Ke hōʻike nei i ka mana o ka Nanoscale Chemical Inhomogeneity ma ka Corrosion o Cerium-Modified 2507 Super Duplex Stainless Steel

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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 maʻamau ka ʻinoʻino a me ka ʻino ʻana o ke kila me ka luku ʻana i kēia mau papa, akā kakaikahi ma ka pae microscopic, ma muli o ke kumu o ka inhomogeneity o ka ʻili.Ma kēia hana, ʻike ʻia ka heterogeneity kemika o ka nanoscale e ka spectroscopic microscopy a me ka nānā ʻana chemometric i ka decomposition a me ka corrosion o ka cerium i hoʻololi ʻia ʻo super duplex stainless steel 2507 (SDSS) i ka wā o kāna hana deformation wela.ʻaoʻao ʻē aʻe.ʻOiai ua hōʻike ʻo X-ray photoelectron microscopy i ka uhi ʻokoʻa o ka papa Cr2O3 maoli, ua hōʻike ʻo SDSS i ʻōwili ʻia i nā hopena passivation maikaʻi ʻole ma muli o ka puʻunaue kūloko o Fe3+ waiwai nanoislands ma ka papa Fe/Cr oxide.Hāʻawi kēia ʻike ma ka pae atomika i ka ʻike hohonu o ka ʻino kila kuhiliʻole a manaʻo ʻia e kōkua i ke kaua ʻana i ka ʻino o nā metala kiʻekiʻe like.
Mai ka hana ʻana o ke kila kila, ua hoʻohālikelike ʻia ke kūpaʻa ʻana o ka ferrochromium alloys i ka chromium, ka mea i hana i kahi oxide/oxyhydroxide ikaika e hōʻike ana i nā ʻano pasivating i ka hapa nui o nā kaiapuni.Hoʻohālikelike ʻia me nā kila kuhili ʻole maʻamau (austenitic a me ferritic), super duplex stainless steels (SDSS) me ka ʻoi aku ka maikaʻi o ka corrosion ʻoi aku ka maikaʻi o nā waiwai mechanical1,2,3.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 i ka lōʻihi o ka lawelawe ʻana a me nā noi ākea i ka hoʻomalu ʻana i ka haumia, nā ipu kemika, a me ka ʻoihana ʻaila a me ke kinoea waho4.Eia nō naʻe, ʻo ke ʻano haiki o nā mahana lapaʻau wela a me ka maikaʻi ʻole o ke ʻano hana keakeʻa i kāna hoʻohana ākea.No laila, ua hoʻololi ʻia ka SDSS e hoʻomaikaʻi i nā waiwai i luna.No ka laʻana, ua hoʻokomo ʻia ka hoʻololi Ce a me nā hoʻohui kiʻekiʻe o N 6, 7, 8 ma 2507 SDSS (Ce-2507).He hopena maikaʻi ka manaʻo kūpono o 0.08 wt.% rare earth element (Ce) i nā waiwai mechanical o ka DSS, no ka mea, hoʻomaikaʻi ia i ka hoʻomaʻemaʻe palaoa a me ka ikaika palena o ka palaoa.Ua hoʻomaikaʻi hou ʻia ka ʻaʻahu a me ke kūpaʻa ʻana, 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 (haʻahaʻa haʻahaʻa, anu 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 oxide ma luna o ka ʻili, i hoʻopili ʻia e nā kumu he nui, e like me ka hele ʻana o nā pae he nui me nā palena palaoa like ʻole, nā precipitates makemake ʻole a me nā hopena like ʻole.ʻo ka microstructure inhomogeneous o loko o nā ʻano austenitic a me nā ʻano ferritic he deformed 7 .No laila, ʻo ke aʻo ʻana i nā waiwai microdomain o ia mau kiʻiʻoniʻoni ma ke kiʻekiʻe o ka hoʻolālā uila he mea koʻikoʻi loa ia no ka hoʻomaopopo ʻana i ka ʻino SDSS a koi i nā ʻenehana hoʻokolohua paʻakikī.A hiki i kēia manawa, ʻike ʻia nā ʻano hana e like me Auger electron spectroscopy11 a me X-ray photoelectron spectroscopy12,13,14,15 a me ka ʻōnaehana photoelectron photoelectron paʻakikī e hoʻokaʻawale, akā pinepine ʻole e hoʻokaʻawale, nā mokuʻāina kemika o ka mea like ma nā wahi like ʻole ma ke ākea ma ka nanoscale.Ua hoʻopili kekahi mau haʻawina hou i ka hoʻokahe ʻana o ka chromium kūloko i ka ʻano ʻino i ʻike ʻia o 17 austenitic stainless steels, 18 martensitic stainless steels, a me SDSS 19, 20. Eia naʻe, ua nānā nui kēia mau haʻawina i ka hopena o ka Cr heterogeneity (eg, Cr3+ oxidation state) ma ka pale ʻana i 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.Loaʻa kēia mau pūhui i kahi liʻiliʻi liʻiliʻi i hana ʻia ma ka thermomechanically e pili kokoke ana kekahi i kekahi, akā ʻokoʻa i ka haku mele ʻana a me ke kūlana oxidation16,21.No laila, ʻo ka hōʻike ʻana i ka luku ʻia ʻana o nā kiʻiʻoniʻoni oxide a laila pitting e pono ai ka hoʻomaopopo ʻana i ka inhomogeneity o ka ʻili ma ka pae microscopic.ʻOiai ʻo kēia mau koi, ʻaʻole naʻe nā loiloi quantitative e like me ka heterogeneity oxidation lateral, ʻoi aku ka hao ma ka pālākiō nano/atomic, a ʻaʻole i ʻike ʻia ko lākou koʻikoʻi no ka pale ʻana i ka corrosion.A hiki i kēia manawa, ua wehewehe nui ʻia ke kūlana kemika o nā mea like ʻole, e like me Fe a me Ca, ma nā laʻana kila me ka hoʻohana ʻana i ka microscopy photoelectron X-ray palupalu (X-PEEM) i loko o nā keʻena radiation synchrotron nanoscale.Hoʻohui pū ʻia me nā ʻenehana X-ray absorption spectroscopy (XAS), hiki i ka X-PEEM ke ana i ka XAS me ka hoʻonā kiʻekiʻe spatial a spectral, e hāʻawi ana i ka ʻike kemika e pili ana i ka haku mele a me kona kūlana kemika me ka hoʻonā spatial a hiki i ka pālākiō nanometer 23.ʻO kēia ʻike kikoʻī o ke kahua o ka hoʻomaka ʻana ma lalo o kahi microscope e hoʻomaʻamaʻa i nā hoʻokolohua kemika kūloko a hiki ke hōʻike kikoʻī i nā loli kemika i ʻike ʻole ʻia ma ka papa Fe.
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 ia i ka K-means cluster chemometric data24 no ka palapala ʻana i ka haku mele honua (heterogeneity) o nā mea e pili ana, me ko lākou mau mokuʻāina kemika i hōʻike ʻia ma kahi hōʻike helu.ʻAʻole e like me ka corrosion maʻamau i hana ʻia e ka chromium oxide film breakdown, ʻo ka passivation maikaʻi ʻole o kēia manawa a me ka pale ʻana i ka corrosion maikaʻi ʻole e pili ana i nā nanoislands waiwai Fe3+ ma kahi kokoke i ka papa Fe/Cr oxide, a he mea ia e hoʻouka ʻia e ka oxide pale.Hoʻokumu ia i kahi kiʻiʻoniʻoni ma kahi a hoʻoulu i ka corrosion.
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 ka waiʻawaʻawa (pH = 1) wai o FeCl3 ma ka lumi wela.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 wela o ka lumi, ua hāʻawi kēia mau loiloi i ka ʻike i nā hanana hiki ʻole a me nā kaʻina hana post-corrosion.Ua ho'ohana 'ia ke kaapuni like (Fig. 1d) no ka ho'okomo 'ana i ka spectra electrochemical impedance spectroscopy (EIS), a ua hō'ike 'ia nā hualoa'a kūpono ma ka Papa 1. Ua 'ike 'ia nā hapalua pō'ai piha 'ole i ka wā e ho'ā'o ai i ka hā'ina i mālama 'ia a me nā la'ana hana wela, a'o nā hapalua pō'ai i ho'opa'a 'ia i ke anu (Fig. 1b).Ma ka EIS spectrum, hiki ke noʻonoʻo ʻia ka radius semicircle e like me ke kūpaʻa polarization (Rp)25,26.Ma kahi o 135 kΩ cm-2 ka Rp o ka SDSS hoʻonā i mālama ʻia ma ka Papa 1, akā naʻe, no ka SDSS hana wela a me ka ʻōwili anu hiki iā mākou ke ʻike i nā kumu waiwai haʻahaʻa o 34.7 a me 2.1 kΩ cm-2 pakahi.Hōʻike kēia emi nui o ka Rp i ka hopena pōʻino o ka hoʻololi ʻana i ka plastic i ka passivation a me ke kū ʻana i ka corrosion, e like me ka hōʻike ʻana ma nā hōʻike mua 27, 28, 29, 30.
a Nyquist, b, c Bode impedance a me ka māhele kiʻi, a me ka like kaapuni kŘkohu no d, kahi RS ka electrolyte kū'ē, Rp ka polarization kū'ē, a me QCPE 'o ia ka manawa mau mea oxide hoʻohana 'ia e hoʻohālike i ka non-ideal capacitance (n) .Ua hana ʻia nā ana EIS me ka hiki ʻole ke hoʻouka.
Hōʻike ʻia nā ʻōkuhi mua ma ke kiʻikuhi Bode a ʻo ka pālahalaha 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.Hoʻonui ka ʻāpana ʻāpana, e mālama ana i kona waiwai nui ma kahi ākea ākea ākea, a laila emi iho (Fig. 1c).Eia naʻe, ma nā hihia ʻekolu, ʻoi aku ka liʻiliʻi o kēia waiwai nui ma mua o 90 °, e hōʻike ana i kahi ʻano capacitive kūpono ʻole ma muli o ka dispersion capacitive.No laila, hoʻohana ʻia ka QCPE ʻano hana mau (CPE) e hōʻike i ka puʻunaue interfacial capacitance i loaʻa mai i ka ʻeleʻele a i ʻole ka like ʻole o ka ʻili, ʻoi aku ka nui o ke ʻano atomic scale, fractal geometry, electrode porosity, non-uniform potential, and surface dependent current distribution.Electrode geometry31,32.CPE impedance:
kahi j ka helu noonoo a me ω ka alapine huina.ʻO QCPE kahi alapine kūʻokoʻa kūʻokoʻa kūʻokoʻa i ka wahi ākea o ka electrolyte.n he helu mana ʻole e wehewehe ana i ka hoʻokaʻawale ʻana mai ke ʻano capacitive kūpono o ka capacitor, ʻo ia hoʻi ʻo ka kokoke n i ka 1, ʻo ka CPE kokoke i ka capacitance maʻemaʻe, a inā kokoke ka n i ka zero, ʻo ia ke kū'ē.ʻO kahi haʻahaʻa liʻiliʻi o n, kokoke i 1, e hōʻike ana i ka hana capacitive kūpono ʻole o ka ʻili ma hope o ka hoʻāʻo ʻana i ka polarization.ʻOi aku ka kiʻekiʻe o ka QCPE o ka SDSS i ʻōwili ʻia ma mua o nā huahana like, 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, ʻoi aku ka nui o ka Cr maʻiʻo o SDSS ma ke ʻano he ʻoi aku ka maikaʻi o ka pale ʻana i ka corrosion o SDSS ma muli o ka loaʻa ʻana o kahi kiʻiʻoniʻoni pale pale passive ma ka ʻili17.Nui ka waiwai o kēia kiʻiʻoniʻoni passivating i nā Cr3+ oxides a/a i ʻole hydroxides, ka nui o ka hoʻohui ʻana i nā Fe2+, Fe3+ oxides a/a i ʻole (oxy)hydroxides 33.ʻOiai ka like like o ka ili, ka passivating oxide layer, a ʻaʻohe mea i ʻike ʻia ma ka ʻili, e like me ka mea i hoʻoholo ʻia e nā kiʻi microscopic, 6,7 ʻokoʻa ka hana corrosion o ka SDSS wela a me ke anuanu a no laila pono e aʻo hohonu i ka microstructure deformation a me ke ʻano o ke kila.
Ua noiʻi nui ʻia ka microstructure o ke kila stainless deformed me ka hoʻohana ʻana i nā kukui X-ʻenehana kiʻekiʻe o loko a me synchrotron (Nā Kiʻi Hoʻohui 1, 2).Hāʻawi ʻia kahi ʻike kikoʻī ma ka ʻIke Hoʻohui.ʻOiai ua pili nui lākou i ke ʻano o ka māhele nui, ʻike ʻia nā ʻokoʻa o nā hakina puʻupuʻu puʻupuʻu, i helu ʻia ma ka Pākuʻi Pākuʻi 1. Hiki ke hoʻopili ʻia kēia mau ʻokoʻa me nā hakina māhele like ʻole ma ka ʻili, a me nā hakina māhele volumetric i hana ʻia ma nā hohonu like ʻole.ʻike ʻia e ka ʻokoʻa X-ray.(XRD) me nā kumu ikehu like ʻole o nā photons hanana.ʻO ka māhele kiʻekiʻe aʻe o ka austenite i loko o nā mea hoʻoheheʻe anuanu, i hoʻoholo ʻia e XRD mai kahi kumu hoʻokolohua, e hōʻike ana i ka passivation ʻoi aku ka maikaʻi a ʻoi aku ka maikaʻi o ka pale ʻana i ka corrosion35, ʻoiai ʻoi aku ka pololei a me nā hualoaʻa helu helu e hōʻike i nā ʻano kūʻē i nā māhele 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.Hōʻike nā mea hana wela i ke ʻano o ka palaoa, e hōʻike ana i ka nui o nā hua micron, ʻoiai nā apo laulima i ʻike ʻia i loko o nā ʻano mea i ʻōwili ʻia (Supplementary Fig. 3) e hōʻike ana i ka hoʻomaʻemaʻe palaoa nui i ka nanoscale i ka hana mua6, pono e kōkua i ka passivation film.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 nā mokuʻāina kemika o nā microdomains o nā mea haʻahaʻa me ka hoʻohana ʻana i ka X-PEEM.ʻOiai ka nui o nā mea hoʻohuihui, ua koho ʻia ʻo Cr, Fe, Ni a me Ce39 ma ʻaneʻi, ʻoiai ʻo Cr kahi mea koʻikoʻi no ka hoʻokumu ʻana i kahi kiʻiʻoniʻoni passivation, ʻo Fe ka mea nui i ke kila, a hoʻonui ʻo Ni i ka passivation a me ke kaupaona ʻana i ke ʻano ferrite-austenitic phase a me ke kumu o ka hoʻololi ʻana o Ce.Ma ka hoʻoponopono ʻana i ka ikehu o ka radiation synchrotron, ua uhi ʻia ka RAS mai ka ʻili me nā hiʻohiʻona nui o Cr (kaʻe L2.3), Fe (ka L2.3), Ni (ka L2.3) a me Ce (ka M4.5).ʻO ka hana wela a me ka ʻōwili anu Ce-2507 SDSS.Hana ʻia ka ʻikepili kūpono ma o ka hoʻohui ʻana i ka hoʻohālikelike ikehu me ka ʻikepili i paʻi ʻia (e laʻa me XAS 40, 41 ma Fe L2, 3 ʻaoʻao).
Ma ka fig.Hōʻike ka Figure 2 i nā kiʻi X-PEEM o ka hana wela (Fig. 2a) a me ke anuanu (Fig. 2d) Ce-2507 SDSS a me nā ʻaoʻao XAS kūpono o Cr a me Fe L2,3 ma nā wahi i kaha ʻia.Ke huli nei ka lihi L2,3 o ka XAS i nā mokuʻāina 3d i noho ʻole ʻia ma hope o ka photoexcitation electron ma nā pae hoʻokaʻawale spin-orbit 2p3/2 (L3 lihi) a me 2p1/2 (L2 lihi).Loaʻa ka ʻike e pili ana i ke kūlana valence o Cr mai XAS ma ka ʻaoʻao L2,3 ma Fig. 2b, e.Hoʻohālikelike me nā luna kānāwai.42,43 hōʻike i ʻehā mau piko i ʻike ʻia ma kahi kokoke i ka ʻaoʻao L3, i kapa ʻia ʻo A (578.3 eV), B (579.5 eV), C (580.4 eV) a me D (582.2 eV), e hōʻike ana i ka octahedral Cr3+, e pili ana i ka ion Cr2O3.Ua ʻae ka spectra hoʻokolohua me nā helu kumu i hōʻike ʻia ma nā panela b a me e, i loaʻa mai nā helu he nui o ke kahua aniani ma ka Cr L2.3 interface 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 X-PEEM o SDSS hoʻoheheʻe wela e pili ana i ka b Cr L2.3 lihi a me c Fe L2.3 lihi, d X-PEEM kiʻi wela o ka SDSS wili anu e pili ana i e Cr L2.3 lihi a me f Fe L2 .3 ʻaoʻao lihi ( f).Hoʻolālā ʻia ke kikoʻī XAS ma nā kūlana spatial like ʻole i kaha ʻia ma nā kiʻi wela (a, d), nā laina kikoʻī ʻalani ma (b) a me (e) e hōʻike ana i ka spectra XAS i hoʻohālikelike ʻia o Cr3+ me kahi waiwai māla kristal o 2.0 eV.No nā kiʻi X-PEEM, e hoʻohana i ka 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).
Me ka nānā ʻole i ke kaiapuni kemika o kēia mau mea metala, ʻaʻole i loli ke kūlana kemika o nā mea hoʻohui Ni a me Ce no nā mea hoʻohālike ʻelua.Kiʻi hou aku.Hōʻike nā kiʻi 5-9 i nā kiʻi X-PEEM a me nā kikoʻī XAS kūpono no Ni a me Ce ma nā kūlana like ʻole ma luna o ka ʻili o nā mea hoʻohālike i hana ʻia me ka wela a me ke anu.Hōʻike ʻo Ni XAS i nā mokuʻāina oxidation o Ni2+ ma luna o ka ʻili holoʻokoʻa i ana ʻia o nā mea hoʻohālike i hana ʻia me ka wela a me ke anu (Hoʻohui Kūkākūkā).Pono e hoʻomaopopoʻia, ma keʻano o nā mea hana wela,ʻaʻole iʻikeʻia ka hōʻailona XAS o Ce,ʻoiai ma keʻano o nā'ōpana anuanu, uaʻikeʻia ka spectrum o Ce3 +.ʻO ka nānā ʻana i nā kiko Ce i loko o nā laʻana i ʻōwili ʻia i ke anu i hōʻike ʻia e ʻike nui ʻia ʻo Ce ma ke ʻano o nā precipitates.
I loko o ka SDSS thermally deformed, ʻaʻole i ʻike ʻia kahi hoʻololi kūloko kūloko ma XAS ma ka ʻaoʻao Fe L2,3 (Fig. 2c).Eia naʻe, hoʻololi ka Fe matrix micro-regionally i kona kūlana kemika ma ʻehiku mau wahi i koho ʻole ʻia o ka SDSS i ʻōwili ʻia anu, e like me ka hōʻike ʻana ma ka Fig. 2f.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 ho'ohālike 'ia ka XAS spectra o ka Fe L2,3 lihi o α-Fe2O3 system a me Fe2+ octahedral oxides e ka helu 'ana i ka mala aniani me ka ho'ohana 'ana 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 o ka α-Fe2O3 a me ka γ-Fe2O3, Fe3O4 i hui pū ʻia o Fe2+ & Fe3+,47, a me FeO45 ma ke ʻano he Fe2+ oxide (3d6) formally divalent.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 i hui pū ʻia o Fe2+ a me Fe3+,47 a ʻo FeO45 e hana ma ke ʻano he divalent Fe2+ oxide (3d6).Loaʻa i nā ion Fe3+ a pau i loko o α-Fe2O3 nā kūlana Oh wale nō, ʻoiai ʻo γ-Fe2O3 ka mea maʻamau e hōʻike ʻia e 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 pepa mua, ʻo 45 ʻoiai ʻokoʻa ka lākiō ikaika o nā mea ʻelua, ʻo ko lākou ʻano ikaika eg / t2g ʻo ≈1, ʻoiai ma kēia ʻano ʻike ʻia ka lākiō ikaika eg / t2g e pili ana i 1. ʻAʻole kēia i ka hiki ke loaʻa i kēia kūlana Fe3 + wale nō.E noʻonoʻo ana i ka hihia o Fe3O4 me nā Fe2 + a me Fe3 +, ʻo ka hiʻohiʻona mua i ʻike ʻia he nāwaliwali (ikaika) L3 lihi no Fe e hōʻike ana i kahi mokuʻāina liʻiliʻi (nui) t2g.Pili kēia iā Fe2+ (Fe3+), e hōʻike ana i ka hiʻohiʻona mua o ka hoʻonui e hōʻike ana i ka piʻi ʻana o ka ʻike o Fe2+47.Hōʻike kēia mau hopena i ka noho like ʻana o Fe2+ a me γ-Fe2O3, α-Fe2O3 a me / a i ʻole Fe3O4 e noho aliʻi ma luna o ka ʻili anuanu o nā mea hoʻohui.
Hoʻonui ʻia nā kiʻi kiʻi kiʻi wela o ka XAS spectra (a, c) a me (b, d) e hele ana i 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.
Hoʻopili ʻia nā ʻikepili hoʻokolohua i loaʻa (Fig 4a a me Fig.ʻO ka kikoʻī, ʻike ʻia ka spectrum 2-a (i hōʻike ʻia ʻo XAS-1) ma ke kiʻi 3b a ukali ʻia e ka spectrum 2-b (kapa ʻia ʻo XAS-2) ma luna o ka ʻāpana ʻike holoʻokoʻa, ʻoiai ʻike ʻia ka spectra e like me E-3 ma ke kiʻi 3d (labeled XAS-3) i nā wahi kikoʻī.E like me ke kānāwai, ua hoʻohana ʻia nā ʻāpana ʻehā no ka ʻike ʻana i nā mokuʻāina valence i loaʻa i ka hāpana ma lalo o ke aʻo ʻana: (1) nā hiʻohiʻona spectral L3 a me L2, (2) nā kūlana ikehu o nā ʻano L3 a me L2, (3) ʻokoʻa ikehu L3-L2., ( 4) L2/L3 hoʻoikaika ikaika.Wahi a nā ʻike maka (Fig. 4a), aia nā ʻāpana Fe ʻekolu, ʻo ia hoʻi, Fe0, Fe2+, a me Fe3+, aia ma ka ʻili SDSS ma lalo o ke aʻo ʻana.Ua hōʻike pū ʻia ka lākiō ikaika L2/L3 i ka loaʻa ʻana o nā ʻāpana ʻekolu.
a Simulated XAS spectra o Fe me ka ike ekolu okoa hoʻokolohua 'ikepili (paʻa laina XAS-1, XAS-2 a me XAS-3 kulike me 2-a, 2-b a me E-3 ma Fig. 2 a me 3) Hoʻohālikelike , Octahedrons Fe2 +, Fe3 + me ka kristal kahua waiwai o 1.0 eV a me XAS-3 ana, ka 1.0 eV a me ka 1.5 eV. AS-3) a me ka ʻikepili LCF i hoʻopaʻa ʻia (laina ʻeleʻele paʻa), a ma ke ʻano XAS-3 spectra me Fe3O4 (ke aupuni hui ʻia o Fe) a me Fe2O3 (fe3+ maʻemaʻe).
Ua hoʻohana ʻia kahi laina hui kūpono (LCF) o nā kūlana ʻekolu 40, 41, 48 no ka helu ʻana i ka haku ʻana o ka hao oxide.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 mea hoʻopili LCF, ua mālama ʻia ʻo 10% Fe0 i nā hihia āpau ma muli o ka ʻike ʻana i kahi liʻiliʻi liʻiliʻi i nā ʻikepili āpau, a no ka mea ʻo ka hao metala 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 ужить 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.事实上,X-PEEM 对Fe(~6 nm)49 的检测深度大于估计的氧化层厚度(略> 4 nm),允许来杀话铁基体(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) 允记层 下方 铁基体 (fe0) 的。 信号 信号 信号 信号 信号 信号 信号 信号 信号 信号 信号Фактически, глубина обнаружения Fe (~ 6 нм) 49 с помощью X-PEEM больше, чем предполагаемая толщина оксиного (по сидного) оляет обнаруживать сигнал от железной матрицы (Fe0) ниже пассивирующего слоя. ʻO ka ʻoiaʻiʻo, ʻoi aku ka hohonu o ka ʻike ʻana o Fe (~ 6 nm) 49 e X-PEEM ma mua o ka mānoanoa i manaʻo ʻia o ka papa oxide (liʻiliʻi > 4 nm), e hiki ai ke ʻike i ka hōʻailona mai ka matrix 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 4b i ka spectrum XAS-1 no ka hui pū ʻana o Fe2+ a me Fe3+, kahi i like ai nā ʻāpana o Fe2+ a me Fe3+ ma kahi o 45%, e hōʻike ana i nā mokuʻāina hoʻoheheʻe 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.ʻO ka Fe2+ ​​ua emi iho ma mua o Fe3+.ʻO ka lakio o Fe2+ me Fe3, like me 1:2, ʻo ia hoʻi, hiki ke hana ʻia ʻo Fe3O4 ma ka ratio like ma waena o nā ion Fe.Eia hou, no ka XAS-3 spectrum, ka pakeneka o Fe2 + a me Fe3 + lilo 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 hoʻomaopopo ʻana i ke kumu kūpono loa o Fe3+, ua hoʻolālā ʻia ka spectrum XAS-3 me nā ʻokoʻa Fe3+ ma ke kiʻi 4e, e hōʻike ana i ka like me nā kūlana ʻelua i ka wā e noʻonoʻo ai i ka piko B.Eia naʻe, hōʻike ka ikaika o nā poʻohiwi kiʻekiʻe (A: mai Fe2 +) a me ka lākiō ikaika B / A ua kokoke ke kiko o XAS-3, akā ʻaʻole i kūlike me ka spectrum o γ-Fe2O3.Ke hoʻohālikelikeʻia me ka nui γ-Fe2O3,ʻo ka Fe 2p XAS peak o A SDSS heʻoi aʻe ka ikaika (Fig. 4e), e hōʻike ana i ka ikaika kiʻekiʻe o Fe2 +.ʻOiai ua like ka spectrum o XAS-3 me ka γ-Fe2O3, kahi Fe3+ aia ma nā kūlana Oh a me Td, ʻo ka ʻike ʻana o nā mokuʻāina valence like ʻole a me ka hoʻohui ʻana wale nō ma ka ʻaoʻao L2,3 a i ʻole ka L2/L3 ikaika lākiō e mau nei ke kumuhana o ka noiʻi mau.kūkākūkā ma muli o ka paʻakikī o nā mea like ʻole e pili ana i ka spectrum hope41.
Ma waho aʻe o nā ʻokoʻa kikoʻī i ke kūlana 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 ʻili hoʻohālike me ka hoʻohana ʻana i ke ʻano clustering K-means.Hoʻokumu nā ʻaoʻao ʻaoʻao Cr L i ʻelua puʻupuʻu maikaʻi loa i puʻunaue ʻia i loko o nā mea hoʻohālike i hana ʻia me ka wela a me ke anuanu i hōʻike ʻia ma Fig.5. Akaka, 'a'ole i 'ike 'ia ka ho'ololi 'ana o ke kūkulu 'ana i ka 'āina, no ka mea, ua like nā kikowaena 'elua o ka spectra XAS Cr.ʻO kēia mau hiʻohiʻona hiʻohiʻona o nā pūʻulu ʻelua ua ʻaneʻane like me nā mea e pili ana iā Cr2O342, ʻo ia hoʻi, ʻo nā ʻāpana Cr2O3 e pili pono ana i ka SDSS.
ʻO Cr L K-ʻo ia hoʻi nā pūʻulu ʻāpana lihi, a ʻo b nā kikowaena XAS pili.Nā hualoaʻa o ka hoʻohālikelike K-means X-PEEM o SDSS i ʻōwili anuanu: c Cr L2.3 ʻāpana kihi o nā pūʻulu K-means a me nā kikowaena XAS e pili ana.
No ka hōʻike ʻana i nā palapala ʻaoʻao FeL ʻoi aku ka paʻakikī, ua hoʻohana ʻia nā puʻupuʻu ʻehā a me ʻelima a me ko lākou mau kikowaena pili (spectral profiles) no nā mea hoʻohālike i hana ʻia me ka wela a me ke anuanu.No laila, hiki ke loaʻa ka pākēneka (%) o Fe2+ a me Fe3+ ma ke kau 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 \(\rm{E}_{\rm{Fe}/\rm{Fe}^{2 + (3 + )}}\) i like me \(\rm{Fe} + 2e^ – \ i \rm { Fe}^{2 + (3 + )}\), 0.440 a me 0.036 V, pakahi.Loaʻa i nā ʻāpana me ka haʻahaʻa haʻahaʻa ka ʻike o ka hui Fe3+.ʻO ka hāʻawi ʻana i nā mea hoʻohālike thermally deformed he ʻano layered me ka loli 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 i hilinaʻi ʻia i ke kūlana i loko o ka laminar i lalo (Fig. 6b).ʻO ka mea'ē aʻe, no ka hoʻohuiʻana i nā meaʻokoʻa likeʻole me nā mea likeʻole o Fe2 + a me Fe3 + i loko o ka SDSS i'ōwiliʻia, hiki ke nānā i kahiʻano likeʻole o ka pseudopotential (Fig. 6c, d).ʻO Fe3+ oxides a/a i ʻole (oxy)hydroxides ka mea nui o ka ʻōpala i loko o ke kila a hiki i ka oxygen a me ka wai50.I kēia hihia, ua manaʻo ʻia nā mokupuni waiwai i ka Fe3+ ua māhele ʻia i ka ʻāina a hiki ke manaʻo ʻia he mau wahi ʻino.I ka manawa like, hiki ke hoʻohana ʻia ka gradient i ke kahua kūpono, ma mua o ka waiwai piha o ka hiki, i mea hōʻailona no ka localization o nā wahi corrosion ikaika.Hiki i kēia māhele like ʻole o Fe2+ a me Fe3+ ma ka ʻili o ka SDSS ʻōwili anuanu ke hoʻololi i ka kemika kūloko a hāʻawi i kahi ʻāpana ʻoi aku ka hana i ka wā o ka haki ʻana o ka kiʻiʻoniʻoni oxide a me nā hopena corrosion, e ʻae ana i ka matrix metala lalo e hoʻomau i ka ʻino, e hopena i ka heterogeneity kūloko.nā waiwai a ho'ēmi i nā mea pale o ka papa passivating.
ʻO nā pūʻulu K-means a me nā kikowaena XAS e pili ana i ka ʻāpana Fe L2.3 o ka X-PEEM ac a me ka df o ka SDSS i ʻōwili anuanu.a, d K-means cluster plots i uhi ʻia ma nā kiʻi X-PEEM.ʻO ka pseudoelectrode hiki i helu ʻia (Epseudo) i ʻōlelo ʻia me ka K-means cluster plot.ʻO ka ʻōlinolino o ke kiʻi X-PEEM, e like me ke kala ma ka Fig.
ʻO ka ʻokoʻa like ʻole o ka Cr akā ke ʻano kemika ʻokoʻa o Fe ke alakaʻi i nā pōʻino kiʻiʻoniʻoni oxide a me nā ʻano corrosion ma ka Ce-2507 i hana ʻia me ka wela a me ke anuanu.Ua aʻo maikaʻi ʻia kēia waiwai o ke anuanu Ce-2507.E pili ana i ka hana ʻana o nā oxides a me nā hydroxides o Fe i loko o ka ea ambient i kēia hana ʻaneʻane kū ʻole, penei nā hopena:
Loaʻa nā hopena i luna ma nā hiʻohiʻona aʻe e pili ana i ka loiloi X-PEEM.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 ka hopena i ka hoʻokumu ʻana i kahi papa Fe(OH)2 (equation (5)), e hoʻonui ai i ka hōʻailona Fe2+ i ka Fe L-edge XAS.ʻO ka hoʻolōʻihi ʻia ʻana i ka ea hiki ke hopena i ka hoʻokumu ʻana o Fe3O4 a/a i ʻole Fe2O3 oxides ma hope o Fe(OH)252,53.ʻElua mau ʻano paʻa o Fe, Fe3O4 a me Fe2O3, hiki ke hana ʻia i loko o ka Cr3+ waiwai pale pale, kahi e makemake ai ʻo Fe3O4 i kahi ʻano like a paʻa.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 ka nānā ʻana o XAS-3 spectra ma nā wahi he nui i hōʻike i ka hoʻololi piha ʻana i γ-Fe2O3.No ka mea, ʻo ka hohonu o ke komo ʻana o nā kukui X i wehe ʻia ma kahi o 50 nm, ʻo ka hōʻailona mai ka papa haʻahaʻa e loaʻa ai ka ikaika kiʻekiʻe o ka piko A.
Hōʻike ka spectrum XPA i ka ʻāpana Fe i loko o ke kiʻiʻoniʻoni oxide i kahi ʻano papa i hui pū ʻia me kahi papa Cr oxide.He ʻokoʻa i nā hōʻailona o ka passivation ma muli o ka inhomogeneity kūloko o Cr2O3 i ka wā o ka corrosion, ʻoiai ke ʻano o ka ʻāpana like o Cr2O3 i kēia hana, ʻike ʻia ke kūpaʻa haʻahaʻa haʻahaʻa i kēia hihia, ʻoi aku hoʻi no nā specimens ʻōwili anuanu.Hiki ke hoʻomaopopo ʻia ke ʻano i ʻike ʻia ʻo ka heterogeneity o ke kūlana hoʻokahe kemika ma ka papa luna (Fe), e pili ana i ka hana corrosion.Ma muli o ka like stoichiometry o ka papa luna (iron oxide) a me ka papa haʻahaʻa (chromium oxide) 52,53 ʻoi aku ka maikaʻi o ka launa ʻana (adhesion) ma waena o lākou e alakaʻi i ka lawe lohi ʻana o nā metala a i ʻole oxygen i loko o ka lattice, ka mea, ke alakaʻi nei i ka hoʻonui ʻana i ke kūpaʻa corrosion.No laila, ʻoi aku ka maikaʻi o ka lākiō stoichiometric mau, ʻo ia hoʻi, hoʻokahi kūlana oxidation o Fe, ma mua o nā hoʻololi stoichiometric.ʻO ka SDSS i hoʻoheheʻe ʻia me ka wela he ʻano like ʻole o ka ʻili, kahi pale pale ʻoi aku ka nui, a ʻoi aku ka maikaʻi o ka pale ʻana i ka corrosion.No ka SDSS wili anu, o ka noho ana o na mokupuni Fe3+-waiwai ma lalo o ka papa pale e uhai ana i ka pono o ka ili a me ka poino galvanic me ka substrate kokoke, e alakai ana i ka kulu oi o Rp (Pakaukau 1).Hoʻemi ʻia ka spectrum EIS a me kona pale ʻana i ka corrosion.Hiki ke ʻike ʻia ʻo ka hāʻawi ʻia ʻana o nā mokupuni waiwai Fe3+ ma muli o ka hoʻololi ʻana i ka plastic e pili nui ana i ka pale ʻana i ka corrosion, ʻo ia ka hopena o kēia hana.No laila, hōʻike kēia haʻawina i nā kiʻi microscopic spectroscopic o ka hoʻemi ʻana i ka pale ʻana i ka corrosion o nā laʻana SDSS i aʻo ʻia e ke ʻano deformation plastic.
Eia kekahi, ʻoiai ʻoi aku ka maikaʻi o ka hoʻohui ʻana o ka honua i nā ʻāpana ʻelua, ʻoi aku ka paʻakikī o ka launa ʻana o kēia mea hoʻohui me ka matrix kila hoʻokahi e pili ana i ka hana corrosion e like me spectroscopic microscopy.ʻO ka hiʻohiʻona o nā hōʻailona Ce (ma XAS M-edges) ʻike wale ʻia ma nā wahi liʻiliʻi i ka wā o ka ʻōwili anu, akā nalo i ka wā o ka deformation wela o ka SDSS, e hōʻike ana i ka ua kūloko o Ce i ka matrix kila, ma mua o ka hoʻohuihui homogeneous.ʻOiai ʻaʻole i hoʻomaikaʻi nui i nā waiwai mechanical o SDSS6,7, ʻo ka loaʻa ʻana o nā mea ʻeleʻele ʻeleʻele e hōʻemi i ka nui o nā inclusions a manaʻo ʻia e kāohi i ka lua i ka māhele mua54.
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.Pane mākou i ka nīnau no ke aha e ʻino ai ke kila kuhiliʻole ma lalo o kahi ʻāpana oxide pale ma ka helu ʻana i kona microstructure, kemika ʻili, a me ka hoʻoili hōʻailona me ka hoʻohana ʻana i ka hui K-means.Ua hoʻokumu ʻia ʻo nā mokupuni waiwai i ka Fe3+, me kā lākou octahedral a me tetrahedral coordination ma ka hiʻohiʻona holoʻokoʻa o Fe2+/Fe3+ i hui pū ʻia, ʻo ia ke kumu o ka pōʻino a me ka corrosion o ka SDSS kiʻi ʻoniʻoni anuanu.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 ka holomua metodological i ka hoʻoholo ʻana i ka hopena o ka heterogeneity kemika nanoscale i ka corrosion, manaʻo ʻia ka hana hoʻomau e hoʻoulu i nā kaʻina hana ʻenehana e hoʻomaikaʻi i ke kūpaʻa corrosion o nā kila kila i ka wā o ka hana kila.
No ka hoʻomākaukau ʻana i ka Ce-2507 SDSS ingot i hoʻohana ʻia i kēia haʻawina, ua hoʻoheheʻe ʻia kahi haku mele Fe-Ce master alloy i hoʻopaʻa ʻia me kahi paipu hao maʻemaʻe i loko o 150 kg medium frequency induction furnace e hana ai i ke kila hoʻoheheʻe ʻia a ninini ʻia i loko o ka mold.Hoʻopaʻa ʻia nā hui kemika i ana ʻia (wt%) ma ka Papa Pākuʻi 2. Hoʻolima mua ʻia nā Ingots i mau poloka.A laila ua hoʻopili ʻia ma 1050 ° C no 60 min e loaʻa ai ke kila ma ke ʻano o kahi hopena paʻa, a laila kinai ʻia i loko o 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.
Ua hana ʻia nā laʻana cylindrical (φ10 mm × 15 mm) no ka hoʻopili wela i mea e like ai ke axis o ka cylinder me ke kuhikuhi deformation o ka poloka.Ua hoʻokō ʻia ka paʻi kiʻekiʻe ma nā wela like ʻole ma ka laulā o 1000-1150 ° C me ka hoʻohana ʻana i kahi simulator thermal Gleeble-3800 ma kahi pānaʻi paʻa mau ma ka laulā o 0.01-10 s-1.Ma mua o ka hoʻololi ʻana, ua hoʻomehana ʻia nā mea hoʻohālike ma kahi o 10 °C s-1 no 2 min ma kahi mahana i koho ʻia e hoʻopau i ka gradient mahana.Ma hope o ka loaʻa ʻana o ka like ʻana o ka mahana, ua hoʻololi ʻia ka hāpana i kahi waiwai kānana maoli o 0.7.Ma hope o ka deformation, ua kinai koke ʻia nā laʻana me ka wai no ka mālama ʻana i ka hale deformed.A laila ʻoki ʻia ke ʻano mea paʻakikī e like me ke kuhikuhi ʻana.No kēia noiʻi ponoʻī, ua koho mākou i kahi hōʻailona me kahi kūlana wela wela o 1050°C, 10 s-1 no ka mea ʻoi aku ka kiʻekiʻe o ka microhardness i ʻike ʻia ma mua o nā specimens7.
Nui (80 × 10 × 17 mm3) nā laʻana o ka Ce-2507 solid solution i hoʻohana ʻia i loko o ka LG-300 ʻekolu-phase asynchronous two-roll mill me nā waiwai mechanical maikaʻi loa ma waena o nā pae deformation ʻē aʻe a pau6.ʻO ka 0.2 m·s-1 a me 5% ka nui o ka mānoanoa no kēlā me kēia ala.
Ua hoʻohana ʻia kahi kahua hana electrochemical Autolab PGSTAT128N no nā ana electrochemical SDSS ma hope o ka ʻōwili anuanu a hiki i 90% ka hoʻemi ʻana i ka mānoanoa (1.0 e like me ke kānana ʻoiaʻiʻo) a ma hope o ke kaomi wela ma 1050°C no 10 s-1 i kahi kānana maoli o 0.7.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 laʻana i loko o nā cylinders me ke anawaena o 11.3 mm, i nā ʻaoʻao i hoʻopaʻa ʻia nā uea keleawe.A laila ua hoʻopaʻa ʻia nā laʻana me ka epoxy, e waiho ana i kahi ākea hana o 1 cm2 ma ke ʻano he electrode hana (ʻaoʻao lalo o ka sample cylindrical).E akahele i ka wā e ho'ōla ai i ka epoxy a me ka hoʻomaʻamaʻa ʻana a me ka hoʻoliʻiliʻi ʻana e pale aku i ka haki ʻana.Hoʻopili ʻia nā papa hana i ka lepo a hoʻomāliʻi ʻia me ka hoʻokuʻu ʻia ʻana o ke daimana me ka nui o 1 μm, holoi ʻia me ka wai 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.Hoʻohana ʻia kahi ʻano wai wai o FeCl3 (6.0 wt%), i hoʻopaʻa ʻia i ka pH = 1.0 ± 0.01 me HCl e like me nā ʻōlelo aʻoaʻo a ASTM, i hoʻohana ʻia e hoʻolalelale i ka ʻino ʻana o ke kila kila55 no ka mea he mea ʻino ia i mua o nā ion chloride me ka mana oxidizing ikaika a me ka pH haʻahaʻa Nā kūlana kūlohelohe G48 a me A92.E hoʻokomo i ka hāpana i loko o ka hoʻonā hoʻāʻo no 1 hola a hiki i kahi kūlana paʻa ma mua o ka hana ʻana i kekahi ana.No ka paʻa paʻa, wela-hana, a me ke anu-owili laʻana, impedance ana i lawe 'ia ma hamama kaapuni hiki (OPC) o 0.39, 0.33, a me 0.25 V, pakahi, ma ka alapine (frequency) mai 1 105 a 0.1 Hz me ka amplitude o 5 mV.Ua hana hou ʻia nā hoʻokolohua kemika a pau ma kahi o 3 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 me ke ana ʻana he 1 × 1 × 1.5 mm3 no ka hoʻohālikelike ʻana i ka haku mele ʻana o kahi mea hoʻoheheʻe ikaika kiʻekiʻe o Brockhouse ma CLS, Canada56.Ua lawe ʻia ka hōʻiliʻili ʻikepili ma Debye-Scherrer geometry a i ʻole ka hoʻouna ʻana i ka geometry ma ka lumi wela.ʻO ka lōʻihi nalu X-ray i hoʻopaʻa ʻia me ka LaB6 calibrator 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 hana X-ray.Aia 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 nā ʻikepili āpau 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 s a me 120 mau kiʻi.
Ua hoʻokō ʻia nā ana X-PEEM o ʻelua ʻōnaehana hoʻohālike i koho ʻia ma ka Beamline MAXPEEM PEEM hopena hope 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.Ua loaʻa ka hoʻonā ikehu o ka laina kukuna ma ke ana ʻana i ka spectrum hua ion ma ka ʻāpana hoʻohiwahiwa mai N 1 s a i 1 \ (\ pi _g^ \ast\) kokoke i hv = 401 eV ma N2 me ka hilinaʻi o ka ikehu photon ma E3/2 , 57. Hāʻawi ʻia ke kiko kikoʻī e pili ana i ka Δ0. 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. , 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 L.32 edge, Nic2p L2. , a me Ce M4.5 lihi. Таким образом, энергетическое разрешение канала пучка было оценено как E/∆E = 700 эВ/0,3 эВ > 2000 и/10лі ≤ 10 ≤ LIKE LIKE LIKE 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 1200 laina / mm no Fe lihi 2p L2,32, Cr lihi 2p L2,32, Cr2 lihi a me Cr2. 4.5.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,通过使版 1 mm 因此 0.3 eV栅的改进的SX-700 单色器用于Fe 2p L2,3 边缘、Cr 2p L2,3 边缘、Ni 2p L2,3 边缘和Ce M4,5 边缘和Ce M4,5 。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 , 使禔 , 使禔mm-1 光栅 改进 的 SX-700 单色器 于 于 于 用 用 用Fe 2p L2.3 边缘、Cr 2p L2.3 边缘边缘、Ni.边缘。No laila, i ka wā e hoʻohana ai i kahi monochromator SX-700 i hoʻololi ʻia me ka laina 1200 Si grating.3, Cr lihi 2p L2.3, Ni lihi 2p L2.3 a me Ce lihi M4.5.E nānā 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 fiber-coupled CMOS detector me 2 x 2 bins, e hāʻawi ana i kahi hoʻonā o 1024 × 1024 pixels ma kahi kahua ʻike 20 µm.ʻO ka manawa hoʻolaha o nā kiʻi he 0.2 s, he 16 mau kiʻi ma waena.Koho ʻia ka ikehu kiʻi photoelectron ma ke ʻano e hāʻawi ai i ka hōʻailona electron lua kiʻekiʻe.Hoʻohana ʻia nā ana a pau ma ka hoʻohana ʻana i kahi kukuna photon linearly polarized.Hiki ke loaʻa ka ʻike hou aku e pili ana i nā ana ma kahi haʻawina mua.Ma hope o ka hoʻopaʻa ʻana i ke ʻano ʻike electron yield (TEY) a me kāna noi ma X-PEEM49, ua manaʻo ʻia ka hohonu hoʻāʻo o kēia ʻano ma kahi o 4-5 nm no ka hōʻailona Cr a ma kahi o 6 nm no Fe.ʻO ka hohonu Cr kahi kokoke loa i ka mānoanoa o ke kiʻi oxide (~ 4 nm) 60,61 ʻoiai ʻo ka hohonu Fe ʻoi aku ka nui ma mua o ka mānoanoa.ʻO XRD i hōʻiliʻili ʻia ma ka ʻaoʻao o Fe L he hui pū ʻia o XRD o nā mea hao hao a me Fe0 mai ka matrix.I ka hihia mua, hiki mai ka ikaika o nā electrons i hoʻokuʻu ʻia mai nā ʻano electrons hiki ke kōkua 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 a hiki i ka ʻili a e hōʻiliʻili ʻia e ka mea nānā.I kēia hihia, ʻo ka hōʻailona Fe0 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 ke ala pakele electron, e hōʻemi hou ana i ka pane spectral Fe0 i ka palapala hao XAS.
ʻO ka hoʻohui ʻana i ka ʻili ʻikepili i loko o kahi cube data (X-PEEM data) kahi hana koʻikoʻi i ka unuhi ʻana i ka ʻike pili (kemika a i ʻole nā ​​waiwai kino) ma ke ʻano multidimensional.Hoʻohana nui ʻia ʻo K-means clustering ma nā ʻano he nui, e like me ka ʻike mīkini, ka hoʻoili kiʻi, ka ʻike ʻana i ke ʻano ʻike ʻole, ka naʻauao hana, a me ka nānā ʻana i ka classificatory.No ka laʻana, ua hana maikaʻi ʻo K-means clustering i ka clustering hyperspectral kiʻi ʻikepili.Ma ke kumu, no ka ʻikepili multi-feature, hiki i ka K-means algorithm ke hui maʻalahi iā lākou ma muli o ka ʻike e pili ana i ko lākou mau ʻano (photon energy properties).ʻO ka K-means clustering he algorithm iterative no ka puʻunaue ʻana i nā ʻikepili i loko o nā pūʻulu K non-overlapping (clusters), kahi o kēlā me kēia pika i kahi puʻupuʻu kikoʻī e pili ana i ka puʻunaue spatial o ka inhomogeneity kemika i loko o ke kila microstructural haku.Aia i loko o ka K-means algorithm nā pae ʻelua: i ka pae mua, helu ʻia nā K centroids, a ma ka pae ʻelua, ua hāʻawi ʻia kēlā me kēia kiko i kahi pūpū me nā centroids kokoke.Ua wehewehe ʻia ke kikowaena o ka ʻumekaumaha o kahi pūpū ma ke ʻano he helu helu o nā helu ʻikepili (XAS spectrum) no kēlā pūʻulu.Aia nā mamao like ʻole e wehewehe i nā kikowaena pili e like me ka mamao Euclidean.No kahi kiʻi hoʻokomo o px,y (kahi o 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 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 ikaika ʻia nā hopena maikaʻi o ka clustering me ke koho maikaʻi loa o nā centroids mua.No ka hoʻolālā ʻikepili PEEM o nā kiʻi kila, ʻo X (x × y × λ) ka mea maʻamau he cube o ka ʻikepili array 3D, ʻoiai nā koʻi x a me y e hōʻike ana i ka ʻike kikoʻī (pixel resolution) a ʻo ke axis λ e pili ana i kahi photon.kiʻi spectral ikehu.Hoʻohana ʻia ka algorithm K-means e ʻimi 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 kā lākou mau hiʻohiʻona spectral a me ka unuhi ʻana i nā centroids maikaʻi loa (XAS spectral profiles) no kēlā me kēia analyte.pūʻulu).Hoʻohana ʻia ia e aʻo i ka hāʻawi ʻana i ka spatial, nā loli spectral kūloko, ka hana oxidation, a me nā 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 nā pūʻulu K (nā ʻāpana o ka microstructure) e ʻike i nā pūʻulu kūpono a me nā centroids.Ke hōʻike ʻia kēia mau helu, hāʻawi hou ʻia nā pika i nā centroid cluster pili.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 ma muli o ke noi kūpono mai ka mea kākau WC.
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Ka manawa hoʻouna: Oct-24-2022