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ʻO ke kila kila kila i hoʻohana nui ʻia a me kāna mau ʻano hana i kū i ka corrosion i nā kūlana ambient ma muli o ka papa passivation i loko o ka chromium oxide. Hoʻopili pinepine ʻia ka ʻino a me ka ʻino ʻana o ke kila me ka luku ʻana i kēia mau papa, akā ʻaʻole kakaikahi me ke ʻano o ka like ʻole o ka ʻili, ma muli o ka pae microscopic. Ma keia hana, nanoscale chemical surface heterogeneity, ike ia e spectroscopic microscopy a me chemometric analysis, unexpected dominate the fracture and corrosion o ke anuanu olokaʻi cerium hoʻololi super duplex kuhiliʻole kila 2507 (SDSS) i kona wela deformation. ʻOiai ua hōʻike ʻo X-ray photoelectron microscopy i kahi uhi ʻokoʻa o ka papa Cr2O3 maoli, ʻaʻole maikaʻi ka hana passivation o ka SDSS i ʻōwili ʻia ma muli o ka hoʻohele kūloko o Fe3 + waiwai nanoislands ma ka papa Fe/Cr oxide. Hāʻawi kēia ʻike unahi atomika i ka ʻike hohonu o ka ʻino kila kila a manaʻo ʻia e kōkua i ka hakakā ʻana i ka ʻino o nā metala kiʻekiʻe like.
Mai ka hana ʻana o ke kila kila, ua hoʻoili ʻia nā waiwai anti-corrosion o ferrochrome i ka chromium, ka mea i hana i nā oxides/oxyhydroxides ikaika a hōʻike i kahi ʻano passivating i ka hapa nui o nā kaiapuni. Ke hoʻohālikelike ʻia me nā kila kuhili ʻole (austenitic a me ferritic) 1, 2, 3, ʻoi aku ka maikaʻi o ka pale ʻana i ka corrosion a me nā waiwai mechanical maikaʻi loa. ʻO ka hoʻonui ʻana i ka ikaika mechanical e hiki ai i nā hoʻolālā māmā a paʻakikī. ʻO ka ʻokoʻa, ʻoi aku ka nui o ka pale ʻana o ka SDSS waiwai i ka pitting a me ka crevice corrosion, ka hopena o ke ola lawelawe ʻoi aku ka lōʻihi, a laila e hoʻonui ai i kāna noi i ka hoʻomalu ʻana i ka haumia, nā ipu kemika, a me ka ʻoihana ʻaila a me ke kinoea waho4. Eia nō naʻe, ʻo ka haʻikiʻi o nā mahana lapaʻau wela a me ka maikaʻi ʻole o ka formability ke keʻakeʻa nei i kā lākou hoʻohana ākea. No laila, hoʻololi ʻia ka SDSS e hoʻomaikaʻi i ka hana ma luna. Eia kekahi laʻana, ua hoʻokomoʻia ka hoʻololi Ce i SDSS 2507 (Ce-2507) me kahi mea nui nitrogen content6,7,8. He hopena maikaʻi ka ʻeleʻele honua laʻe (Ce) ma kahi ʻano kūpono o 0.08 wt.% i nā waiwai mechanical o ka DSS, no ka mea, hoʻomaikaʻi ʻo ia i ka hoʻomaʻemaʻe palaoa a me ka ikaika palena o ka palaoa. Hoʻomaikaʻi ʻia ka hana ʻana a me ka corrosion, ka ikaika tensile a me ka hoʻoulu ʻana, a me ka hana wela. Hiki i ka nui o ka nitrogen ke hoʻololi i ka ʻike nickel pipiʻi, e ʻoi aku ka maikaʻi o ka SDSS10.
I kēia mau lā, ua hoʻololi ʻia ʻo SDSS i nā ʻano wela like ʻole (cryogenic, anuanu a wela) e hoʻokō ai i nā waiwai mechanical maikaʻi loa6,7,8. Eia nō naʻe, ʻo ke kūpaʻa corrosion maikaʻi loa o SDSS ma muli o ka loaʻa ʻana o kahi kiʻi ʻoniʻoni ʻoniʻoni ʻoniʻoni ma luna o ka ʻili e hoʻopili ʻia e nā kumu he nui e like me ka heterogeneity inherent ma muli o ka hele ʻana o nā pae heterogeneous me nā palena palaoa ʻokoʻa, nā precipitates makemake ʻole a me nā pane like ʻole. deformations o austenitic a me ka ferritic pae7. No laila, ʻo ke aʻo ʻana i nā waiwai domain microscopic o ia mau kiʻiʻoniʻoni a hiki i ke kiʻekiʻe o ka hale uila e lilo i mea koʻikoʻi no ka hoʻomaopopo ʻana i ka ʻino SDSS a koi i nā ʻenehana hoʻokolohua paʻakikī. I kēia manawa, ʻaʻole hiki ke ʻike i nā ʻokoʻa kemika o nā ʻāpana ili o nā ʻano like ʻole e like me Auger electron spectroscopy11 a me X-ray photoelectron spectroscopy12,13,14,15 a me X-ray photoemission microscopy (HAX-PEEM)16. nā mokuʻāina kemika o ka mea like ma nā wahi like ʻole o ke ākea nanoscale. Ua hoʻopili ʻia kekahi mau noiʻi hou i ka hoʻokahe ʻia ʻana o ka chromium i ʻike ʻia me ka hana ʻino ʻana o nā kila stainless austenitic17, nā kila martensitic18 a me SDSS19,20. Eia naʻe, ua kālele nui kēia mau haʻawina i ka hopena o ka Cr heterogeneity (e laʻa, Cr3+ oxidation state) ma ke kū ʻana o ka corrosion. Hiki ke ho'okumu 'ia ka heterogeneity lateral i loko o nā moku'āina ho'ohāhā o nā mea e nā pūhui like 'ole me nā mea ho'ohui like, e like me ka hao oxides. ʻO kēia mau pūhui, i hoʻoili i kahi liʻiliʻi liʻiliʻi ma muli o ka mālama ʻana i ka thermomechanical, ma kahi kokoke i kekahi, akā ʻokoʻa i ka haku mele ʻana a me ka oxidation state16,21. No laila, no ka ʻike ʻana i ka haki ʻana o nā kiʻiʻoniʻoni oxide a me ka lua ma hope, pono e hoʻomaopopo i ka heterogeneity o ka ʻili ma ka pae microscopic. Me kēia mau koi, ʻaʻole naʻe nā koho quantitative e like me ka heterogeneity lateral i ka oxidation, ʻoi aku ka nui o Fe ma ka nano- a me ka unahi atomic, a ʻaʻole i ʻike ʻia kona pilina me ke kūpaʻa corrosion. A hiki i kēia manawa, ua hoʻohālikelike ʻia ke kūlana 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 nā keʻena hoʻoheheʻe nanoscale synchrotron. Hoʻohui pū ʻia me ka X-ray absorption spectroscopy (XAS), hiki i ka X-PEEM ke ana i ka XAS me ka hoʻonā kikoʻī a me ka spectral kiʻekiʻe, e hāʻawi ana i ka ʻike kemika e pili ana i ka hoʻohui ʻana o nā mea a me ko lākou kūlana kemika me ka hoʻonā spatial a hiki i ka iwakāluakūmākolu nanometer unahi. . ʻO kēia nānā spectromicroscopic o ka hoʻomaka ʻana e hoʻomaʻamaʻa i ka nānā ʻana i nā kemika kūloko a hiki ke hōʻike i nā loli kemika i loko o ke ākea o ka papa hao i ʻike ʻole ʻia ma mua.
Hoʻonui kēia haʻawina i nā pono o ka PEEM i ka ʻike ʻana i nā ʻokoʻa kemika ma ka nanoscale a hōʻike i kahi ʻano loiloi ʻili o ka pae atomic-level no ka hoʻomaopopo ʻana i ka hana corrosion o Ce-2507. Hoʻohana ʻo ia i kahi ʻano chemometric K-means24 i hoʻopaʻa ʻia no ka palapala ʻana i ka homogeneity kemika honua (hetero) o nā mea i hoʻopili ʻia, nona nā mokuʻāina kemika i hōʻike ʻia ma kahi hōʻike helu. ʻOkoʻa i ka corrosion i hoʻomaka ʻia e ka luku ʻia ʻana o ke kiʻi ʻoniʻoni chromium oxide i ka hihia kuʻuna, ʻoi aku ka liʻiliʻi o ka passivation a me ke kūpaʻa haʻahaʻa haʻahaʻa i kēia manawa e pili ana i nā nanoislands waiwai Fe3 + kūloko kokoke i ka papa Fe / Cr oxide, ʻo ia paha nā waiwai pale. Hoʻopau ka oxide i ke kiʻiʻoniʻoni kikoʻī a hana i ka pala.
Ua loiloi mua ʻia ka hana corrosive o SDSS 2507 me ka hoʻohana ʻana i nā ana electrochemical. Ma ka fig. Hōʻike ka Kiʻi 1 i nā ʻāpana Nyquist a me Bode no nā laʻana i koho ʻia i loko o kahi wai wai ʻakika (pH = 1) o FeCl3 ma ka wela lumi. ʻO ka electrolyte i koho ʻia e hana ma ke ʻano he mea oxidizing ikaika, e hōʻike ana i ke ʻano o ke kiʻi passivation e wāwahi. ʻOiai ʻaʻole i loaʻa ka lua paʻa i ka lua o ka lumi, ua hāʻawi ka loiloi i ka ʻike i nā hanana hiki ʻole a me ka corrosion ma hope. Ua hoʻohana 'ia ke kaapuni like (Fig. 1d) e hoʻokomo i ka spectroscopy impedance electrochemical (EIS), a ua hōʻike ʻia nā hualoaʻa kūpono ma ka Papa 1. Hōʻike ʻia nā semicircles incomplete i nā mea hoʻonā i hoʻoponopono ʻia a hana wela, ʻoiai ʻike ʻia nā semicircles i hoʻopaʻa ʻia i loko o nā mea ʻōwili anuanu (Fig.1b). I ka EIS spectroscopy, hiki ke no'ono'o 'ia ka radius o ka semicircle e like me ke kū'ē polarization (Rp)25,26. Ma kahi o 135 kΩ cm–2 ka Rp o ke ala holo kaʻa i hoʻoponopono ʻia i ka hoʻonā ʻana ma ka Papa 1, akā naʻe, ʻoi aku ka haʻahaʻa o nā kumu waiwai o ke ala holo i hana ʻia me ka wela a me ke anuanu, 34.7 a me 2.1 kΩ cm–2. ʻO kēia hōʻemi nui o ka Rp e hōʻike ana i ka hopena maikaʻi o ka deformation plastic ma ka passivation a me ke kūpaʻa corrosion, e like me ka hōʻike ʻana ma nā hōʻike mua27,28,29,30.
a Nyquist, b, c Bode impedance and phase diagrams, a me d like equivalent circuit circuit, where RS is the electrolyte resistance, Rp is the polarization resistance, and QCPE is the oxide of the constant phase element i hoʻohana 'ia e hoʻohālike i ka capacitance non-ideal capacitance (n). Hana ʻia nā ana EIS ma ka hikina kaapuni hāmama.
Hōʻike ʻia nā mea mau i ka manawa like ma ka ʻāpana Bode, me kahi pāpū ma ke alapine kiʻekiʻe e hōʻike ana i ka pale electrolyte RS26. I ka emi ʻana o ke alapine, piʻi ka impedance a loaʻa kahi kihi ʻāpana maikaʻi ʻole, e hōʻike ana i ka mana capacitance. Ke piʻi aʻe nei ke kihi o ka pae, e paʻa ana i ka palena kiʻekiʻe ma luna o kahi ākea ākea ākea, a laila emi iho (Fig. 1c). Eia nō naʻe, ma nā hihia ʻekolu, ʻoi aku ka liʻiliʻi o kēia kiʻekiʻe ma mua o 90 °, e hōʻike ana i ka hana capacitive kūpono ʻole ma muli o ka hoʻopuehu capacitive. No laila, hoʻohana ʻia ka QCPE ʻano hana mau (CPE) e hōʻike i ka puʻunaue interfacial capacitance e puka mai ana mai ka ʻeleʻele o ka ʻili a i ʻole ka inhomogeneity, ʻoi aku ka nui ma ka unahi atomic, fractal geometry, electrode porosity, non-uniform potential, a me geometry me ke ʻano o nā electrodes31,32. CPE impedance:
kahi j ka helu noonoo a me ω ka alapine huina. ʻO QCPE kahi alapine kūʻokoʻa kūʻokoʻa e kūlike me ka wahi ākea kūpono o ka electrolyte. n he helu mana ʻole e wehewehe ana i ke kaʻe ʻana o ka capacitor mai ka capacitance kūpono, ʻo ia hoʻi ʻo ka kokoke n i 1, ʻoi aku ka pili o ka CPE i ka capacitive maʻemaʻe, ʻoiai inā kokoke ka n i ka ʻole, ʻike ʻia ke kūʻē. ʻO nā liʻiliʻi liʻiliʻi o n, kokoke i ka 1, hōʻike i ka ʻano capacitive kūpono ʻole o ka ʻili ma hope o nā hoʻokolohua polarization. ʻOi aku ka kiʻekiʻe o ka QCPE o SDSS i ʻōwili ʻia ma mua o kona mau hoa, ʻo ia hoʻi, ʻoi aku ka liʻiliʻi o ka maikaʻi o ka ʻili.
Kūlike me ka nui o nā waiwai pale corrosion o nā kila kila, ʻo ka maʻiʻo Cr kiʻekiʻe o SDSS ka hopena maʻamau i ke kūpaʻa ʻino maikaʻi loa o SDSS ma muli o ka loaʻa ʻana o kahi kiʻiʻoniʻoni pale oxide passivating ma ka ʻili17. ʻO ia mau kiʻiʻoniʻoni passivating ka mea maʻamau i ka Cr3+ oxides a/a i ʻole hydroxides, i hui pū ʻia me Fe2+, Fe3+ oxides a/a i ʻole (oxy)hydroxides33. I loko nō o ka like ili uniformity, passivating oxide papa, a me ka ike ole ili māwae e like me microscopic measurements6,7, okoa ka corrosion o ka wela-hana a me ke anu-owili SDSS, no laila, i ka hohonu haʻawina o ka microstructural ano pono no ke kila deformation.
Ua aʻo nui ʻia ka microstructure o ke kila kila kila me ka hoʻohana ʻana i nā kukui X-ʻenehana kiʻekiʻe a me ka synchrotron (Nā Kiʻi Hoʻohui 1, 2). Hāʻawi ʻia kahi ʻike kikoʻī ma ka ʻIke Hoʻohui. ʻOiai aia ka manaʻo like ʻole ma ke ʻano o ka māhele nui, ua ʻike ʻia nā ʻokoʻa o nā hakina māhele nui, i helu ʻia ma ka Papa Pākuʻi 1. Aia paha kēia mau ʻokoʻa ma muli o nā hakina māhele like ʻole ma ka ʻili a me ka leo, i hoʻopili ʻia e nā ʻokoʻa X-ray diffraction (XRD) ʻike hohonu. ) me nā kumu ikehu like ʻole o nā photons34. ʻO nā hakina austenite kiʻekiʻe i loko o nā ʻāpana ʻōwili anu i hoʻoholo ʻia e XRD mai kahi kumu hoʻokolohua e hōʻike ana i ka passivation ʻoi aku ka maikaʻi a laila ʻoi aku ka maikaʻi o ka pale ʻana i ka corrosion35, ʻoiai ʻoi aku ka pololei a me nā hopena helu helu e hōʻike i nā ʻano kūʻē i nā hakina māhele. Eia kekahi, pili pū ka pale ʻana o ke kila ma ke ʻano o ka hoʻomaʻemaʻe ʻana i ka palaoa, ka hōʻemi ʻana i ka nui o ka palaoa, ka hoʻonui ʻana i nā microdeformations a me ka dislocation density e kū nei i ka wā thermomechanical treatment36,37,38. Ua hōʻike ʻia nā ʻano hana wela i kahi ʻano ʻano nui, e hōʻike ana i ka nui o ka micron, ʻoiai ʻo nā apo laulima i ʻike ʻia i loko o nā kiʻi anu (Supplementary Fig. 3) e hōʻike ana i ka hoʻomaʻemaʻe nui ʻana i ka nanosize i ka hana mua. Pono kēia i ke kiʻiʻoniʻoni passive. ka hoʻokumu ʻana a me ka hoʻonui ʻana i ka pale ʻana i ka corrosion. Hoʻopili pinepine ʻia ka ʻano dislocation kiʻekiʻe me ka pale haʻahaʻa i ka lua, i ʻae maikaʻi me nā ana electrochemical.
Ua aʻo ʻia nā hoʻololi i ke kūlana kemika o nā microdomains o nā mea nui me ka hoʻohana ʻana i ka X-PEEM. ʻOiai ʻoi aku ka nui o nā mea hoʻohuihui, ua koho ʻia ʻo Cr, Fe, Ni a me Ce39 ma ʻaneʻi, ʻoiai ʻo Cr ka mea nui no ka hoʻokumu ʻana i ka kiʻiʻoniʻoni passive, ʻo Fe ka mea nui no ke kila, a hoʻonui ʻo Ni i ka passivation a kaulike i ka pae ferrite-austenitic. ʻO ke kūkulu ʻana a me ka hoʻololi ʻana ke kumu o Ce. Ma ka hoʻokani ʻana i ka ikehu synchrotron beam, ua hopu ʻo XAS i nā hiʻohiʻona nui o Cr (L2.3 lihi), Fe (L2.3 lihi), Ni (L2.3 lihi), a me Ce (M4.5 lihi) mai ka ʻili. -2507 SDSS. Hana ʻia ka ʻikepili kūpono ma o ka hoʻopili ʻana i ka ikehu me ka ʻikepili i paʻi ʻia (e like me XAS ma Fe L2, 3 ribs40,41).
Ma ka fig. Hōʻike ka Figure 2 i nā kiʻi X-PEEM o ka hana wela (Fig. 2a) a me ka ʻōwili anuanu (Fig. 2d) Ce-2507 SDSS a me nā ʻaoʻao XAS Cr a me Fe L2,3 ma nā kūlana i kaha ʻia. ʻIke ʻia ka ʻaoʻao L2,3 XAS i nā mokuʻāina 3d ʻole o nā electrons ma hope o ka photoexcitation ma ka 2p3/2 (L3 edge) a me 2p1/2 (L2 edge) spin-orbit split level. Loaʻa ka ʻike e pili ana i ke kūlana valence o Cr mai ka nānā ʻana i ka diffraction X-ray o ka lihi L2,3 ma Fig. 2b,d. Hoʻohālikelike loulou. 42, 43 hōʻike ʻia ʻehā mau piko A (578.3 eV), B (579.5 eV), C (580.4 eV), a me D (582.2 eV) i nānā ʻia ma kahi kokoke i ka ʻaoʻao L3, e hōʻike ana i nā ion Cr3+ octahedral, pili i ka Cr2O3. Ua like ka spectra hoʻokolohua me nā helu kumu, e like me ka mea i hōʻike ʻia ma nā panela b a me e, i loaʻa mai nā helu kīhāpai he nui ma ke kikowaena Cr L2.3 me ka hoʻohana ʻana i kahi kahua aniani o 2.0 eV44. Ua uhi ʻia nā ʻaoʻao ʻelua o ka SDSS i hana ʻia me ka wela a me ka ʻōwili anu me kahi ʻāpana like ʻole o Cr2O3.
he kiʻi wela o X-PEEM i hana ʻia me ka SDSS wela e pili ana i ka lihi b Cr L2.3 a me ka lihi c Fe L2.3, d kiʻi Thermal X-PEEM o ka SDSS i ʻōwili anuanu e pili ana i ka lihi e Cr L2.3 a me f Fe L2.3 o ka ʻaoʻao (e). Hoʻolālā ʻia ke kikoʻī XAS ma nā kūlana spatial like ʻole i kaha ʻia ma nā kiʻi wela (a, d) e nā laina kikoʻī ʻalani ma (b) a me (e) e hōʻike ana i ka spectra XAS i hoʻohālikelike ʻia o Cr3+ me ka waiwai kīhāpai 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 absorption X-ray (mai haʻahaʻa a kiʻekiʻe).
ʻAʻohe o ke kaiapuni kemika o kēia mau mea metala, ʻo ke kūlana kemika o ka hoʻohui ʻana o nā mea hoʻohuihui Ni a me Ce no nā laʻana ʻelua i mau. Kiʻi hou aku. Ma ka fig. 5-9 hōʻike i nā kiʻi X-PEEM a me nā kikoʻī XAS e pili ana no Ni a me Ce ma nā kūlana like ʻole ma ka ʻili o nā mea hoʻohālike i hana ʻia me ka wela a me ke anu. Hōʻike ʻo Ni XAS i ke kūlana hoʻokahe o Ni2+ ma luna o ka ʻili holoʻokoʻa i ana ʻia o nā mea hoʻohālike i hana ʻia me ka wela a me ka ʻōwili anu (Hoʻohui Kūkākūkā). He mea koʻikoʻi ia i ke ʻano o nā mea hana wela, ʻaʻole i ʻike ʻia ka hōʻailona XAS o Ce, ʻoiai ke nānā ʻia ka spectrum o Ce3 + o nā mea hoʻoheheʻe anuanu i hoʻokahi manawa. Ua hōʻike ʻia ka nānā ʻana i nā kiko Ce i loko o nā laʻana i ʻōwili ʻia i ka Ce ma ke ʻano o nā wai.
I loko o ka SDSS thermally deformed, ʻaʻohe hoʻololi hoʻololi kūloko i XAS i ʻike ʻia ma ka ʻaoʻao Fe L2.3 (Fig. 2c). Eia naʻe, e like me ka mea i hōʻike ʻia ma ka fig. 2f, hoʻololi ka Fe matrix microscopically i kona kūlana kemika ma ʻehiku mau wahi i koho ʻole ʻia ma ka SDSS i ʻōwili ʻia. Eia hou, i mea e loaa ai ka manao pololei o na hoololi ana i ka mokuaina o Fe ma na wahi i kohoia ma ka Fig. 2f, ua hanaia na noii ili kūloko (Fig. 3 and Supplementary Fig. 10) i kohoia ai na wahi poai liilii. Ua hoʻohālike ʻia ka XAS spectra o ka Fe L2,3 lihi o nā ʻōnaehana α-Fe2O3 a me Fe2+ octahedral oxides me ka hoʻohana ʻana i ka helu ʻana o ka māla aniani me ka hoʻohana ʻana i nā māla aniani o 1.0 (Fe2+) a me 1.0 (Fe3+)44. Hoʻomaopopo mākou he ʻokoʻa nā symmetries kūloko o α-Fe2O3 a me γ-Fe2O3, Fe3O4 i hui pū ʻia o Fe2+ & Fe3+,47, a me FeO45 ma ke ʻano he divalent Fe2+ oxide (3d6). Hoʻomaopopo mākou he ʻokoʻa nā symmetries kūloko ka α-Fe2O3 a me γ-Fe2O3, Fe3O4 i hui pū ʻia o Fe2+ & Fe3+,47, a me FeO45 ma ke ʻano he divalent Fe2+ oxide (3d6).E hoʻomaopopo he ʻokoʻa nā symmetries kūloko o ka α-Fe2O3 a me ka γ-Fe2O3, Fe3O4 hui pū ʻo Fe2+ a me Fe3+,47 a me FeO45 ma ke ʻano o ka formally divalent oxide Fe2+ (3d6).E hoʻomaopopo he ʻokoʻa nā symmetries kūloko o ka α-Fe2O3 a me ka γ-Fe2O345,46, Fe3O4 nā hui ʻana o Fe2+ a me Fe3+,47 a me FeO45 e hana ma ke ʻano he divalent Fe2+ oxide (3d6). ʻO nā ion Fe3+ a pau i loko o ka α-Fe2O3 he mau kūlana Oh wale nō, ʻoiai ʻo γ-Fe2O3 ka mea maʻamau i hōʻike ʻia ma Fe3+ t2g [Fe3+5/3V1/3] eg O4 spinel me nā hakahaka ma nā kūlana. No laila, loaʻa i nā ion Fe3+ ma γ-Fe2O3 nā kūlana Td a me Oh. E like me ka mea i ʻōlelo ʻia ma ka hana mua, ʻoiai he ʻokoʻa nā lākiō ikaika o nā mea ʻelua, ʻo ka lākiō ikaika eg / t2g ʻo ≈1, ʻoiai ma kēia hihia ʻo ka lākiō ikaika i ʻike ʻia eg / t2g ma kahi o 1. Hoʻoholo kēia i ka hiki ke loaʻa ʻo Fe3 + wale nō i kēia hihia. Ke noʻonoʻo nei i ka hihia o Fe3O4 me ka hui pū ʻana o Fe2 + a me Fe3 +, ʻike ʻia kahi hiʻohiʻona nāwaliwali (ikaika) mua ma ka ʻaoʻao L3 o Fe e hōʻike ana i kahi liʻiliʻi (ʻoi aku ka nui) i ka mokuʻāina 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 i ka Fe2+ a me ka γ-Fe2O3, α-Fe2O3 a me/a i ʻole Fe3O4 ma luna o nā ʻili anuanu o nā composites.
Hoʻonui ʻia nā kiʻi wela electron photoemission o ka (a, c) a me (b, d) XAS spectra ma ka ʻaoʻao Fe L2,3 ma nā kūlana spatial like ʻole i loko o nā wahi i koho ʻia 2 a me E ma Fig. 2d.
ʻO nāʻikepili hoʻokolohua i loaʻa (Fig. 4a a me Supplementary Fig. 11) ua hoʻolālāʻia a hoʻohālikelikeʻia me nā mea o nā pūhui maʻemaʻe 40, 41, 48. Ma keʻano nui,ʻekolu mauʻano likeʻole o ka Fe L-edge XAS spectra (XAS-1, XAS-2 a me XAS-3: Fig. 4a) i nānāʻia ma nā wahi likeʻole. ʻO kahi kikoʻī, ua ʻike ʻia kahi kikoʻī e like me 2-a (i hōʻike ʻia me XAS-1) ma ke kiʻi 3b ma luna o ka ʻāina holoʻokoʻa o ka hoihoi, a ukali ʻia e kahi spectrum 2-b (i kapa ʻia ʻo XAS-2), ʻoiai ua ʻike ʻia kahi kikoʻī e like me E-3 ma ka fig. 3d (i kapa ʻia ʻo XAS-3) i ʻike ʻia ma kekahi mau wahi kūloko. ʻO ka mea maʻamau, hoʻohana ʻia nā ʻāpana ʻehā no ka ʻike ʻana i nā mokuʻāina valence i loaʻa i loko o kahi hāpana hoʻokolohua: (1) L3 a me L2 hiʻohiʻona spectral, (2) kūlana ikehu o L3 a me L2 hiʻohiʻona, (3) L3-L2 ʻokoʻa ikehu, (4) L2 ikaika ratio /L3. Wahi a nā ʻike maka (Fig. 4a), aia nā ʻāpana Fe ʻekolu, ʻo ia hoʻi ʻo Fe0, Fe2+, a me Fe3+, aia ma ka ʻili o ka SDSS i aʻo ʻia. Ua hōʻike pū ʻia ka lākiō ikaika L2/L3 i ka loaʻa ʻana o nā ʻāpana ʻekolu.
ʻIke ʻia ʻekolu ʻikepili hoʻokolohua like ʻole (nā laina paʻa XAS-1, XAS-2 a me XAS-3 e pili ana me 2-a, 2-b a me E-3 ma Fig. 2 a me Fig. 3) i hoʻohālikelike ʻia me ka hoʻohālikelike XAS Comparison spectra, octahedrons Fe2+, Fe3+, crystal field values ​​​​of 1.0 eV– 1. (XAS-1, XAS-2, XAS-3) a me ka ʻikepili LCF i hoʻopaʻa ʻia (laina ʻeleʻele paʻa), a me ka hoʻohālikelike ʻana i nā kikoʻī XAS-3 me Fe3O4 (ka mokuʻāina hui ʻia o Fe) a me Fe2O3 (fe3+ maʻemaʻe).
Ua hoʻohana ʻia kahi hui laina laina (LCF) kūpono o nā kūlana ʻekolu 40,41,48 e helu i ke ʻano o ka hao hao. Ua hoʻokō ʻia ʻo LCF no ʻekolu Fe L-edge XAS spectra i koho ʻia e hōʻike ana i ka ʻokoʻa kiʻekiʻe loa, ʻo ia hoʻi XAS-1, XAS-2 a me XAS-3, e like me ka hōʻike ʻana ma ka Fig. 4b–d. No nā lako LCF, ua noʻonoʻo ʻia ʻo 10% Fe0 i nā hihia āpau ma muli o ka liʻiliʻi liʻiliʻi a mākou i ʻike ai i nā ʻikepili āpau a me ka ʻoiaʻiʻo ʻo ka metala ferrous ka mea nui o ke kila. ʻOiaʻiʻo, ʻoi aku 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 ma mua o 4 nm), hiki ke ʻike i ka hōʻailona mai ka hao hao (Fe0) ma lalo o ka papa passivation. ʻOiaʻiʻo, ʻoi aku 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 ma mua o 4 nm), hiki ke ʻike i ka hōʻailona mai ka hao 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 (> 4 nm liʻiliʻi), kahi e hiki ai ke ʻike i ka hōʻailona mai ka matrix hao (Fe0) ma lalo o ka papa passivation.ʻOiaʻiʻo, ʻike ʻo X-PEEM i ka Fe (~ 6 nm) 49 hohonu ma mua o ka mānoanoa i manaʻo ʻia o ka papa oxide (ma luna o 4 nm wale nō), hiki ke ʻike i nā hōʻailona mai ka hao hao (Fe0) ma lalo o ka papa passivation. Ua hana ʻia nā hui like ʻole o Fe2+ a me Fe3+ no ka loaʻa ʻana o ka hopena maikaʻi loa no ka ʻikepili hoʻokolohua i ʻike ʻia. Ma ka fig. Hōʻike ka Figure 4b i ka hui pū ʻana o Fe2 + a me Fe3 + i ke kikoʻī XAS-1, kahi e kokoke ana nā ʻāpana o Fe2 + a me Fe3 +, ma kahi o 45%, e hōʻike ana i kahi kūlana hoʻoheheʻe hui ʻia o Fe. ʻOiai no ka spectrum XAS-2, lilo ka pākēneka o Fe2 + a me Fe3 + i ~ 30% a me 60%, kēlā me kēia. ʻOi aku ka haʻahaʻa o ka Fe2+ ma mua o ka Fe3+. ʻO ka lākiō Fe2+ a Fe3 o 1:2 ʻo ia hoʻi, hiki ke hana ʻia ʻo Fe3O4 ma ka ratio like o nā ion Fe. Eia hou, no ka XAS-3 spectrum, ua hoʻololi nā pakeneka o Fe2 + a me Fe3 + i ~ 10% a me 80%, e hōʻike ana i ka hoʻololi kiʻekiʻe o Fe2 + i Fe3 +. E like me ka mea i ʻōlelo ʻia ma luna, hiki ke hele mai ka Fe3+ mai α-Fe2O3, γ-Fe2O3 a i ʻole Fe3O4. No ka hoʻomaopopoʻana i ke kumu kūpono loa o Fe3 +, ua hoʻolālāʻia ka XAS-3 spectra me nā kūlana Fe3 + likeʻole i ka Fig. 4e e hōʻike ana i ka like me nā kūlanaʻelua i ka wā e noʻonoʻoʻia ai ka Peak B. Eia naʻe, ʻo ka ikaika o ka poʻohiwi (A: mai Fe2+) a me ka lākiō ikaika B/A e hōʻike ana ua kokoke ka spectrum o XAS-3 akā ʻaʻole like me ka γ-Fe2O3. Ke hoʻohālikelikeʻia me ka nui o γ-Fe2O3,ʻo ka Fe 2p XAS ka ikaika o ka piko A SDSS he kiʻekiʻe iki (Fig. 4e), e hōʻike ana i kahi kiʻekiʻe o Fe2 +. ʻOiai ua like ka spectrum o XAS-3 me ka γ-Fe2O3, kahi i loaʻa ai ʻo Fe3+ ma nā kūlana Oh a me Td, ʻo ka hoʻomaopopo ʻana i nā mokuʻāina valence like ʻole a me ka hoʻohui ʻana wale nō ma ka ʻaoʻao L2,3 a i ʻole ka lākiō ikaika L2/L3. he kumuhana mau e kūkākūkā ai ma muli o ka paʻakikī o nā mea like ʻole i pili i ka spectrum hope41.
Ma waho aʻe o ka hoʻokae ʻana o nā mokuʻāina kemika o nā wahi hoihoi i koho ʻia ma luna, ua loiloi ʻia ka heterogeneity kemika honua o nā mea kī Cr a me Fe ma ka hoʻokaʻawale ʻana i nā kikoʻī XAS āpau i loaʻa ma ka ʻaoʻao hāpana me ka hoʻohana ʻana i ke ʻano clustering K-means. Ua hoʻonohonoho ʻia nā ʻaoʻao ʻaoʻao Cr L ma ke ʻano e hana ai i ʻelua mau pūʻulu maikaʻi loa i puʻunaue ʻia i loko o nā mea hoʻohālike i hana ʻia me ka wela a me ke anu i hōʻike ʻia ma Fig. 5. Akaka, aole i ikeia na hoololi hale kuloko, no ka mea, ua like loa na kikowaena elua o ka XAS Cr spectra. ʻO kēia mau hiʻohiʻona hiʻohiʻona o nā pūʻulu ʻelua ua ʻaneʻane like me nā mea e pili ana iā Cr2O342, ʻo ia hoʻi, ua māhele like ʻia nā papa Cr2O3 ma luna o ka SDSS.
he pūʻulu o nā ʻāpana K-means L-edge Cr, b like XAS centroids. Nā hualoaʻa o K-means X-PEEM hoʻohālikelike o ka SDSS i ʻōwili anuanu: c pūʻulu o nā ʻāpana kihi K-means o Cr L2,3 a me d nā kikowaena XAS pili.
No ka hōʻike ʻana i kahi palapala ʻaoʻao FeL ʻoi aku ka paʻakikī, hoʻohana ʻia nā pūʻulu ʻehā a me ʻelima a me ko lākou mau kikowaena pili (māhele spectral) no nā mea hoʻohālike i hana wela a me ka ʻōwili anu. No laila, hiki ke loaʻa ka pākēneka (%) o Fe2 + a me Fe3 + ma ka hoʻoponopono ʻana i ka LCF i hōʻike ʻia ma Fig.4. Ua hoʻohana ʻia ka pseudoelectrode potential Epseudo ma ke ʻano he hana o Fe0 e hōʻike i ka inhomogeneity microchemical o ka kiʻiʻoniʻoni ʻokiʻoki. Hoʻohālikelike ʻia ʻo Epseudo e ka lula hui ʻana,
kahi o \(\rm{E}_{\rm{Fe}/\rm{Fe}^{2 + (3 + )}}\) i like me \(\rm{Fe} + 2e^ – \to\rm { Fe}^{2 + (3 + )}\), oia ka 0.440 a me 0.036 V. ʻO nā wahi me kahi haʻahaʻa haʻahaʻa he ʻoi aku ka kiʻekiʻe o nā pūhui Fe3+. ʻO ka hāʻawi ʻia ʻana i loko o kahi hāpana thermally deformed he ʻano papa me ka hoʻololi kiʻekiʻe ma kahi o 0.119 V (Fig. 6a,b). ʻO kēia māhele kūpono e pili kokoke ana i ka topography ili (Fig. 6a). ʻAʻole i ʻike ʻia nā hoʻololi ʻē aʻe e pili ana i ke kūlana i loko o ka lamellar i lalo (Fig. 6b). ʻO ka mea'ē aʻe, no ka huiʻana o nā oxides likeʻole me nā mea likeʻole o Fe2 + a me Fe3 + i loko o ka SDSS i'ōwiliʻia, hiki keʻikeʻia kahiʻano likeʻole o ka pseudopotential (Fig. 6c, d). ʻO Fe3+ oxides a/a i ʻole (oxy)hydroxides ka mea nui o ka corrosion i ke kila a hiki ke paʻa i ka oxygen a me ka wai50. I kēia hihia, hiki ke ʻike ʻia ua puʻunaue ʻia nā mokupuni waiwai i ka Fe3+ ma ka ʻāina a hiki ke noʻonoʻo ʻia he mau wahi corrosion. I kēia hihia, hiki ke noʻonoʻo ʻia ka gradient ma ke kahua hiki, ma mua o ka waiwai piha o ka hiki, he hōʻailona no ka localization o nā ʻāpana corrosion ikaika51. Hiki i kēia māhele like ʻole o Fe2+ a me Fe3+ ma ka ʻili o ka SDSS i ʻōwili ʻia i ke anuanu ke hoʻololi i nā waiwai kemika kūloko a hāʻawi i kahi ʻāpana ʻoi aku ka maikaʻi o ka ʻili o ka oxide film cracking a me nā hopena corrosion, a laila e ʻae ai i ka matrix metala e hoʻomau mau ʻia, e hopena i ka inhomogeneity kūloko. a ho'ēmi i nāʻano pale o ka papa passivating.
ʻO nā pūʻulu K-mean o Fe L2,3 mau ʻāpana lihi a me nā kikowaena XAS e pili ana no ka a-c wela-hana X-PEEM a me d-f SDSS i ʻōwili ʻia. a, d K-means cluster plot i uhi ʻia ma ke kiʻi X-PEEM. Ua ʻōlelo ʻia nā mana pseudoelectrode i manaʻo ʻia (epseudo) me nā kiʻi K-means cluster. ʻO ka ʻōlinolino o kahi kiʻi X-PEEM e like me ke kala i ka Fig.
Kūlike like ʻo Cr akā ʻokoʻa ke kūlana kemika o Fe ke alakaʻi i nā kumu like ʻole o ka haki ʻana o ke kiʻiʻoniʻoni oxide a me nā ʻano corrosion i loko o ka Ce-2507 i ʻōwili wela a i ʻōwili ʻia. Ua ʻike maikaʻi ʻia kēia waiwai o ka Ce-2507 cold rolled. E pili ana i ka hoʻokumu ʻana o nā oxides a me nā hydroxides o Fe i loko o ka ea lewa, ua pani ʻia kēia mau hopena ma kēia hana ma ke ʻano he hopena kūʻokoʻa.
Ma muli o ke ana ʻana o X-PEEM, ua loaʻa ka hopena i luna ma kēia mau hihia. Hoʻopili ʻia kahi poʻohiwi liʻiliʻi e pili ana me Fe0 me ka hao metala lalo. ʻO ka hopena o ka Fe metala me ke kaiapuni e alakaʻi i ka hoʻokumu ʻana i kahi papa Fe(OH)2 (equation (5)), e hoʻonui ai i ka hōʻailona Fe2+ i ka XAS o ka ʻaoʻao L o Fe. ʻO ka loaʻa ʻana o ka ea lōʻihi ka hopena i ka hoʻokumu ʻana o Fe3O4 a me / a i ʻole Fe2O3 oxides ma hope o Fe(OH)252,53. ʻElua ʻano ʻano paʻa Fe, Fe3O4 a me Fe2O3, hiki ke hana ʻia i loko o kahi papa pale waiwai Cr3+, kahi e makemake ai ʻo Fe3O4 i kahi ʻano like ʻole a hui pū. ʻO ka loaʻa ʻana o nā hopena ʻelua i nā mokuʻāina oxidation hui ʻia (XAS-1 spectrum). ʻO ke kikoʻī XAS-2 e pili ana me Fe3O4. ʻOiai ua ʻike ʻia ka spectra XAS-3 ma kekahi mau kūlana i ka hoʻololi piha ʻana i γ-Fe2O3. No ka mea he 50 nm ka hohonu o nā hihi X i wehe ʻole ʻia, ʻo ka hōʻailona mai ka papa lalo e hopena i ka ikaika o ka piko A.
Hōʻike ka spectrum XRD i ka ʻāpana Fe i loko o ke kiʻiʻoniʻoni oxide i kahi ʻano papa, i hui pū ʻia me ka papa Cr oxide. ʻOkoʻa i ke ʻano passivation o ka corrosion ma muli o ka inhomogeneity kūloko o Cr2O317, ʻoiai ke ʻano o ka papa ʻaʻahu o Cr2O3 i loko o kēia haʻawina, ua ʻike ʻia ke kūpaʻa haʻahaʻa haʻahaʻa i kēia hihia, ʻoi aku hoʻi no nā laʻana i ʻōwili ʻia. Hiki ke hoʻomaopopo ʻia ke ʻano i ʻike ʻia ma ke ʻano he heterogeneity o ke kūlana oxidation kemika o ka papa luna (Fe) e pili ana i ka hana ʻino. ʻO ka hoʻololi lohi o nā ion metala a i ʻole oxygen i loko o ka lattice ma muli o ka stoichiometry like o ka luna (Fe oxide) a me nā papa haʻahaʻa (Cr oxide)52,53 alakaʻi i ka pilina maikaʻi (adhesion) ma waena o lākou. ʻO kēia hoʻi, hoʻomaikaʻi i ka pale ʻana i ka corrosion. No laila, ʻoi aku ka maikaʻi o ka stoichiometry hoʻomau, ʻo ia hoʻi, hoʻokahi kūlana hoʻokahe o Fe, ma mua o nā hoʻololi stoichiometric hikiwawe. ʻO ka SDSS i hoʻoheheʻe ʻia i ka thermally he ʻano like ʻole o ka ʻili a me kahi papa pale denser, kahi e hāʻawi ai i ka pale corrosion ʻoi aku ka maikaʻi. Eia nō naʻe, no ka SDSS i ʻōwili ʻia i ke anuanu, ʻo ka noho ʻana o nā mokupuni Fe3 +-waiwai ma lalo o ka pale pale e hoʻopau i ka pono o ka ʻili a hoʻoulu i ka galvanic corrosion o ka substrate kokoke, e alakaʻi ana i ka emi ʻana o Rp (Table 1) i ka spectra EIS a me kāna corrosion. kūʻē. No laila, ʻo nā mokupuni i hāʻawi ʻia ma ka ʻāina i waiwai nui i ka Fe3+ ma muli o ka hoʻololi ʻana i ka plastic ka mea nui i ka hana kūʻē ʻana i ka corrosion, ʻo ia ka hopena o kēia hana. No laila, hōʻike kēia haʻawina i nā spectromicrographs o ka hōʻemi ʻana i ke kūpaʻa corrosion ma muli o ka deformation plastic o nā laʻana SDSS i aʻo ʻia.
Eia kekahi, ʻoiai ʻoi aku ka maikaʻi o ka hoʻohui ʻana i ka honua ma nā ʻāpana ʻelua, ʻoi aku ka paʻakikī o ka launa ʻana o kēia mea i hoʻohui ʻia me ka matrix kila hoʻokahi e pili ana i ka hana corrosion ma muli o ka nānā ʻana i nā microscopy spectroscopic. Hōʻike ʻia ka hōʻailona Ce (ma ka XAS M-edge) 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 ʻana o Ce i loko o ka matrix kila ma kahi o ka hoʻohuihui homogeneous. ʻOiai ʻaʻole i hoʻomaikaʻi ʻia nā waiwai mechanical o SDSS6,7, ʻo ka hiki ʻana o REE e hōʻemi i ka nui o nā inclusions a manaʻo ʻia e kāohi i ka pitting ma ke kumu54.
I ka hopena, hōʻike kēia hana i ka hopena o ka heterogeneity ili ma ka corrosion o 2507 SDSS i hoʻololi ʻia me ka cerium ma ka helu ʻana i ka ʻike kemika o nā mea nanoscale. Ua pane mākou i ka nīnau no ke aha e ʻino ai ke kila kila ʻoiai ke uhi ʻia me kahi ʻāpana ʻokikene pale ma ke aʻo nui ʻana i ka microstructure, ke ʻano kemika o nā hiʻohiʻona o ka ʻili a me ka hana hōʻailona me ka hoʻohana ʻana i ka hui K-means. Ua hoʻokumu ʻia ʻo Fe3+-waiwai mokupuni, me kā lākou octahedral a me ka tetrahedral coordination a puni ka hale o Fe2+/Fe3+ i hui ʻia, he kumu ia o ka luku kiʻi ʻoniʻoni a me kahi kumu o ka corrosion o ka SDSS i ʻōwili ʻia. ʻO nā Nanoislands i hoʻomalu ʻia e Fe3+ ke alakaʻi i ke kūpaʻa ʻino maikaʻi ʻole ma ke alo o kahi papa pasivating stoichiometric Cr2O3. Ma waho aʻe o nā holomua metodological i hana ʻia i ka hoʻoholo ʻana i ka hopena o ka heterogeneity chemical nanoscale i ka corrosion, manaʻo ʻia ka hana o kēia manawa e hoʻoulu i nā kaʻina hana ʻenehana e hoʻomaikaʻi i ke kūpaʻa ʻana o nā kila kila i ka wā o ka hana kila.
No ka hoʻomākaukau ʻana i ka Ce-2507 SDSS ingots i hoʻohana ʻia i kēia haʻawina, ua hoʻoheheʻe ʻia nā mea i hui ʻia, me ka Fe-Ce master alloy i hoʻopaʻa ʻia me nā paipu hao maʻemaʻe, i hoʻoheheʻe ʻia i loko o ka umu hoʻoheheʻe 150 kg e hana i ke kila hoʻoheheʻe ʻia a ninini ʻia i loko o ka hoʻoheheʻe ʻana. Hoʻopaʻa ʻia nā mea hoʻohui kemika i ana ʻia (wt%) ma ka Papa Pākuʻi 2. Ua wela mua ka ingot i mau poloka. A laila ua hoʻopiliʻia ke kila ma 1050 ° C no nā minuke 60 i kahi hopena paʻa, a laila hoʻopauʻia i ka wai i ka mahana wela. Ua aʻo ʻia nā laʻana i aʻo ʻia me ka hoʻohana ʻana i ka TEM a me DOE e aʻo i nā pae, ka nui o ka palaoa a me ka morphology. Hiki ke loaʻa ka ʻike kikoʻī hou aku e pili ana i nā laʻana a me ke kaʻina hana ma nā kumu ʻē aʻe6,7.
Kaʻina hana cylindrical samples (φ10 mm × 15 mm) no ke kaomi wela me ke koʻi o ka cylinder e like me ke kuhikuhi deformation o ka poloka. Ua hanaʻia ka hoʻoemi kiʻekiʻe ma keʻano maʻamau i ka 0.01-10 s-1 ma nāʻano mahana likeʻole ma kahi o 1000-1150 ° C me ka hoʻohanaʻana i ka Gleeble-3800 thermal simulator. Ma mua o ka hoʻololi ʻana, ua hoʻomehana ʻia nā laʻana i ka mahana i koho ʻia ma kahi o 10 °C s-1 no 2 min e hoʻopau i ka gradient mahana. Ma hope o ka loaʻa ʻana o ka like ʻana o ka mahana, ua hoʻololi ʻia nā mea hoʻohālike i ka waiwai kānana maoli o 0.7. Ma hope o ka deformation, hoʻopau koke ʻia me ka wai e mālama i ke ʻano deformed. A laila ua ʻoki ʻia nā ʻano mea paʻakikī e like me ke ʻano o ka hoʻoomi ʻana. No kēia noiʻi ponoʻī, ua koho mākou i kahi hōʻailona thermally deformed ma 1050°C, 10 s-1 ma muli o kahi microhardness i ʻike ʻia ma mua o nā specimens7.
ʻO ka nui (80 × 10 × 17 mm3) nā laʻana o ka Ce-2507 solid solution i hoʻāʻo ʻia ma kahi ʻekolu-phase asynchronous two-roll deformation machine LG-300, i hāʻawi i nā waiwai mechanical maikaʻi loa ma waena o nā papa deformation ʻē aʻe a pau6. He 0.2 m·s-1 ka mānoanoa a me ka emi ʻana o ka mānoanoa no kēlā me kēia ala.
Ua hoʻohana ʻia kahi kahua hana electrochemical Autolab PGSTAT128N no ke ana ʻana i ka SDSS ma hope o ka ʻōwili ʻana i ke anuanu a hiki i 90% ka hoʻemi ʻana o ka mānoanoa (1.0 e like me ke kānana ʻoiaʻiʻo) a me ke kaomi wela i ka 0.7 kānana maoli ma 1050 oC a me 10 s-1. ʻO ka hale hana he ʻekolu-electrode cell me ka calomel electrode saturated e like me ka electrode reference, kahi graphite counter electrode, a me kahi laʻana SDSS e like me ka electrode hana. Ua ʻoki ʻia nā mea hoʻohālike i loko o nā cylinders me ke anawaena o 11.3 mm, i nā ʻaoʻao i hoʻopaʻa ʻia nā uea keleawe. A laila ua ninini ʻia ka laʻana me ka resin epoxy, e waiho ana i kahi wahi ākea o 1 cm2 ma ke ʻano he electrode hana (ka ʻili haʻahaʻa o ka cylindrical sample). E mālama pono i ka wā o ka ho'ōla ʻana i ka epoxy a i ka wā e hoʻomaʻamaʻa ai a hoʻoliʻi ʻia e pale aku i ka haki ʻana. Hoʻopili ʻia ka ʻili hana a hoʻomaʻamaʻa ʻia me ka hoʻokuʻu ʻia ʻana o ke daimana me ka nui o 1 micron, hoʻomaʻemaʻe ʻia me ka wai distilled a me ka ethanol a maloʻo i ka ea anuanu. Ma mua o nā ana electrochemical, ua hōʻike ʻia nā laʻana i poni ʻia i ka ea no kekahi mau lā e hana i kahi kiʻiʻoniʻoni oxide kūlohelohe. Ua hoʻohana ʻia kahi ʻano wai wai o FeCl3 (6.0 wt.%), i hoʻopaʻa ʻia me HCl i ka pH = 1.0 ± 0.01, e hoʻolalelale i ka ʻino ʻana o ke kila kila55, no ka mea, loaʻa ia ma nā wahi ʻino kahi i loaʻa ai nā ion chloride me ka mana oxidizing ikaika a me ka pH haʻahaʻa e like me ka ASTM. ʻO nā kūlana i manaʻo ʻia ʻo G48 a me A923. Hoʻokomo ʻia nā laʻana i loko o ka hopena hoʻāʻo no 1 hola ma mua o ke ana ʻana i mea e hiki ai i kahi mokuʻāina kokoke i kahi paʻa. No ka hoʻonā paʻa, hana wela a ʻōwili anu, ʻo 1 × 105 ~ 0.1 Hz ka nui o ke ana ʻana impedance, a ʻo 5 mV ka hiki o ke kaapuni hāmama, ʻo ia ka 0.39, 0.33, a me 0.25 VSCE. Ua hana hou ʻia kēlā me kēia hoʻāʻo electrochemical o kekahi laʻana ma lalo o ʻekolu mau manawa ma lalo o nā kūlana like e hōʻoia i ka reproducibility ʻikepili.
No nā ana HE-SXRD, ua ana ʻia nā poloka kila duplex rectangular 1 × 1 × 1.5 mm3 ma kahi laina Wiggler Brockhouse ikaika nui ma CLS, Kanada e helu i ka haku mele56. Ua lawe ʻia ka hōʻiliʻili ʻikepili ma ka lumi wela ma Debye-Scherrer geometry a i ʻole transport geometry. ʻO ka lōʻihi o ka nalu o nā kukui X i hoʻopaʻa ʻia i ka LaB6 calibrant ʻo 0.212561 Å, e pili ana me 58 keV, ʻoi aku ka kiʻekiʻe ma mua o ka Cu Kα (8 keV) i hoʻohana mau ʻia ma ke ʻano he kumu kukui X-ray. Hoʻokomo ʻia ka hāpana ma kahi mamao o 740 mm mai ka mea ʻike. He 0.2 × 0.3 × 1.5 mm3 ka nui ʻike o kēlā me kēia laʻana, i hoʻoholo ʻia e ka nui o ka beam a me ka mānoanoa hāpana. Ua hōʻiliʻili ʻia kēlā me kēia ʻikepili me ka hoʻohana ʻana i kahi mea ʻike wahi Perkin Elmer, ʻike maka X-ray panel, 200 µm pixels, 40 × 40 cm2, me ka hoʻohana ʻana i ka manawa hoʻolaha o 0.3 kekona a me 120 mau kiʻi.
Ua hoʻokō ʻia nā ana X-PEEM o ʻelua ʻōnaehana hoʻohālike i koho ʻia ma ke kahua hoʻopau PEEM o ka laina Beamline MAXPEEM ma ke keʻena ʻo MAX IV (Lund, Suedena). 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 hoʻoheheʻe ʻia i loko o kahi keʻena maloʻo ultrahigh ma mua o ka hoʻomālamalama ʻia me nā photon synchrotron. Loaʻa ka hoʻonā ikehu o ka lāʻau ma ke ana ʻana i ka spectrum puka ion mai N 1 s a i 1\(\pi _g^ \ast\) o ka ʻāpana hoʻoulu me hv = 401 eV ma N2 a me ka hilinaʻi o ka ikehu photon ma E3/2.57. Hāʻawi ka Spectral fit i ka ΔE (ka laula laina spectral) ~0.3 eV ma luna o ke ana ikehu. No laila, ua manaʻo ʻia ka hoʻonā ʻana o ka ikehu beamline ʻo E/∆E = 700 eV/0.3 eV > 2000 a me ka flux ≈1012 ph/s ma o ka hoʻohana ʻana i kahi monochromator SX-700 i hoʻololi ʻia me kahi pahu Si 1200-laina mm−1 no ka Fe 2p L2,3 edge. L2,3 lihi, a me Ce M4,5 lihi. No laila, ua manaʻo ʻia ka hoʻonā ʻana o ka ikehu beamline ʻo E/∆E = 700 eV/0.3 eV > 2000 a me ka flux ≈1012 ph/s ma o ka hoʻohana ʻana i kahi monochromator SX-700 i hoʻololi ʻia me kahi pahu Si 1200-line mm−1 no ka Fe 2p L2.2 edge, Nip232 edge L2.3 lihi, a me Ce M4.5 lihi. 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 beam 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 ʻāpana Si o nā laina 1200 / mm no Fe lihi 2p L2 ,32, Cr lihi 2p L2,32, Cr L2 lihi. a me Ce lihi 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 1200 laina Si grating. 3, Cr lihi 2p L2.3, Ni lihi 2p L2.3 a me Ce lihi M4.5.E hoʻonui i ka ikehu photon ma nā ʻanuʻu 0.2 eV. I kēlā me kēia ikehu, ua hoʻopaʻa ʻia nā kiʻi PEEM me ka TVIPS F-216 CMOS detector me kahi 2 x 2 binning fiber optic pili e hāʻawi ana i 1024 × 1024 pixels ma kahi kahua ʻike 20 µm. ʻO ka manawa hoʻolaha o nā kiʻi he 0.2 kekona, he 16 mau kiʻi ma waena. Koho ʻia ka ikehu kiʻi photoelectron ma ke ʻano e hāʻawi ai i ka hōʻailona electron lua kiʻekiʻe. Hana ʻia nā ana a pau ma ke ʻano maʻamau o kahi kukuna photon polarly polarized. No ka 'ike hou aku e pili ana i ke ana, e nana i ka ha'awina mua58. Ma hope o ke aʻo ʻana i ka huina electron yield (TEY)59 mode detection a me kāna noi ʻana ma X-PEEM, ua manaʻo ʻia ka hohonu ʻike o kēia ʻano ma ~ 4-5 nm no ka hōʻailona Cr a me ~ 6 nm no ka hōʻailona Fe. ʻO ka hohonu Cr kahi kokoke loa i ka mānoanoa kiʻiʻoniʻoni oxide (~ 4 nm) 60,61 ʻoiai ʻo ka hohonu Fe ʻoi aku ka nui ma mua o ka mānoanoa film oxide. ʻO ka XAS i hōʻiliʻili ʻia ma kahi kokoke i ka ʻaoʻao Fe L he hui ʻia o ka hao ʻokikene XAS a me FeO mai ka matrix. I ka hihia mua, ʻo ka ikaika o nā electrons i hoʻokuʻu ʻia ma muli o nā ʻano electrons hiki ke hāʻawi iā TEY. Eia nō naʻe, ʻo kahi hōʻailona hao maʻemaʻe e koi i ka ikehu kinetic kiʻekiʻe no nā electrons e hele i ka papa oxide, hiki i ka ʻili, a e hōʻiliʻili ʻia e ka mea hoʻoponopono. I kēia hihia, ʻo ka hōʻailona Fe0 ka mea nui ma muli o nā electrons LVV Auger a me nā electrons lua i hoʻokuʻu ʻia e lākou. Eia kekahi, ʻo ka ikaika TEY i hāʻawi ʻia e kēia mau electrons decays i ka wā o ka electron escape path49 e hōʻemi hou ana i ka hōʻailona spectral o Fe0 i ka palapala hao XAS.
ʻO ka hoʻohui ʻana i ka ʻimi ʻikepili i loko o nā cubes data (X-PEEM data) kahi hana nui i ka unuhi ʻana i ka ʻike pili (kemika a i ʻole nā ​​waiwai kino) ma ke ʻano multidimensional. Hoʻohana nui ʻia ka K-means clustering ma kekahi mau wahi, e like me ka ʻike mīkini, ka hoʻoili kiʻi, ka ʻike ʻana i nā kumu i mālama ʻole ʻia, ka naʻauao hana, a me ka loiloi classificatory24. No ka laʻana, hoʻohana maikaʻi ʻia ka hui ʻana o K-means i ka hui ʻana i ka ʻikepili kiʻi hyperspectral62. Ma ke kumu, no ka ʻikepili lehulehu, hiki i ka K-means algorithm ke hui maʻalahi iā lākou e like me ka ʻike e pili ana i ko lākou mau ʻano (photon energy features). ʻO K-means clustering he algorithm iterative no ka hoʻokaʻawale ʻana i nā ʻikepili i loko o nā pūʻulu K non-overlapping (clusters), kahi o kēlā me kēia pika i kahi puʻupuʻu kikoʻī ma muli o ka puʻunaue spatial o ka inhomogeneity kemika i loko o ke kila microstructural haku mele. He ʻelua ʻanuʻu ka K-means algorithm: ʻo ka ʻanuʻu mua e helu i nā K centroids, a ʻo ka ʻanuʻu ʻelua e hāʻawi i kēlā me kēia kiko i kahi hui me nā centroids kokoke. Ua wehewehe ʻia ke kikowaena o ka ʻumekaumaha o kahi pūʻulu ma ke ʻano he helu helu o nā helu ʻikepili (XAS spectra) o ia pūʻulu. Aia nā mamao like ʻole e wehewehe i nā kikowaena pili e like me nā mamao Euclidean. No ke kiʻi hoʻokomo o px,y (x a me y ka hoʻonā i nā pika), ʻo CK ke kikowaena o ka umekaumaha o ka hui; Hiki ke hoʻokaʻawale ʻia kēia kiʻi i nā pūʻulu K me ka hoʻohana ʻana iā K-means63. ʻO nā pae hope loa o ka K-means clustering algorithm:
KaʻAnuʻu 2. E helu i ka degere o ka lālā o nā pika a pau e like me ka centroid o kēia manawa. No ka laʻana, ua helu ʻia mai ka mamao Euclidean d ma waena o ke kikowaena a me kēlā me kēia pika:
'anuʻu 3 E hāʻawi i kēlā me kēia pika i ka centroid kokoke loa. A laila e helu hou i nā kūlana K centroid penei:
KaʻAnuʻu 4. E hana hou i ke kaʻina hana (nā hoohalike (7) a me (8)) a hiki i ka hui ana o na kikowaena. Hoʻopili nui ʻia nā hopena maikaʻi o ka puʻupuʻu me ke koho maikaʻi loa o nā centroids mua63. No ka PEEM hoʻolālā ʻikepili o nā kiʻi kila, maʻamau X (x × y × λ) he cube o 3D array data, ʻoiai nā x a me y e hōʻike ana i ka ʻike kikoʻī (pixel resolution) a ʻo ke axis λ e pili ana i ke ʻano spectral ikehu o nā kiʻi. Ua hoʻohana ʻia ka algorithm K-means no ka ʻimi ʻana i nā wahi hoihoi i ka ʻikepili X-PEEM ma ka hoʻokaʻawale ʻana i nā pika (clusters a i ʻole sub-blocks) e like me ko lākou mau hiʻohiʻona spectral a me ka unuhi ʻana i ka centroid maikaʻi loa (XAS spectral curve) no kēlā me kēia analyte (cluster). Hoʻohana ʻia ia e aʻo i ka hāʻawi ʻana i ka spatial, nā loli spectral kūloko, ka hana 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 X-PEEM i hana ʻia me ka wela a me ke anuanu. Ua ho'āʻo ʻia nā helu like ʻole o K-clusters (microstructural regions) no ka ʻike ʻana i nā pūʻulu a me nā centroids maikaʻi loa. Ke hōʻike ʻia ka pakuhi, hāʻawi hou ʻia nā pika i nā centroid cluster kūpono. ʻO kēlā me kēia māhele waihoʻoluʻu e pili ana i ke kikowaena o ka hui, e hōʻike ana i ka hoʻonohonoho spatial o nā mea kemika a kino paha. ʻO nā centroids i unuhi ʻia he hui laina o ka spectra maʻemaʻe.
Loaʻa nā ʻikepili e kākoʻo ana i nā hopena o kēia noiʻi mai ka mea kākau WC ma muli o ke noi kūpono.
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