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Hōʻike i kahi carousel o ʻekolu mau paheʻe i ka manawa hoʻokahi. E hoʻohana i nā pihi Previous a me Next e neʻe i ʻekolu mau paheʻe i ka manawa hoʻokahi, a i ʻole e hoʻohana i nā pihi slider ma ka hopena e neʻe i ʻekolu mau paheʻe i ka manawa hoʻokahi.
ʻO ke kila kila i hoʻohana nui ʻia a me kāna mau mana i hana ʻia he kūpaʻa i ka pala i nā kūlana ambient ma muli o ka papa passivation i hana ʻia me ka chromium oxide. ʻO ka pala a me ka erosion o ke kila e pili pinepine ʻia me ka luku ʻia ʻana o kēia mau papa, akā kākaʻikahi me ke ʻano o nā inhomogeneities o ka ʻili, ma muli o ka pae microscopic. Ma kēia hana, ʻo ka heterogeneity o ka ʻili kemika nanoscale, i ʻike ʻia e ka microscopy spectroscopic a me ka nānā ʻana o chemometric, e hoʻomalu koke ana i ka haki a me ka pala o ke kila kila super duplex cerium i hoʻololi ʻia i ke anu 2507 (SDSS) i ka wā o kona deformation wela. ʻOiai ua hōʻike ka microscopy photoelectron X-ray i kahi uhi like o ka papa Cr2O3 kūlohelohe, ʻaʻole maikaʻi ka hana passivation o ka SDSS i ʻōwili anu ma muli o ka hoʻolaha kūloko o nā nanoislands waiwai Fe3+ ma ka papa oxide Fe/Cr. Hāʻawi kēia ʻike unahi atomika i kahi ʻike hohonu o ka pala kila kila a manaʻo ʻia e kōkua i ka hakakā ʻana i ka pala o nā metala alloy kiʻekiʻe like.
Mai ka wā i hana ʻia ai ke kila kila kila, ua hoʻopili ʻia nā waiwai anti-corrosion o ka ferrochrome i ka chromium, kahi e hana ai i nā oxides/oxyhydroxides ikaika a hōʻike i kahi ʻano passivating ma ka hapa nui o nā wahi. Ke hoʻohālikelike ʻia me nā kila kila maʻamau (austenitic a me ferritic) 1, 2, 3, ʻoi aku ka maikaʻi o ke kūpaʻa ʻana o nā kila kila super duplex (SDSS) i ka corrosion a me nā waiwai mechanical maikaʻi loa. ʻO ka hoʻonui ʻana i ka ikaika mechanical e ʻae ai i nā hoʻolālā māmā a ʻoi aku ka liʻiliʻi. I ka hoʻohālikelike ʻana, he kiʻekiʻe ke kūpaʻa o ka SDSS waiwai i ka pitting a me ka crevice corrosion, e hopena ana i kahi ola lawelawe lōʻihi, no laila e hoʻonui ana i kāna noi i ka kaohi haumia, nā pahu kemika, a me ka ʻoihana aila a me ke kinoea ma waho o ke kai4. Eia nō naʻe, ʻo ka laulā haiki o nā mahana mālama wela a me ka formability maikaʻi ʻole e pale aku i kā lākou noi ākea. No laila, ua hoʻololi ʻia ka SDSS e hoʻomaikaʻi i ka hana ma luna. No ka laʻana, ua hoʻolauna ʻia ka hoʻololi ʻana o Ce ma SDSS 2507 (Ce-2507) me ka nui o ka nitrogen6,7,8. ʻO ka mea honua laha ʻole (Ce) ma kahi kūpono o 0.08 wt.% he hopena maikaʻi ia i nā waiwai mechanical o ka DSS, ʻoiai e hoʻomaikaʻi ana i ka hoʻomaʻemaʻe ʻana o ka palaoa a me ka ikaika o ka palena palaoa. Hoʻomaikaʻi ʻia hoʻi ke kūpaʻa i ka ʻaʻahu a me ka palaho, ka ikaika tensile a me ka ikaika hua, a me ka hana wela. Hiki i ka nui o ka naikokene ke pani i ka nui o ka nickel pipiʻi, e hoʻolilo ana i ka SDSS i mea kūpono i ke kumukūʻai10.
I kēia manawa, ua hoʻololi ʻia ka SDSS i ka plastically ma nā mahana like ʻole (cryogenic, anu a me ka wela) e hoʻokō i nā waiwai mechanical maikaʻi loa6,7,8. Eia nō naʻe, ʻo ke kūpaʻa maikaʻi loa o ka SDSS ma muli o ke alo o kahi kiʻiʻoniʻoni oxide lahilahi ma luna o ka ʻili e hoʻopilikia ʻia e nā mea he nui e like me ka heterogeneity kūlohelohe ma muli o ke alo o nā ʻāpana heterogeneous me nā palena palaoa like ʻole, nā precipitates makemake ʻole ʻia a me nā pane like ʻole.7. No laila, ʻo ke aʻo ʻana i nā waiwai microscopic domain o ia mau kiʻiʻoniʻoni a hiki i ka pae o ke ʻano uila e lilo i mea koʻikoʻi no ka hoʻomaopopo ʻana i ka SDSS corrosion a koi i nā ʻano hana hoʻokolohua paʻakikī. A hiki i kēia manawa, ʻo nā ʻano hana ʻili e like me Auger electron spectroscopy11 a me X-ray photoelectron spectroscopy12,13,14,15 a me ka paʻakikī X-ray photoemission microscopy (HAX-PEEM)16 ua hiki ʻole ke ʻike i nā ʻokoʻa kemika i nā papa o ka ʻili. nā kūlana kemika o ka mea like ma nā wahi like ʻole o ka hakahaka nanoscale. Ua hoʻopili kekahi mau noiʻi hou i ka oxidation kūloko o ka chromium me ke ʻano corrosion i ʻike ʻia o nā kila kila austenitic17, nā kila martensitic18 a me SDSS19,20. Eia nō naʻe, ua kālele nui kēia mau noiʻi i ka hopena o ka heterogeneity Cr (e laʻa, Cr3+ oxidation state) ma ke kūpaʻa ʻana i ka corrosion. Hiki ke hana ʻia ka heterogeneity lateral i nā mokuʻāina oxidation o nā mea e nā hui like ʻole me nā mea like, e like me nā oxides hao. ʻO kēia mau hui, i hoʻoilina i kahi liʻiliʻi ma muli o ka mālama ʻana i ka thermomechanical, aia kokoke kekahi i kekahi, akā ʻokoʻa i ka haku mele a me ke kūlana oxidation16,21. No laila, i mea e ʻike ai i ka haki ʻana o nā kiʻiʻoniʻoni oxide a me ka pitting ma hope, pono e hoʻomaopopo i ka heterogeneity o ka ʻili ma ka pae microscopic. ʻOiai kēia mau koi, ʻaʻole i lawa nā kuhi quantitative e like me ka heterogeneity lateral i ka oxidation, ʻoi aku hoʻi no Fe ma ka nano- a me ka atomic scale, a ʻaʻole i ʻimi ʻia kona pilina me ke kūpaʻa corrosion. A hiki i kēia manawa koke nei, ua wehewehe ʻia ke ʻano kemika o nā mea like ʻole, e like me Fe a me Ca22, ma nā laʻana kila me ka hoʻohana ʻana i ka microscopy photoelectron X-ray palupalu (X-PEEM) i loko o nā hale hana radiation synchrotron nanoscale. I hui pū ʻia me ka spectroscopy absorption X-ray sensitive chemically (XAS), hiki iā X-PEEM ke ana i nā ana XAS me ka hoʻonā spatial a me spectral kiʻekiʻe, e hāʻawi ana i ka ʻike kemika e pili ana i ka haku mele ʻana o nā mea a me ko lākou kūlana kemika me ka hoʻonā spatial a hiki i ka iwakāluakūmākolu nanometer scale. . Hoʻomaʻalahi kēia nānā spectromicroscopic o ka hoʻomaka ʻana i nā nānā kemika kūloko a hiki ke hōʻike i nā loli kemika i loko o ka hakahaka o ka papa hao i noiʻi ʻole ʻia ma mua.
Hoʻonui kēia haʻawina i nā pono o PEEM i ka ʻike ʻana i nā ʻokoʻa kemika ma ka nanoscale a hōʻike i kahi ʻano loiloi ʻili atomika intuitive no ka hoʻomaopopo ʻana i ke ʻano corrosion o Ce-2507. Hoʻohana ia i kahi ʻano chemometric K-means24 clustered e palapala i ka homogeneity kemika honua (hetero) o nā mea i komo, nona nā kūlana kemika i hōʻike ʻia ma kahi hōʻike helu. I ka hoʻohālikelike ʻana i ka corrosion i hoʻomaka ʻia e ka luku ʻia ʻana o ka ʻili chromium oxide i ka hihia kuʻuna, ʻo ka passivation liʻiliʻi a me ke kū'ē ʻana i ka corrosion haʻahaʻa i kēia manawa e pili ana i nā nanoislands waiwai Fe3+ kūloko kokoke i ka papa oxide Fe/Cr, hiki ke lilo i mau waiwai pale. Hoʻopau ka oxide i ka ʻili kiko a hoʻoulu i ka corrosion.
Ua loiloi mua ʻia ke ʻano corrosive o ka SDSS 2507 i hoʻololi ʻia me ka hoʻohana ʻana i nā ana electrochemical. Ma ke kiʻi. Hōʻike ka Kiʻi 1 i nā curve Nyquist a me Bode no nā laʻana i koho ʻia i loko o kahi hopena wai acidic (pH = 1) o FeCl3 ma ka mahana o ka lumi. Hana ka electrolyte i koho ʻia ma ke ʻano he mea oxidizing ikaika, e hōʻike ana i ke ʻano o ka ʻili passivation e haki. ʻOiai ʻaʻole i loaʻa ka mea i ka pitting paʻa ma ka mahana o ka lumi, ua hāʻawi ka loiloi i ka ʻike i nā hanana hāʻule hiki a me ka corrosion ma hope. Ua hoʻohana ʻia ke kaapuni like (Kiʻi 1d) e kūpono i ka spectrum electrochemical impedance spectroscopy (EIS), a ua hōʻike ʻia nā hopena kūpono e pili ana ma ka Papa 1. ʻIke ʻia nā semicircles piha ʻole i nā specimens i mālama ʻia me ka hopena a me nā hana wela, ʻoiai ʻike ʻia nā semicircles i hoʻopaʻa ʻia i nā hoa like i ʻōwili anu ʻia (Kiʻi .1b). Ma ka spectroscopy EIS, hiki ke noʻonoʻo ʻia ka radius o ka semicircle ʻo ia ke kū'ē polarization (Rp)25,26. ʻO ka Rp o ke ala holo i mālama ʻia me ka hopena ma ka Papa 1 ma kahi o 135 kΩ cm–2, akā naʻe, ʻoi aku ka haʻahaʻa o nā waiwai o ke ala holo i hana wela ʻia a me ke anu ʻōwili ʻia, 34.7 a me 2.1 kΩ cm–2, kēlā me kēia. Hōʻike kēia hōʻemi koʻikoʻi ma Rp i ka hopena maikaʻi ʻole o ka deformation plastic i ka passivation a me ke kūpaʻa ʻana i ka corrosion, e like me ka mea i hōʻike ʻia ma nā hōʻike mua27,28,29,30.
a ʻO Nyquist, b, c Bode impedance a me nā kiʻikuhi pae, a me d nā hiʻohiʻona kaapuni like e pili ana, kahi ʻo RS ke kū'ē electrolyte, ʻo Rp ke kū'ē polarization, a ʻo QCPE ka oxide o ka element pae mau i hoʻohana ʻia e hoʻohālike i ka capacitance kūpono ʻole (n). Hana ʻia nā ana EIS ma ka hiki ke kaapuni hāmama.
Hōʻike ʻia nā kūpaʻa like ma ka palapala Bode, me kahi plateau ma ka laulā alapine kiʻekiʻe e hōʻike ana i ke kū'ē electrolyte RS26. Ke emi nei ke alapine, piʻi ka impedance a loaʻa kahi kihi pae maikaʻi ʻole, e hōʻike ana i ka mana capacitance. Piʻi ka kihi pae, e mālama ana i ka nui ma luna o kahi laulā alapine ākea, a laila emi iho (Kiʻi 1c). Eia naʻe, i nā hihia ʻekolu, ʻoi aku ka liʻiliʻi o kēia nui ma mua o 90°, e hōʻike ana i ke ʻano capacitive maikaʻi ʻole ma muli o ka hoʻolaha capacitive. No laila, hoʻohana ʻia ka QCPE constant phase element (CPE) e hōʻike i nā hoʻolaha capacitance interfacial e kū mai ana mai ka ʻili o ka ʻili a i ʻole ka inhomogeneity, ʻoi aku hoʻi ma ka pae atomika, ka geometry fractal, ka porosity electrode, ka hiki ʻole ke like, a me ke geometry me ke ʻano o nā electrodes31,32. CPE impedance:
kahi ʻo j ka helu hoʻokalakupua a ʻo ω ka alapine angular. ʻO QCPE kahi alapine kūʻokoʻa mau e pili ana i ka ʻāpana hāmama maikaʻi o ka electrolyte. ʻO n kahi helu mana dimensionless e wehewehe ana i ka ʻokoʻa o kahi capacitor mai ka capacitance kūpono, ʻo ia hoʻi, ʻo ka kokoke o n i ka 1, ʻo ka kokoke o ka CPE i ka capacitive purely, ʻoiai inā kokoke ʻo n i ka zero, ʻike ʻia he resistive. ʻO nā ʻokoʻa liʻiliʻi o n, kokoke i ka 1, e hōʻike ana i ke ʻano capacitive maikaʻi ʻole o ka ʻili ma hope o nā hoʻāʻo polarization. ʻOi aku ke kiʻekiʻe o ka QCPE o ka SDSS i ʻōwili anu ʻia ma mua o kona mau hoa, ʻo ia hoʻi, ʻaʻole like ka maikaʻi o ka ʻili.
E kūlike me ka hapa nui o nā waiwai kūpaʻa i ka palaho o nā kila kila kila, ʻo ka nui o ka Cr o SDSS e hopena i ka kūpaʻa maikaʻi loa o SDSS ma muli o ke alo o kahi kiʻiʻoniʻoni pale oxide passivating ma luna o ka ʻili17. ʻO kēlā mau kiʻiʻoniʻoni passivating he waiwai nui ia i nā oxides Cr3+ a/a i ʻole hydroxides, ʻo ia hoʻi i ka hui pū ʻana me Fe2+, Fe3+ oxides a/a i ʻole (oxy)hydroxides33. ʻOiai ke ʻano like o ka ʻili, ka papa oxide passivating, a ʻaʻohe haki ʻili i ʻike ʻia e like me nā ana microscopic6,7, ʻokoʻa ke ʻano palaho o ka SDSS i hana wela ʻia a me ka SDSS i ʻōwili anu ʻia, no laila pono kahi noiʻi hohonu o nā ʻano microstructural no ka deformation kila.
Ua aʻo ʻia ka microstructure o ke kila kila deformed me ka hoʻohana ʻana i nā kukuna X-energy kiʻekiʻe intrinsic a me synchrotron (Nā Kiʻi Hoʻohui 1, 2). Hāʻawi ʻia kahi loiloi kikoʻī ma ka ʻIke Hoʻohui. ʻOiai aia kahi ʻaelike maʻamau e pili ana i ke ʻano o ka pae nui, ua loaʻa nā ʻokoʻa i nā ʻāpana pae nui, i helu ʻia ma ka Papa Hoʻohui 1. Hiki i kēia mau ʻokoʻa ke kumu o nā ʻāpana pae inhomogeneous ma ka ʻili a ma ka leo, i hoʻopilikia ʻia e nā hohonu ʻike diffraction X-ray (XRD) like ʻole. ) me nā kumu ikehu like ʻole o nā photons hanana34. ʻO nā ʻāpana austenite kiʻekiʻe i nā specimens i ʻōwili anu i hoʻoholo ʻia e XRD mai kahi kumu hale hana e hōʻike ana i ka passivation maikaʻi a laila ʻoi aku ka maikaʻi o ke kūpaʻa corrosion35, ʻoiai ʻoi aku ka pololei a me nā hopena helu e hōʻike ana i nā ʻano kūʻē i nā ʻāpana pae. Eia kekahi, ʻo ke kūpaʻa corrosion o ke kila e pili pū ana i ke kiʻekiʻe o ka hoʻomaʻemaʻe ʻana o ka palaoa, ka hōʻemi ʻana o ka nui o ka palaoa, ka hoʻonui ʻana i nā microdeformations a me ka dislocation density e hana ʻia i ka wā o ka mālama thermomechanical36,37,38. Ua hōʻike nā ʻano hana wela i kahi ʻano ʻoi aku ka nui o nā hua, e hōʻike ana i nā hua micron, ʻoiai ʻo nā apo laumania i ʻike ʻia i nā ʻano i ʻōwili anu ʻia (Kiʻi Hoʻohui 3) e hōʻike ana i ka hoʻomaʻemaʻe nui ʻana o ka hua i ka nanosize i ka hana ma mua. Pono kēia e ʻae i ka hoʻokumu ʻana o ka ʻili passive. a me ka hoʻonui ʻana o ke kū'ē ʻana i ka pala. ʻO ka nui o ka dislocation density e pili pinepine ʻia me ka haʻahaʻa o ke kū'ē ʻana i ka pitting, kahi e kūlike maikaʻi me nā ana electrochemical.
Ua aʻo ʻia nā loli i ke kūlana kemika o nā microdomains o nā mea nui me ka hoʻohana ʻana iā X-PEEM. ʻOiai he nui aku nā mea hoʻohuihui, ua koho ʻia ʻo Cr, Fe, Ni a me Ce39 ma ʻaneʻi, ʻoiai ʻo Cr ke kumu nui no ka hoʻokumu ʻana i ka ʻili passive, ʻo Fe ke kumu nui no ke kila, a hoʻonui ʻo Ni i ka passivation a kaulike i ka pae ferrite-austenitic. ʻO ke ʻano a me ka hoʻololi ʻana ke kumu o Ce. Ma ka hoʻonohonoho ʻana i ka ikehu kukuna synchrotron, ua hopu ʻo XAS i nā ʻano nui o Cr (ʻaoʻao L2.3), Fe (ʻaoʻao L2.3), Ni (ʻaoʻao L2.3), a me Ce (ʻaoʻao M4.5) mai ka ʻili. -2507 SDSS. Ua hana ʻia ka loiloi ʻikepili kūpono ma ka hoʻokomo ʻana i ka calibration ikehu me ka ʻikepili i paʻi ʻia (e laʻa me XAS ma Fe L2, 3 iwi ʻaoʻao40,41).
Ma ke kiʻi. Hōʻike ke Kiʻi 2 i nā kiʻi X-PEEM o ka hana wela (Kiʻi 2a) a me ka ʻōwili anu (Kiʻi 2d) Ce-2507 SDSS a me nā kihi XAS Cr a me Fe L2,3 e pili ana ma nā kūlana i hōʻailona ʻia. Ke ʻimi nei ka lihi L2,3 XAS i nā kūlana 3d ʻole o nā electrons ma hope o ka photoexcitation ma nā pae hoʻokaʻawale spin-orbit 2p3/2 (lihi L3) a me 2p1/2 (lihi L2). Ua loaʻa ka ʻike e pili ana i ke kūlana valence o Cr mai ka loiloi diffraction X-ray o ka lihi L2,3 ma ke Kiʻi 2b,d. Hoʻohālikelike loulou. Ua hōʻike ʻia ʻehā mau piko A (578.3 eV), B (579.5 eV), C (580.4 eV), a me D (582.2 eV) i ʻike ʻia ma kahi kokoke i ka lihi L3, e hōʻike ana i nā ion Cr3+ octahedral, Cr2O3 e pili ana. Ua kūlike nā spectra hoʻokolohua me nā helu kumumanaʻo, e like me ka mea i hōʻike ʻia ma nā panela b a me e, i loaʻa mai nā helu kahua kristal he nui ma ka interface Cr L2.3 me ka hoʻohana ʻana i kahi kahua kristal o 2.0 eV44. Ua uhi ʻia nā ʻili ʻelua o ka SDSS i hana wela ʻia a me ka SDSS i ʻōwili anu ʻia me kahi papa like o Cr2O3.
ʻO ke kiʻi wela o ka X-PEEM SDSS i hoʻokumu ʻia i ka wela e pili ana i ka lihi b Cr L2.3 a me ka lihi c Fe L2.3, d Kiʻi wela X-PEEM o ka SDSS i ʻōwili anu ʻia e pili ana i ka lihi e Cr L2.3 a me f Fe L2.3 o ka ʻaoʻao (e). Hōʻike nā spectra XAS i nā kūlana spatial like ʻole i hōʻailona ʻia ma nā kiʻi wela (a, d) e nā laina kiko ʻalani ma (b) a me (e) i nā spectra XAS i hoʻohālikelike ʻia o Cr3+ me kahi waiwai kahua kristal o 2.0 eV. No nā kiʻi X-PEEM, hoʻohana ʻia kahi palette wela e hoʻomaikaʻi i ka heluhelu ʻana o ke kiʻi, kahi e kūlike ai nā kala mai ka uliuli a i ka ʻulaʻula me ka ikaika o ka omo ʻana o ka X-ray (mai ka haʻahaʻa a i ke kiʻekiʻe).
Me ka nānā ʻole i ke kaiapuni kemika o kēia mau mea metala, ua like ke ʻano kemika o nā hoʻohui o nā mea hoʻohuihui Ni a me Ce no nā laʻana ʻelua. Kiʻi hou aʻe. Ma ke kiʻi. 5-9 e hōʻike i nā kiʻi X-PEEM a me nā spectra XAS e pili ana no Ni a me Ce ma nā wahi like ʻole ma ka ʻili o nā laʻana i hana wela ʻia a me nā laʻana i ʻōwili anu ʻia. Hōʻike ʻo Ni XAS i ke ʻano oxidation o Ni2+ ma luna o ka ʻili holoʻokoʻa i ana ʻia o nā laʻana i hana wela ʻia a me nā laʻana i ʻōwili anu ʻia (Kūkākūkā Hoʻohui). He mea kūpono ia i ka hihia o nā laʻana i hana wela ʻia, ʻaʻole ʻike ʻia ka hōʻailona XAS o Ce, ʻoiai ʻike ʻia ka spectrum o Ce3+ o nā laʻana i ʻōwili anu ʻia ma kekahi wahi. Ua hōʻike ka ʻike ʻana o nā kiko Ce i nā laʻana i ʻōwili anu ʻia aia ʻo Ce ma ke ʻano o nā precipitates.
I loko o ka SDSS i hoʻololi ʻia i ka wela, ʻaʻohe loli kūkulu kūloko ma XAS i ʻike ʻia ma ka lihi Fe L2.3 (Kiʻi 2c). Eia naʻe, e like me ka mea i hōʻike ʻia ma ke kiʻi 2f, hoʻololi ka matrix Fe i kona kūlana kemika ma ʻehiku mau wahi i koho ʻia ma ka SDSS i ʻōwili anu ʻia. Eia kekahi, i mea e loaʻa ai kahi manaʻo pololei o nā loli i ke kūlana o Fe ma nā wahi i koho ʻia ma ke Kiʻi 2f, ua hana ʻia nā haʻawina ʻili kūloko (Kiʻi 3 a me ke Kiʻi Hoʻohui 10) kahi i koho ʻia ai nā ʻāpana pōʻai liʻiliʻi. Ua hoʻohālikelike ʻia nā spectra XAS o ka lihi Fe L2,3 o nā ʻōnaehana α-Fe2O3 a me nā oxides octahedral Fe2+ me ka hoʻohana ʻana i nā helu kahua kristal multilet me ka hoʻohana ʻana i nā kahua kristal o 1.0 (Fe2+) a me 1.0 (Fe3+)44. Hoʻomaopopo mākou he ʻokoʻa nā symmetries kūloko o α-Fe2O3 a me γ-Fe2O345,46, loaʻa iā Fe3O4 ka hui pū ʻana o Fe2+ & Fe3+,47, a me FeO45 ma ke ʻano he Fe2+ oxide divalent formally (3d6). Hoʻomaopopo mākou he ʻokoʻa nā symmetries kūloko o α-Fe2O3 a me γ-Fe2O345,46, loaʻa iā Fe3O4 ka hui pū ʻana o Fe2+ & Fe3+,47, a me FeO45 ma ke ʻano he Fe2+ oxide divalent formally (3d6).E hoʻomaopopo he ʻokoʻa nā symmetries kūloko o α-Fe2O3 a me γ-Fe2O345,46, hoʻohui ʻo Fe3O4 iā Fe2+ a me Fe3+,47 a me FeO45 ma ke ʻano o ka oxide divalent formally Fe2+ (3d6).E hoʻomaopopo he ʻokoʻa nā symmetries kūloko o α-Fe2O3 a me γ-Fe2O345,46, loaʻa iā Fe3O4 nā hui pū ʻana o Fe2+ a me Fe3+,47 a hana ʻo FeO45 ma ke ʻano he oxide divalent formal Fe2+ (3d6). Loaʻa i nā ion Fe3+ āpau i loko o α-Fe2O3 nā kūlana Oh wale nō, ʻoiai ʻo γ-Fe2O3 e hōʻike pinepine ʻia ma ke ʻano he Fe3+ t2g [Fe3+5/3V1/3]eg O4 spinel me nā hakahaka i nā kūlana eg. No laila, loaʻa i nā ion Fe3+ i loko o γ-Fe2O3 nā kūlana Td a me Oh. E like me ka mea i ʻōlelo ʻia ma ka hana ma mua, ʻoiai he ʻokoʻa nā lakio ikaika o nā mea ʻelua, ʻo kā lākou lakio ikaika eg/t2g he ≈1, ʻoiai ma kēia hihia ʻo ka lakio ikaika i ʻike ʻia eg/t2g ma kahi o 1. Hoʻopau kēia i ka hiki ke loaʻa wale ʻo Fe3+ i kēia hihia. Ke noʻonoʻo nei i ka hihia o Fe3O4 me nā hui pū ʻana o Fe2+ a me Fe3+, ua ʻike ʻia ʻo kahi hiʻohiʻona mua nāwaliwali (ikaika) ma ka lihi L3 o Fe e hōʻike ana i kahi noho ʻole liʻiliʻi (nui aʻe) ma ke kūlana t2g. Pili kēia iā Fe2+ (Fe3+), e hōʻike ana i ka piʻi ʻana o ka hōʻailona mua e hōʻike ana i ka piʻi ʻana o ka ʻike o Fe2+47. Hōʻike kēia mau hopena ua lanakila ʻo Fe2+ a me γ-Fe2O3, α-Fe2O3 a/a i ʻole Fe3O4 ma luna o nā ʻili i ʻōwili anu ʻia o nā composites.
Nā kiʻi wela electron photoemission i hoʻonui ʻia o nā spectra (a, c) a me (b, d) XAS ma ka lihi Fe L2,3 ma nā kūlana spatial like ʻole i loko o nā ʻāpana i koho ʻia 2 a me E ma nā Kiʻi 2d.
Ua hoʻolālā ʻia nā ʻikepili hoʻokolohua i loaʻa (Kiʻi 4a a me ke Kiʻi Hoʻohui 11) a ua hoʻohālikelike ʻia me nā mea o nā hui maʻemaʻe 40, 41, 48. Ma ke kumu, ʻekolu mau ʻano like ʻole o nā spectra Fe L-edge XAS i nānā ʻia ma ka hoʻokolohua (XAS-1, XAS-2 a me XAS-3: Kiʻi 4a) i ʻike ʻia ma nā wahi like ʻole. Ma ke ʻano kūikawā, ua ʻike ʻia kahi spectrum e like me 2-a (i hōʻike ʻia ʻo XAS-1) ma ke Kiʻi 3b ma luna o ka ʻāpana hoihoi holoʻokoʻa, ukali ʻia e kahi spectrum 2-b (i kapa ʻia ʻo XAS-2), ʻoiai ua ʻike ʻia kahi spectrum e like me E-3 ma ke kiʻi 3d (i kapa ʻia ʻo XAS-3) ma kekahi mau wahi kūloko. ʻO ka maʻamau, ʻehā mau palena e hoʻohana ʻia e ʻike i nā kūlana valence i loaʻa i loko o kahi hāpana probe: (1) nā hiʻohiʻona spectral L3 a me L2, (2) nā kūlana ikehu o nā hiʻohiʻona L3 a me L2, (3) ka ʻokoʻa ikehu L3-L2, (4) ka lakio ikaika L2 /L3. Wahi a nā nānā ʻike maka (Kiʻi 4a), aia nā ʻāpana Fe ʻekolu, ʻo ia hoʻi ʻo Fe0, Fe2+, a me Fe3+, ma luna o ka ʻili o ka SDSS i aʻo ʻia. Ua hōʻike pū ka lakio ikaika i helu ʻia ʻo L2/L3 i ke alo o nā ʻāpana ʻekolu.
a Ua ʻike ʻia nā ʻikepili hoʻokolohua ʻekolu like ʻole (nā laina paʻa XAS-1, XAS-2 a me XAS-3 e pili ana iā 2-a, 2-b a me E-3 ma ke Kiʻi 2 a me ke Kiʻi 3) i hoʻohālikelike ʻia me nā spectra hoʻohālikelike XAS i hoʻohālikelike ʻia, nā octahedrons Fe2+, Fe3+, nā waiwai kahua kristal o 1.0 eV a me 1.5 eV, kēlā me kēia, b–d Ua ana ʻia nā ʻikepili hoʻokolohua (XAS-1, XAS-2, XAS-3) a me nā ʻikepili LCF i hoʻonui ʻia e pili ana (laina ʻeleʻele paʻa), a me ka hoʻohālikelike ʻana i nā spectra XAS-3 me nā kūlana Fe3O4 (kūlana hui o Fe) a me Fe2O3 (Fe3+ maʻemaʻe).
Ua hoʻohana ʻia kahi hui linear (LCF) o nā kūlana ʻekolu40,41,48 e helu i ka haku mele ʻana o ka hao oxide. Ua hoʻokō ʻia ʻo LCF no ʻekolu mau spectra Fe L-edge XAS i koho ʻia e hōʻike ana i ke ʻano ʻokoʻa kiʻekiʻe loa, ʻo ia hoʻi ʻo XAS-1, XAS-2 a me XAS-3, e like me ka mea i hōʻike ʻia ma ke Kiʻi 4b–d. No nā mea hoʻopili LCF, ua noʻonoʻo ʻia he 10% Fe0 i nā hihia āpau ma muli o ka lihi liʻiliʻi a mākou i ʻike ai ma nā ʻikepili āpau a me ka ʻoiaʻiʻo ʻo ka metala ferrous ka ʻāpana nui o ke kila. ʻOiaʻiʻo, ʻoi aku ka nui o ka hohonu o ka hoʻāʻo ʻana o X-PEEM no Fe (~ 6 nm) 49 ma mua o ka mānoanoa o ka papa oxidation i manaʻo ʻia (ʻoi aku ka nui ma mua o 4 nm), e ʻae ana i ka ʻike ʻana i ka hōʻailona mai ka matrix hao (Fe0) ma lalo o ka papa passivation. ʻOiaʻiʻo, ʻoi aku ka nui o ka hohonu o ka hoʻāʻo ʻana o X-PEEM no Fe (~ 6 nm) 49 ma mua o ka mānoanoa o ka papa oxidation i manaʻo ʻia (ʻoi aku ka nui ma mua o 4 nm), e ʻae ana i ka ʻike ʻana i ka hōʻailona mai ka matrix hao (Fe0) ma lalo o ka papa passivation. Действительно, пробная глубина X-PEEM для Fe (~ 6 нм)49 больше, чем предполагаемая толщина слоя окисленияго, > 4 ночпол обнаружить сигнал от железной матрицы (Fe0) под пассивирующим слоем. ʻOiaʻiʻo, ʻoi aku ka hohonu o ka probe X-PEEM no Fe (~6 nm)49 ma mua o ka mānoanoa i manaʻo ʻia o ka papa oxidation (ʻoi aku ka nui ma mua o 4 nm), e hiki ai ke ʻike i ka hōʻailona mai ka matrix hao (Fe0) ma lalo o ka papa passivation.ʻOiaʻiʻo, ʻike ʻo X-PEEM iā Fe (~6 nm)49 i ka hohonu ma mua o ka mānoanoa i manaʻo ʻia o ka papa oxide (ʻoi aku ma mua o 4 nm), e ʻae ana i ka ʻike ʻana i nā hōʻailona mai ka matrix hao (Fe0) ma lalo o ka papa passivation. Ua hana ʻia nā hui like ʻole o Fe2+ a me Fe3+ e ʻike i ka hopena maikaʻi loa no ka ʻikepili hoʻokolohua i ʻike ʻia. Ma ke kiʻi. Hōʻike ka Kiʻi 4b i ka hui pū ʻana o Fe2+ a me Fe3+ ma ka spectrum XAS-1, kahi kokoke nā ʻāpana o Fe2+ a me Fe3+, ma kahi o 45%, e hōʻike ana i kahi kūlana oxidation hui ʻia o Fe. ʻOiai no ka spectrum XAS-2, lilo ka pakeneka o Fe2+ a me Fe3+ i ~30% a me 60%, kēlā me kēia. ʻOi aku ka haʻahaʻa o ka ʻike o Fe2+ ma mua o Fe3+. ʻO ka lakio Fe2+ a i Fe3 o 1:2 ʻo ia hoʻi hiki ke hoʻokumu ʻia ʻo Fe3O4 ma ka lakio like o nā ion Fe. Eia kekahi, no ka XAS-3 spectrum, ua loli nā pakeneka o Fe2+ a me Fe3+ i ~10% a me 80%, e hōʻike ana i kahi hoʻololi kiʻekiʻe o Fe2+ i Fe3+. E like me ka mea i ʻōlelo ʻia ma luna, hiki iā Fe3+ ke hele mai mai α-Fe2O3, γ-Fe2O3 a i ʻole Fe3O4. No ka hoʻomaopopo ʻana i ke kumu kūpono loa o Fe3+, ua hoʻolālā ʻia nā spectra XAS-3 me nā kūlana Fe3+ like ʻole ma ke Kiʻi 4e e hōʻike ana i ke ʻano like me nā kūlana ʻelua āpau ke noʻonoʻo ʻia ʻo Peak B. Eia nō naʻe, ʻo ka ikaika o ka poʻohiwi (A: mai Fe2+) a me ka lakio ikaika B/A e hōʻike ana ua kokoke ka spectrum o XAS-3 akā ʻaʻole like me ko γ-Fe2O3. Ke hoʻohālikelike ʻia me ka bulk γ-Fe2O3, ʻoi aku ka kiʻekiʻe o ka ikaika Fe 2p XAS o ka piko A SDSS (Kiʻi 4e), e hōʻike ana i kahi ikaika Fe2+ kiʻekiʻe. ʻOiai ua like ke ʻano o ka spectrum o XAS-3 me ko γ-Fe2O3, kahi i loaʻa ai ʻo Fe3+ ma nā kūlana Oh a me Td, ʻo ka ʻike ʻana i nā kūlana valence like ʻole a me ka hoʻonohonoho ʻana ma o ka lihi L2,3 a i ʻole ka lakio ikaika L2/L3 he pilikia nō ia. he kumuhana kūkākūkā hou ma muli o ka paʻakikī o nā mea like ʻole i pili i ka spectrum hope loa41.
Ma waho aʻe o ka hoʻokaʻawale ʻana o nā ʻano kemika o nā wahi hoihoi i koho ʻia i wehewehe ʻia ma luna, ua loiloi ʻia ka heterogeneity kemika honua o nā mea nui ʻo Cr a me Fe ma ka hoʻokaʻawale ʻana i nā spectra XAS āpau i loaʻa ma ka ʻili o ka laʻana me ka hoʻohana ʻana i ke ʻano hui K-means. Ua hoʻonohonoho ʻia nā ʻaoʻao lihi Cr L i ke ʻano e hana ai i ʻelua mau hui kūpono i hoʻolaha ʻia ma kahi ākea i nā spectra i hana wela ʻia a me nā ʻōwili anu i hōʻike ʻia ma nā Kiʻi 5. Ua maopopo ʻaʻole i ʻike ʻia nā loli kūkulu kūloko, ʻoiai ua like loa nā centroids ʻelua o nā spectra XAS Cr. ʻAneʻane like kēia mau ʻano spectral o nā hui ʻelua me nā mea e pili ana iā Cr2O342, ʻo ia hoʻi, ua hoʻolaha like ʻia nā papa Cr2O3 ma luna o ka SDSS.
he hui o nā ʻāpana K-means L-edge Cr, b nā kikowaena XAS e pili ana. Nā hopena o ka hoʻohālikelike ʻana o K-means X-PEEM o ka SDSS i ʻōwili anu ʻia: c nā hui o nā ʻāpana K-means edge o Cr L2,3 a me d nā kikowaena XAS e pili ana.
No ka hoʻākāka ʻana i kahi palapala ʻāina lihi FeL paʻakikī, ʻehā a me ʻelima mau hui i hoʻomaikaʻi ʻia a me kā lākou mau centroids pili (nā hoʻolaha spectral) i hoʻohana ʻia no nā specimens i hana wela ʻia a me nā specimens i ʻōwili anu ʻia. No laila, hiki ke loaʻa ka pakeneka (%) o Fe2+ a me Fe3+ ma ka hoʻoponopono ʻana i ka LCF i hōʻike ʻia ma ke Kiʻi 4. ʻO ka pseudoelectrode potential Epsudo ma ke ʻano he hana o Fe0 ua hoʻohana ʻia e hōʻike i ka microchemical inhomogeneity o ka ʻili oxide film. Ua manaʻo ʻia ʻo Epsudo e ka lula hui ʻana,
kahi \(\rm{E}_{\rm{Fe}/\rm{Fe}^{2 + (3 + )}}\) e like me \(\rm{Fe} + 2e^ – \to\rm { Fe}^{2 + (3 + )}\), ʻo ia hoʻi he 0.440 a me 0.036 V, kēlā me kēia. ʻO nā wahi me ka hiki ke haʻahaʻa he ʻoi aku ka nui o nā hui Fe3+. ʻO ka hoʻolaha hiki i loko o kahi hāpana i hoʻololi ʻia i ka thermally he ʻano papa me ka loli nui loa ma kahi o 0.119 V (Kiʻi 6a,b). Pili loa kēia hoʻolaha hiki i ka topography ʻili (Kiʻi 6a). ʻAʻohe loli ʻē aʻe e pili ana i ke kūlana i ʻike ʻia ma loko o ka lamellar ma lalo (Kiʻi 6b). Ma ke ʻano ʻē, no ka hui pū ʻana o nā oxides like ʻole me nā ʻike like ʻole o Fe2+ a me Fe3+ i loko o ka SDSS i ʻōwili anu ʻia, hiki ke ʻike ʻia kahi ʻano like ʻole o ka pseudopotential (Kiʻi 6c, d). ʻO nā oxides Fe3+ a/a i ʻole (oxy)hydroxides nā ʻāpana nui o ka palaho i ke kila a he permeable i ka oxygen a me ka wai50. I kēia hihia, hiki ke ʻike ʻia ua hoʻolaha ʻia nā mokupuni waiwai i ka Fe3+ ma kahi kūloko a hiki ke manaʻo ʻia he mau wahi palaho. I kēia hihia, ʻo ka gradient i ke kahua hiki, ma mua o ka waiwai paʻa o ka hiki, hiki ke manaʻo ʻia he hōʻailona no ka localization o nā wahi palaho hana51. ʻO kēia hoʻolaha inhomogeneous o Fe2+ a me Fe3+ ma ka ʻili o ka SDSS i ʻōwili anu ʻia hiki ke hoʻololi i nā waiwai kemika kūloko a hāʻawi i kahi ʻili ʻoi aku ka maikaʻi i ka haki ʻana o ka ʻili oxide a me nā hopena palaho, no laila e ʻae ana i ka matrix metala ma lalo e palaho mau, e hopena ana i ka inhomogeneity kūloko. a hoʻemi i nā ʻano pale o ka papa passivating.
ʻO nā hui K-mean o nā ʻāpana lihi Fe L2,3 a me nā centroids XAS e pili ana no a-c X-PEEM i hana wela ʻia a me d-f SDSS i ʻōwili anu ʻia. a, d K-means cluster plot i uhi ʻia ma ke kiʻi X-PEEM. Ua ʻōlelo ʻia nā potentials pseudoelectrode i manaʻo ʻia (epseudo) me nā kiʻikuhi hui K-means. ʻO ka ʻōlinolino o kahi kiʻi X-PEEM e like me ke kala ma ke Kiʻi 2 ua kūlike pololei ia me ka ikaika o ka omo ʻana o ka X-ray.
ʻO ke ʻano like ʻole o Cr akā ʻokoʻa ke kūlana kemika o Fe e alakaʻi ai i kahi kumu like ʻole o ka haki ʻana o ka ʻili oxide a me nā ʻano palaho i ka Ce-2507 i ʻōwili wela ʻia a me ka ʻōwili anu. Ua ʻike maikaʻi ʻia kēia ʻano o Ce-2507 i ʻōwili anu ʻia. E pili ana i ka hoʻokumu ʻia ʻana o nā oxides a me nā hydroxides o Fe i ka lewa lewa, ua pani ʻia nā hopena aʻe ma kēia hana ma ke ʻano he mau hopena kūlike ʻole:
Ma muli o ke ana ʻana o X-PEEM, ua hana ʻia ka hopena ma luna ma nā hihia aʻe. ʻO kahi poʻohiwi liʻiliʻi e pili ana iā Fe0 e pili ana me ka hao metala ma lalo. ʻO ka hopena o ka metala Fe me ke kaiapuni e alakaʻi ai i ka hoʻokumu ʻia ʻana o kahi papa Fe(OH)2 (equation (5)), kahi e hoʻonui ai i ka hōʻailona Fe2+ ma ka XAS o ka lihi L o Fe. ʻO ka lōʻihi o ka hoʻopili ʻana i ka ea e hopena i ka hoʻokumu ʻia ʻana o Fe3O4 a/a i ʻole Fe2O3 oxides ma hope o Fe(OH)252,53. ʻElua ʻano o ka Fe paʻa, ʻo Fe3O4 a me Fe2O3, hiki ke hana i loko o kahi papa pale waiwai Cr3+, kahi e makemake ai ʻo Fe3O4 i kahi ʻano like a paʻa. ʻO ka loaʻa ʻana o nā mea ʻelua e hopena i nā kūlana oxidation hui ʻia (XAS-1 spectrum). ʻO ka XAS-2 spectrum e pili nui ana iā Fe3O4. ʻOiai ʻo nā spectra XAS-3 i ʻike ʻia ma kekahi mau kūlana i hōʻike i ka hoʻololi piha ʻana i γ-Fe2O3. ʻOiai ʻo ka hohonu o ke komo ʻana o nā kukuna X i wahī ʻole ʻia ma kahi o 50 nm, ʻo ka hōʻailona mai ka papa lalo e hopena i ka ikaika kiʻekiʻe o ka piko A.
Hōʻike ka spectrum XRD he ʻano papa ko ka ʻāpana Fe i loko o ka ʻili oxide, kahi i hui pū ʻia me ka papa Cr oxide. I ka hoʻohālikelike ʻana i ke ʻano passivation o ka corrosion ma muli o ka inhomogeneity kūloko o Cr2O317, ʻoiai ke ʻano like o ka papa o Cr2O3 i kēia haʻawina, ua ʻike ʻia ke kūpaʻa haʻahaʻa o ka corrosion ma kēia hihia, ʻoi aku hoʻi no nā laʻana i ʻōwili anu ʻia. Hiki ke hoʻomaopopo ʻia ke ʻano i ʻike ʻia ʻo ia ka heterogeneity o ke kūlana oxidation kemika o ka papa luna (Fe) e hoʻopilikia ana i ka hana corrosion. ʻO ka hoʻoili lohi o nā ion metala a i ʻole oxygen i loko o ka lattice ma muli o ka stoichiometry like o nā papa luna (Fe oxide) a me nā papa haʻahaʻa (Cr oxide)52,53 e alakaʻi ai i ka launa pū ʻana (adhesion) ma waena o lākou. ʻO kēia, ma ka huli ʻana, hoʻomaikaʻi i ke kūpaʻa corrosion. No laila, ʻoi aku ka maikaʻi o ka stoichiometry hoʻomau, ʻo ia hoʻi hoʻokahi kūlana oxidation o Fe, ma mua o nā loli stoichiometric koke. ʻOi aku ka like o ka ʻili o ka SDSS i hoʻololi ʻia i ka thermally a me kahi papa pale denser, e hāʻawi ana i ke kūpaʻa corrosion maikaʻi. Eia nō naʻe, no ka SDSS i ʻōwili anu ʻia, ʻo ke alo o nā mokupuni waiwai Fe3+ ma lalo o ka papa pale e hoʻopau i ka pono o ka ʻili a hoʻoulu i ka pala galvanic o ka substrate kokoke, kahi e alakaʻi ai i ka emi ʻana o Rp (Papa 1) i loko o nā spectra EIS a me kona pale ʻana i ka pala. No laila, ʻo nā mokupuni i hoʻolaha ʻia ma kahi kūloko i waiwai i ka Fe3+ ma muli o ka deformation plastic e hoʻopilikia nui i ka hana pale ʻana i ka pala, he holomua ia i kēia hana. No laila, hōʻike kēia haʻawina i nā spectromicrographs o ka emi ʻana o ke kūpaʻa ʻana i ka pala ma muli o ka deformation plastic o nā laʻana SDSS i aʻo ʻia.
Eia kekahi, ʻoiai ʻoi aku ka maikaʻi o ka hoʻohuihui honua laha ʻole i nā kila pae pālua, ʻo ka pilina o kēia mea i hoʻohui ʻia me ka matrix kila pākahi ma ke ʻano o ke ʻano corrosion e mau ana ka paʻakikī ma muli o nā nānā ʻana o ka microscopy spectroscopic. ʻIke wale ʻia ka hōʻailona Ce (ma ka ʻaoʻao XAS M) ma kekahi mau kūlana i ka wā o ka ʻōwili anu, akā nalo i ka wā o ka deformation wela o ka SDSS, e hōʻike ana i ka waiho kūloko o Ce i loko o ka matrix kila ma kahi o ka homogeneous alloying. ʻOiai ʻaʻole i hoʻomaikaʻi ʻia nā waiwai mechanical o SDSS6,7, ʻo ka loaʻa ʻana o REE e hōʻemi i ka nui o nā inclusions a ua manaʻo ʻia e kāohi i ka pitting ma ke kumu54.
I ka hopena, hōʻike kēia hana i ka hopena o ka heterogeneity o ka ʻili ma ka corrosion o 2507 SDSS i hoʻololi ʻia me ka cerium ma ka helu ʻana i ka ʻike kemika o nā ʻāpana nanoscale. Ua pane mākou i ka nīnau no ke aha e corrodes ai ke kila kila ʻoiai ke uhi ʻia me kahi papa oxide pale ma ke aʻo ʻana i ka microstructure, ke kūlana kemika o nā hiʻohiʻona o ka ʻili a me ka hana hōʻailona me ka hoʻohana ʻana i ka K-means clustering. Ua hoʻokumu ʻia ʻo nā mokupuni waiwai Fe3+, me ko lākou octahedral a me ka tetrahedral coordination ma o ke ʻano o ka hui ʻana o Fe2+/Fe3+, he kumu ia o ka luku ʻia ʻana o ka oxide film a me ke kumu o ka corrosion o ka SDSS i ʻōwili anu ʻia. ʻO nā Nanoislands i hoʻomalu ʻia e Fe3+ e alakaʻi i ka pale ʻino maikaʻi ʻole ʻoiai ke alo o kahi papa passivating Cr2O3 stoichiometric lawa. Ma waho aʻe o nā holomua methodological i hana ʻia i ka hoʻoholo ʻana i ka hopena o ka heterogeneity kemika nanoscale ma ka corrosion, manaʻo ʻia ka hana o kēia manawa e hoʻoulu i nā kaʻina hana ʻenekinia e hoʻomaikaʻi i ke kūpaʻa corrosion o nā kila kila i ka wā o ka hana kila.
No ka hoʻomākaukau ʻana i nā ingots Ce-2507 SDSS i hoʻohana ʻia ma kēia haʻawina, ua hoʻoheheʻe ʻia nā ʻāpana i hui ʻia, me ka Fe-Ce master alloy i hoʻopaʻa ʻia me nā paipu hao maʻemaʻe, i loko o ka umu hoʻokomo alapine waena 150 kg e hana i ke kila i hoʻoheheʻe ʻia a ninini ʻia i loko o nā ʻōmole hoʻolei. Ua helu ʻia nā ʻano kemika i ana ʻia (wt%) ma ka Papa Hoʻohui 2. Hoʻokumu mua ʻia ka ingot i loko o nā poloka. A laila ua hoʻomehana ʻia ke kila ma 1050°C no 60 mau minuke i kahi hopena paʻa, a laila hoʻopau ʻia i ka wai a hiki i ka mahana o ka lumi. Ua aʻo kikoʻī ʻia nā laʻana i aʻo ʻia me ka hoʻohana ʻana iā TEM a me DOE e aʻo i nā pae, ka nui o ka palaoa a me ke ʻano. Hiki ke loaʻa ka ʻike kikoʻī e pili ana i nā laʻana a me ke kaʻina hana ma nā kumu ʻē aʻe6,7.
E hana i nā laʻana cylinder (φ10 mm × 15 mm) no ke kaomi wela me ke axis o ka cylinder e like me ke kuhikuhi deformation o ka poloka. Ua hana ʻia ke kaomi wela kiʻekiʻe ma kahi helu strain mau ma ka pae o 0.01-10 s-1 ma nā mahana like ʻole ma ka pae o 1000-1150°C me ka hoʻohana ʻana i kahi simulator thermal Gleeble-3800. Ma mua o ke deformation, ua hoʻomehana ʻia nā laʻana ma ka mahana i koho ʻia ma ka helu o 10 °C s-1 no 2 min e hoʻopau i ka gradient mahana. Ma hope o ka hoʻokō ʻana i ke ʻano like o ka mahana, ua deformed nā laʻana i kahi waiwai strain maoli o 0.7. Ma hope o ke deformation, ua kinai koke ʻia me ka wai e mālama i ke ʻano deformed. A laila ua ʻoki ʻia nā specimens paʻakikī e like me ke kuhikuhi o ke kaomi ʻana. No kēia haʻawina kikoʻī, ua koho mākou i kahi specimen i deformed thermally ma 1050°C, 10 s-1 ma muli o kahi microhardness i ʻike ʻia ma mua o nā specimens ʻē aʻe7.
Ua hoʻāʻo ʻia nā laʻana nui (80 × 10 × 17 mm3) o ka hopena paʻa Ce-2507 ma kahi mīkini hoʻololi ʻelua-ʻōwili asynchronous ʻekolu-pae LG-300, nāna i hāʻawi i nā waiwai mechanical maikaʻi loa ma waena o nā papa hoʻololi ʻē aʻe āpau6. ʻO ka helu hoʻoluhi a me ka hoʻemi ʻana o ka mānoanoa he 0.2 m·s-1 a me 5% no kēlā me kēia ala, kēlā me kēia.
Ua hoʻohana ʻia kahi kahua hana electrochemical Autolab PGSTAT128N e ana i ka SDSS ma hope o ka ʻōwili anu ʻana i ka 90% o ka hoʻemi ʻana o ka mānoanoa (1.0 like ʻoiaʻiʻo like) a me ke kaomi wela ʻana i ka 0.7 ʻoiaʻiʻo ma 1050 oC a me 10 s-1. Loaʻa i ka kahua hana kahi cell electrode ʻekolu me kahi electrode calomel saturated ma ke ʻano he electrode kuhikuhi, kahi electrode counter graphite, a me kahi laʻana SDSS ma ke ʻano he electrode hana. Ua ʻoki ʻia nā laʻana i loko o nā cylinders me ke anawaena o 11.3 mm, i nā ʻaoʻao i hoʻopaʻa ʻia ai nā uea keleawe. A laila ua ninini ʻia ka laʻana me ka epoxy resin, e waiho ana i kahi ākea hana o 1 cm2 ma ke ʻano he electrode hana (ka ʻili haʻahaʻa o ka laʻana cylindrical). E akahele i ka wā e hoʻōla ai i ka epoxy a i ka wā e one ai a me ka polishing ma hope e pale aku i ka haki ʻana. Hoʻopaʻa ʻia ka ʻili hana a poli ʻia me kahi hoʻokuʻu poli daimana me ka nui o ka ʻāpana o 1 micron, hoʻomaʻemaʻe ʻia me ka wai distilled a me ka ethanol a hoʻomaloʻo ʻia i ka ea anuanu. Ma mua o nā ana electrochemical, ua hōʻike ʻia nā laʻana poli i ka ea no kekahi mau lā e hana i kahi kiʻiʻoniʻoni oxide kūlohelohe. Ua hoʻohana ʻia kahi hopena wai o FeCl3 (6.0 wt.%), i hoʻopaʻa ʻia me HCl i ka pH = 1.0 ± 0.01, e hoʻolalelale i ka pala o ke kila kila 55, ʻoiai ua loaʻa ia i nā wahi hoʻonāukiuki kahi i loaʻa ai nā ion chloride me ka mana oxidizing ikaika a me ka pH haʻahaʻa e like me ka mea i kuhikuhi ʻia e ASTM. ʻO nā kūlana i manaʻo ʻia ʻo G48 a me A923. Ua hoʻokomo ʻia nā laʻana i loko o ka hopena hoʻāʻo no 1 hola ma mua o ka lawe ʻia ʻana o kekahi mau ana i mea e hiki ai i kahi mokuʻāina kokoke i ka paʻa. No ka hopena paʻa, nā specimens i hana wela ʻia a me nā specimens i ʻōwili anu ʻia, ʻo ka laulā alapine ana impedance he 1 × 105 ~ 0.1 Hz, a ʻo ka hiki ke wehe ʻia ke kaapuni (OPS) he 5 mV, ʻo ia hoʻi he 0.39, 0.33, a me 0.25 VSCE, kēlā me kēia. Ua hana hou ʻia kēlā me kēia hoʻāʻo electrochemical o kekahi laʻana ma ka liʻiliʻi ʻekolu mau manawa ma lalo o nā kūlana like e hōʻoia i ka hana hou ʻana o ka ʻikepili.
No nā ana HE-SXRD, ua ana ʻia nā poloka kila duplex rectangular 1 × 1 × 1.5 mm3 ma kahi laina wiggler Brockhouse ikehu kiʻekiʻe ma CLS, Kanada e helu i ka haku mele ʻana o ka pae56. Ua hana ʻia ka hōʻiliʻili ʻikepili ma ka mahana o ka lumi ma ke ʻano geometry Debye-Scherrer a i ʻole ke ʻano geometry halihali. ʻO ka nalu o nā kukuna X i hoʻoponopono ʻia i ka calibrant LaB6 he 0.212561 Å, e kūlike ana me 58 keV, ʻoi aku ka kiʻekiʻe ma mua o Cu Kα (8 keV) i hoʻohana pinepine ʻia ma ke ʻano he kumu X-ray hale hana. Hoʻonoho ʻia ka laʻana ma kahi mamao o 740 mm mai ka mea ʻike. ʻO ka nui o ka ʻike o kēlā me kēia laʻana he 0.2 × 0.3 × 1.5 mm3, i hoʻoholo ʻia e ka nui o ke kukuna a me ka mānoanoa o ka laʻana. Ua hōʻiliʻili ʻia kēlā me kēia ʻikepili me ka hoʻohana ʻana i kahi mea ʻike wahi ʻo Perkin Elmer, mea ʻike X-ray panel pālahalaha, 200 µm pikela, 40 × 40 cm2, me ka hoʻohana ʻana i ka manawa hōʻike o 0.3 kekona a me 120 mau mōlina.
Ua hoʻokō ʻia nā ana X-PEEM o ʻelua mau ʻōnaehana hoʻohālike i koho ʻia ma ke kahua hopena PEEM o ka laina Beamline MAXPEEM ma ka hale hana MAX IV (Lund, Sweden). Ua hoʻomākaukau ʻia nā laʻana ma ke ʻano like me nā ana electrochemical. Ua mālama ʻia nā laʻana i hoʻomākaukau ʻia i ka lewa no kekahi mau lā a ua hoʻohemo ʻia ke kinoea i loko o kahi keʻena vacuum ultrahigh ma mua o ka hoʻomālamalama ʻia ʻana me nā photons synchrotron. Loaʻa ka hoʻonā ikehu o ke kukuna ma ke ana ʻana i ka spectrum output ion mai N 1 s a i 1\(\pi _g^ \ast\) o ka ʻāpana hoʻonāukiuki me hv = 401 eV ma N2 a me ka hilinaʻi o ka ikehu photon ma E3/2.57. Ua hāʻawi ka spectral fit iā ΔE (spectral linewidth) ~0.3 eV ma luna o ka pae ikehu i ana ʻia. No laila, ua manaʻo ʻia ka hoʻonā ikehu beamline ʻo E/∆E = 700 eV/0.3 eV > 2000 a me ka flux ≈1012 ph/s ma ka hoʻohana ʻana i kahi monochromator SX-700 i hoʻololi ʻia me kahi grating Si 1200-line mm−1 no ka lihi Fe 2p L2,3, ka lihi Cr 2p L2,3, ka lihi Ni 2p L2,3, a me ka lihi Ce M4,5. No laila, ua manaʻo ʻia ka hoʻonā ikehu beamline ʻo E/∆E = 700 eV/0.3 eV > 2000 a me ka flux ≈1012 ph/s ma ka hoʻohana ʻana i kahi monochromator SX-700 i hoʻololi ʻia me kahi grating Si 1200-line mm−1 no ka lihi Fe 2p L2.3, ka lihi Cr 2p L2.3, ka lihi Ni 2p L2.3, a me ka lihi Ce M4.5. Таким образом, энергетическое разрешение канала пучка было оценено как E/∆E = 700 эВ/0,3 эВ > 2000 и/10ф ≤ LIKE LIKE LIKE LIKE кромка Ce M4,5. No laila, ua manaʻo ʻia ka hoʻonā ikehu o ke kahawai kukuna e like me E/∆E = 700 eV/0.3 eV > 2000 a me ka flux ≈1012 f/s me ka hoʻohana ʻana i kahi monochromator SX-700 i hoʻololi ʻia me kahi grating Si o 1200 laina/mm no ka lihi Fe 2p L2,3, ka lihi Cr 2p L2.3, ka lihi Ni 2p L2.3, a me ka lihi Ce 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 通过使甿甛单色器和Si 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C。因此 ， 光束线 能量 分辨率 为 为 为 为 δe = 700 EV/0.3 EV> 2000 和 ≈1012 PH/S 通进 700 EV/0.3 EV单色器 和 SI 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 边缘缘、Cr 2p L2.3 边缘、Ni 2p L2.3 边缘缘。No laila, i ka wā e hoʻohana ai i kahi monochromator SX-700 i hoʻololi ʻia a me kahi grating Si laina 1200. 3, Cr edge 2p L2.3, Ni edge 2p L2.3 a me Ce edge M4.5.E hoʻonui i ka ikehu photon i nā ʻanuʻu 0.2 eV. I kēlā me kēia ikehu, ua hoʻopaʻa ʻia nā kiʻi PEEM me ka hoʻohana ʻana i kahi mea ʻike TVIPS F-216 CMOS me kahi pilina fiber optic binning 2 x 2 e hāʻawi ana i 1024 × 1024 mau pikela i loko o kahi kahua ʻike 20 µm. ʻO ka manawa hōʻike o nā kiʻi he 0.2 kekona, me ka awelika o 16 mau kiʻi. Ua koho ʻia ka ikehu kiʻi photoelectron i ke ʻano e hāʻawi ai i ka hōʻailona electron lua kiʻekiʻe loa. Hana ʻia nā ana āpau ma ka hanana maʻamau o kahi kukuna photon polarized linearly. No ka ʻike hou aku e pili ana i nā ana, e ʻike i kahi noiʻi ma mua58. Ma hope o ke aʻo ʻana i ke ʻano ʻike o ka huina electron yield (TEY)59 a me kāna noi ma X-PEEM, ua manaʻo ʻia ka hohonu ʻike o kēia ʻano hana ma ~4-5 nm no ka hōʻailona Cr a me ~6 nm no ka hōʻailona Fe. Ua kokoke loa ka hohonu Cr i ka mānoanoa o ka ʻili oxide (~4 nm)60,61 ʻoiai ʻoi aku ka nui o ka hohonu Fe ma mua o ka mānoanoa o ka ʻili oxide. ʻO ka XAS i hōʻiliʻili ʻia ma kahi kokoke i ka lihi Fe L he hui ʻana ia o ka hao oxide XAS a me FeO mai ka matrix. I ka hihia mua, ʻo ka ikaika o nā electrons i hoʻopuka ʻia ma muli o nā ʻano electrons āpau e hāʻawi ana iā TEY. Eia nō naʻe, pono ka hōʻailona hao maʻemaʻe i ka ikehu kinetic kiʻekiʻe no nā electrons e hele ma waena o ka papa oxide, hiki i ka ʻili, a hōʻiliʻili ʻia e ka mea kālailai. I kēia hihia, ʻo ka hōʻailona Fe0 ma muli nui o nā electrons LVV Auger a me nā electrons lua i hoʻopuka ʻia e lākou. Eia kekahi, ʻo ka ikaika TEY i hāʻawi ʻia e kēia mau electrons e palaho ana i ka wā o ke ala pakele electron49 e hōʻemi hou ana i ka pūlima spectral o Fe0 ma ka palapala ʻāina hao XAS.
ʻO ka hoʻohui ʻana i ka ʻeli ʻikepili i loko o nā cubes ʻikepili (ʻikepili X-PEEM) kahi hana koʻikoʻi i ka unuhi ʻana i ka ʻike pili (nā waiwai kemika a kino paha) ma ke ʻano multidimensional. Hoʻohana nui ʻia ka hui ʻana o K-means ma nā wahi he nui, me ka ʻike mīkini, ka hana kiʻi, ka ʻike ʻana i ke ʻano i nānā ʻole ʻia, ka naʻauao artificial, a me ka nānā ʻana i ka hoʻokaʻawale ʻana24. No ka laʻana, ua hoʻopili maikaʻi ʻia ka hui ʻana o K-means i ka hui ʻana i ka ʻikepili kiʻi hyperspectral62. Ma ke kumumanaʻo, no ka ʻikepili multi-object, hiki i ka algorithm K-means ke hoʻohui maʻalahi iā lākou e like me ka ʻike e pili ana i ko lākou mau ʻano (nā ʻano ikehu photon). ʻO ka hui ʻana o K-means kahi algorithm iterative no ka hoʻokaʻawale ʻana i ka ʻikepili i loko o nā hui K non-overlapping (nā hui), kahi e pili ai kēlā me kēia pixel i kahi hui kikoʻī ma muli o ka hoʻolaha spatial o ka inhomogeneity kemika i loko o ka haku mele microstructural kila. Aia ka algorithm K-means i ʻelua mau ʻanuʻu: ʻo ka hana mua e helu i nā K centroids, a ʻo ka hana ʻelua e hāʻawi i kēlā me kēia kiko i kahi hui me nā centroids kokoke. Ua wehewehe ʻia ke kikowaena o ke koʻikoʻi o kahi hui ʻo ia ka awelika helu o nā kiko ʻikepili (XAS spectra) o kēlā hui. Aia nā mamao like ʻole e wehewehe i nā centroids kokoke e like me nā mamao Euclidean. No kahi kiʻi hoʻokomo o px,y (ʻo x a me y ka hoʻonā ma nā pikela), ʻo CK ke kikowaena o ke koʻikoʻi o ka hui; a laila hiki ke hoʻokaʻawale ʻia kēia kiʻi (hui ʻia) i loko o nā hui K me ka hoʻohana ʻana iā K-means63. ʻO nā ʻanuʻu hope loa o ka algorithm clustering K-means:
KaʻAnuʻu Hana 2. E helu i ke kekelē o ka lālā o nā pikela āpau e like me ke kikowaena o kēia manawa. No ka laʻana, ua helu ʻia mai ka mamao Euclidean d ma waena o ke kikowaena a me kēlā me kēia pikela:
KaʻAnuʻu Hana 3 E hāʻawi i kēlā me kēia pikela i ka centroid kokoke loa. A laila e helu hou i nā kūlana K centroid penei:
KaʻAnuʻu Hana 4. E hana hou i ke kaʻina hana (nā kaulike (7) a me (8)) a hiki i ka hui ʻana o nā centroids. Pili loa nā hopena maikaʻi o ka hui hope loa me ke koho kūpono o nā centroids mua63. No ka hoʻonohonoho ʻikepili PEEM o nā kiʻi kila, ʻo X (x × y × λ) ma ke ʻano maʻamau he cube o ka ʻikepili array 3D, ʻoiai ʻo nā axis x a me y e hōʻike ana i ka ʻike spatial (hoʻonā pixel) a ʻo ke axis λ e pili ana i ke ʻano spectral ikehu o nā photons. Ua hoʻohana ʻia ka algorithm K-means e ʻimi i nā wahi hoihoi i ka ʻikepili X-PEEM ma ka hoʻokaʻawale ʻana i nā pixels (nā hui a i ʻole nā ​​​​​​sub-blocks) e like me kā lākou ʻano spectral a me ka unuhi ʻana i ka centroid maikaʻi loa (XAS spectral curve) no kēlā me kēia analyte (hui). Hoʻohana ʻia ia e aʻo i ka hoʻolaha spatial, nā loli spectral kūloko, ke ʻano oxidation a me ke kūlana kemika. No ka laʻana, ua hoʻohana ʻia ka algorithm clustering K-means no nā ʻāpana Fe L-edge a me Cr L-edge ma ka X-PEEM i hana wela ʻia a me ke anu. Ua hoʻāʻo ʻia nā helu like ʻole o nā K-clusters (nā ʻāpana microstructural) e ʻike i nā clusters a me nā centroids maikaʻi loa. Ke hōʻike ʻia ka pakuhi, ua hoʻololi hou ʻia nā pikela i nā centroids cluster kūpono. Pili kēlā me kēia hoʻolaha kala i ke kikowaena o ka cluster, e hōʻike ana i ka hoʻonohonoho spatial o nā mea kemika a i ʻole nā ​​​​mea kino. ʻO nā centroids i unuhi ʻia he mau hui linear o nā spectra maʻemaʻe.
Loaʻa nā ʻikepili e kākoʻo ana i nā hopena o kēia haʻawina mai ka mea kākau WC pili pono ma ke noi kūpono.
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