye-Debye-Scherrer okanye i-geometry yokudlulisa kwiqondo lokushisa.I-X-reyi ye-wavelength elungelelaniswe ne-LaB6 calibrator yi-0.212561 Å, ehambelana ne-58 keV, ephezulu kakhulu kune-Cu Kα (8 keV) esetyenziswa ngokuqhelekileyo njengomthombo we-X-reyi elebhu.Isampuli ibekwe kumgama we-740 mm ukusuka kumtshini.Umthamo wokufumanisa isampuli nganye ngu-0.2 × 0.3 × 1.5 mm3, ochongwa ngubukhulu be-beam kunye nobukhulu besampulu.Zonke iinkcukacha zaqokelelwa kusetyenziswa i-Perkin Elmer detector yendawo, i-flat panel X-ray detector, 200 µm pixels, 40×40 cm2 kusetyenziswa ixesha lokuvezwa le-0.3 s kunye neefreyimu eziyi-120.
Imilinganiselo ye-X-PEEM yeendlela ezimbini ezikhethiweyo zemodeli zenziwa kwi-Beamline MAXPEEM PEEM kwisikhululo sokugqibela kwi-laboratory ye-MAX IV (eLund, eSweden).Iisampulu zalungiswa ngendlela efanayo nemilinganiselo ye-electrochemical.Iisampulu ezilungisiweyo zigcinwe emoyeni iintsuku ezininzi kwaye zihlanjululwe kwigumbi le-vacuum ye-ultrahigh ngaphambi kokuba zihlanjululwe ngeefotoni ze-synchrotron.Isisombululo samandla somgca we-beam sifunyenwe ngokulinganisa i-ion isivuno se-spectrum kummandla wokuvuselela ukusuka kwi-N 1 s ukuya kwi-1 \ (\pi _g^ \st\) kufuphi ne-hv = 401 eV kwi-N2 ngokuxhomekeka kwamandla efoton kwi-E3/2, 57. Uqikelelo lwe-spectra elilinganisiweyo lomgca we-spectra ye-0. Ngoko ke, isisombululo samandla e-beamline sasiqikelelwa ukuba yi-E / ∆E = 700 eV / 0.3 eV> 2000 kunye ne-flux ≈1012 ph / s ngokusebenzisa i-monochromator ye-SX-700 elungisiweyo kunye ne-Si 1200-line mm-1 grating ye-Fe 2p, i-L3pdge, i-L3pdge, i-L3pdge2, i-Cr32 edge2, i-Cr32, i-SX-700 eguquliweyo kunye Ce M4,5 edge. Ngoko ke, isisombululo samandla e-beamline sasiqikelelwa ukuba yi-E / ∆E = 700 eV / 0.3 eV> 2000 kunye ne-flux ≈1012 ph / s ngokusebenzisa i-monochromator ye-SX-700 elungisiweyo kunye ne-Si 1200-line mm-1 grating ye-Fe 2p, L2.2. kunye Ce M4.5 edge. Таким образом, энергетическое разрешение канала пучка было оценено как E/∆E = 700 эВ/0,3 эВ > 2000 и поток ≈1012 umfanekiso weskrini нохроматора SX-700 с решеткой Si 1200 штрихов/мм для Fe кромка 2p L2,3, кромка Cr 2p L2,3, кромка Ni 2p L2,3 и кромка Ce M4,5. Ngaloo ndlela, isisombululo samandla somzila we-beam siqikelelwe njenge-E / ∆E = 700 eV / 0.3 eV> 2000 kunye ne-flux ≈1012 f / s usebenzisa i-monochromator eguquliweyo ye-SX-700 kunye ne-Si grating ye-1200 imigca / mm ye-Fe edge 2p L2, 3, i-Cep edge 2, i-Cep edge 2, i-Cep edge 2, i-Cep edge 2, i-M2 edge, i-3, i-Cep edge, i-2, i-M2 edge. 4.5.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,通过使用带有1Si 120 -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 為為 為 δe = 700 EV/0.3 EV> 2000 kunye ≈1012 PH/S , 使用带有 带有 12 mm . SX-700 单色器 于 于 用 用 用Fe 2p L2.3 边缘、Cr 2p L2.3 边缘、Ni 2p L2.3 边缘和Ce M4.5 边缘.Ngaloo ndlela, xa usebenzisa i-monochromator ye-SX-700 elungisiweyo kunye nomgca we-1200 we-Si grating.3, Cr edge 2p L2.3, Ni edge 2p L2.3 kunye Ce edge M4.5.Skena amandla efoton kumanyathelo e-0.2 eV.Ngamandla onke, imifanekiso ye-PEEM irekhodwe ngokusebenzisa i-TVIPS F-216 i-fiber-coupled CMOS detector ene-2 ​​x 2 bins, ebonelela ngesisombululo se-1024 × 1024 pixels kwi-20 µm kwintsimi yokujonga.Ixesha lokuvezwa kwemifanekiso yayiyi-0.2 s, i-avareji ye-16 izakhelo.Amandla omfanekiso we-photoelectron akhethwe ngendlela yokubonelela ngowona mqondiso uphezulu we-electron yesibini.Yonke imilinganiselo yenziwa kwiziganeko eziqhelekileyo kusetyenziswa i-linearly polarized photon beam.Ulwazi oluninzi malunga nemilinganiselo inokufumaneka kwisifundo sangaphambili.Emva kokufunda imodi yokufumanisa i-electron yield (TEY) kunye nokusetyenziswa kwayo kwi-X-PEEM49, ubunzulu bovavanyo lwale ndlela buqikelelwa malunga ne-4-5 nm ye-Cr signal kunye ne-6 nm ye-Fe.Ubunzulu be-Cr busondele kakhulu kubukhulu befilimu ye-oxide (~ 4 nm) 60,61 ngelixa ubunzulu be-Fe bukhulu kunobunzima.I-XRD eqokelelwe kumda we-Fe L ngumxube we-XRD ye-iron oxides kunye ne-Fe0 ukusuka kwi-matrix.Kwimeko yokuqala, ukuqina kwee-electron ezikhutshwayo zivela kuzo zonke iintlobo zee-electron ezinokuthi zibe negalelo kwi-TEY.Nangona kunjalo, isignali yentsimbi ecocekileyo idinga amandla aphezulu e-kinetic ukwenzela ukuba ii-electron zidlule kwi-oxide layer ukuya phezulu kwaye ziqokelelwe yi-analyzer.Kule meko, uphawu lwe-Fe0 lubangelwa ikakhulu kwi-electrons ye-LVV Auger, kunye nee-electron zesibini ezikhutshwa ngabo.Ukongeza, ubunzulu be-TEY obunegalelo kwezi electron zibola ngexesha lendlela yokuphunyuka kwe-electron, inciphisa ngakumbi impendulo ye-Fe0 kwimephu ye-iron XAS.
Ukudibanisa i-data mining kwi-cube yedatha (idatha ye-X-PEEM) yinyathelo eliphambili ekukhupheni ulwazi olufanelekileyo (iikhemikhali okanye iipropati ezibonakalayo) kwindlela yobuninzi.I-K-ithetha ukuhlanganisana isetyenziswa ngokubanzi kwiinkalo ezininzi, kubandakanywa umbono womatshini, ukusetyenzwa kwemifanekiso, ukuqondwa kwepateni engagadwanga, ubukrelekrele bokwenziwa, kunye nohlalutyo lokuhlelwa.Ngokomzekelo, i-K-indlela yokudibanisa iqhube kakuhle ekuhlanganiseni idatha ye-hyperspectral yomfanekiso.Ngokomgaqo, kwidatha yezinto ezininzi, i-algorithm ye-K-ithetha ngokulula iyakwazi ukuhlanganisana ngokusekelwe kulwazi malunga neempawu zabo (iipropati zamandla e-photon).I-K-ithetha ukuhlanganisa yi-algorithm ephindaphindayo yokwahlula idatha kumaqela e-K angahambelaniyo (amaqela), apho ipixel nganye iyeyeqela elithile ngokuxhomekeke kulwabiwo lwesithuba lwemichiza ye-inhomogeneity kwi-steel microstructural composition.I-algorithm ye-K ibandakanya izigaba ezibini: kwinqanaba lokuqala, i-K centroids ibalwa, kwaye kwinqanaba lesibini, inqaku ngalinye linikwe i-cluster ene-centroids engabamelwane.Umbindi womxhuzulane weqela uchazwa njenge-arithmetic mean yamanqaku edatha (i-XAS spectrum) yelo qela.Kukho imigama eyahlukeneyo yokuchaza iicentroids ezingabamelwane njengomgama we-Euclidean.Kumfanekiso wegalelo we px,y (apho x kunye no y zisisombululo kwiipixels), CK ngumbindi womxhuzulane weqela;lo mfanekiso ungahlulwa (udityaniswe) ube ngamaqela e-K usebenzisa i-K-means63.Amanyathelo okugqibela e-K-indlela yokuhlanganisa algorithm ngala:
Inyathelo 2. Bala ubulungu bazo zonke pixels ngokwe centroid yangoku.Umzekelo, ibalwa ukusuka kumgama we-Euclidean d phakathi kombindi kunye nepikseli nganye:
Inyathelo lesi-3 Yabela ipikseli nganye kweyona centroid ikufutshane.Emva koko bala kwakhona izithuba ze-K centroid ngolu hlobo lulandelayo:
Inyathelo 4. Phinda inkqubo (i-equations (7) kunye (8)) de i-centroids ihlangane.Iziphumo zomgangatho wokuhlanganisana wokugqibela zinxulunyaniswa kakhulu nolona khetho lubalaseleyo lweesentimitha zokuqala.Ulwakhiwo lwedatha ye-PEEM yemifanekiso yentsimbi, ngokuqhelekileyo i-X (x × y × λ) yicube yedatha ye-3D, ngelixa i-x kunye ne-y axes imele ulwazi lwesithuba (isisombululo se-pixel) kunye ne-λ axis ihambelana nefoton.umfanekiso we-spectral wamandla.I-algorithm ye-K isetyenziselwa ukuphonononga imimandla enomdla kwidatha ye-X-PEEM ngokwahlula iipikseli (i-clusters okanye iibhloko ezisezantsi) ngokweempawu zazo ze-spectral kunye nokukhupha ii-centroids ezilungileyo (i-XAS spectral profiles) kuhlalutyi ngamnye.iqela).Isetyenziselwa ukufunda ukuhanjiswa kwendawo, utshintsho lwembonakalo yendawo, ukuziphatha kwe-oxidation, kunye namazwe amachiza.Ngokomzekelo, i-algorithm yokudibanisa i-K isetyenziselwa i-Fe L-edge kunye ne-Cr L-edge imimandla kwiindawo ezishushu ezisebenzayo kunye ne-X-PEEM ebandayo.Amanani ahlukeneyo eqela le-K (iingingqi ze-microstructure) zavavanywa ukufumana awona maqela afanelekileyo kunye neecentroids.Xa la manani ebonisiwe, ii-pixels zikwabelwa kwi-cluster centroids ehambelanayo.Ukwabiwa kombala ngamnye kuhambelana nombindi weqela, ebonisa ukucwangciswa kwendawo yezinto zekhemikhali okanye ezibonakalayo.I-centroids ekhutshiweyo yindibaniselwano yomgca ye-spectra ecocekileyo.
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Ixesha lokuposa: Oct-24-2022