Kev tshawb fawb rau Corrosion Resistance ntawm Kub dipped Galvalume Txheej

Kub-dipped Zn55Al1.6Si galvalume coatings tau dav siv nyob rau hauv ntau lub teb xws li tsheb kev lag luam, shipbuilding, machinery kev lag luam thiab lwm yam, tshuav tsis tsuas yog rau nws zoo anti-corrosive kev ua tau zoo tshaj li zinc txheej, tab sis kuj rau nws cov nqi qis (lub tus nqi ntawm Al yog qis dua li ntawm Zn tam sim no). Lub ntiaj teb tsis tshua muaj xws li La tuaj yeem cuam tshuam qhov kev loj hlob thiab nce qhov adhesion, yog li lawv tau ua haujlwm los tiv thaiv cov hlau thiab lwm yam. metallic alloys tiv thaiv oxidation thiab corrosion. Txawm li cas los xij, tsuas muaj ob peb cov ntaub ntawv luam tawm ntawm daim ntawv thov La hauv kub dipped galvalume txheej, thiab nyob rau hauv daim ntawv no cov teebmeem ntawm La ntxiv rau corrosion kuj ntawm kub-dipped galvalume txheej tau tshawb xyuas.

Kev sim

[1] Kub-dipping

Kub-dipped Zn-Al-Si-La alloy coatings muaj 0,0.02wt.%, 0.05wt.%, 0.1wt.% thiab 0.2wt.% La tau thov rau Ф 1 hli me me steel hlau. Cov txheej txheem yog raws li nram no: ntxuav kom tshem tawm xeb thiab greasing los ntawm supersonic yoj (55 ° C) → ntxuav los ntawm dej → fluxing (85 ° C) → ziab (100 ~ 200 ° C) kub-dipping (640 ~ 670 ° C, 3-5 s., ib.).

[2] Kev ntsuas qhov hnyav

Kev ntsuas kev poob phaus yog ntsuas los ntawm tooj liab-accelerated acetic acid ntsev tsuag tshuaj ntsuam (CASS) thiab immersion corrosion tests nqa tawm nyob rau hauv ib tug ntsev tsuag chamber thiab 3.5% NaCl tov. Tom qab kev ntsuam xyuas, cov khoom corrosive raug tshem tawm los ntawm kev siv tshuab, yaug nrog dej ntws, tom qab ntawd qhuav los ntawm huab cua txias thiab qhov hnyav ntsuas los ntawm hluav taws xob ntsuas. Nyob rau hauv ob qho tib si, peb parallel cov qauv tau ua kom tau txais cov txiaj ntsig zoo dua. Lub sij hawm sim yog 120 h rau CASS xeem thiab 840 h rau kev sim rau immersion.

[3] Electrochemical xeem

Electrochemical xeem tau ua los ntawm IM6e electrochemical chaw ua hauj lwm muab los ntawm lub teb chaws Yelemees, noj platinum phaj raws li txee electrode, saturated calomel electrode raws li siv electrode, thiab kub-dipped Zn-Al-Si-La coatings me me hlau hlau ua hauj lwm electrode. Qhov nruab nrab corroding yog 3.5% NaCl tov. Qhov chaw ntawm qhov chaw raug rau cov tshuaj ntsuam xyuas yog 1cm2. Electrochemical impedance spectroscopy (EIS) kev ntsuas tau ua nrog qhov zaus ntawm 10 kHz mus txog 10 mHz, qhov dav ntawm qhov hluav taws xob sinusoidal voltage yog 10 mV (rms).Polarization curves tsis muaj zog tau sau tseg ntawm qhov voltage ntawm -70 mV. rau 70 mV, tus nqi scanning yog 1 mV / s. Hauv ob qho tib si, kev sim tsis tau pib kom txog thaum lub peev xwm corrosion tseem nyob ruaj khov (qhov kev hloov pauv tsawg dua 5 mV hauv 5 min).

[4] SEM and XRD studies

Surface morphologies ntawm cov qauv raug kuaj xyuas los ntawm SSX-550 scanning electron microscope (SEM) tom qab kev kuaj corrosion hauv cov ntsev tsuag chamber thiab 3.5% NaCl tov. Cov khoom siv corrosion tsim nyob rau saum npoo ntawm cov qauv hauv cov tshuaj tsuag ntsev thiab 3.5% NaCl tov tau sim siv PW-3040160 X-ray diffraction (XRD).

Cov txiaj ntsig thiab kev sib tham

[1] Corrosion kuj
[1.1] Poob poob
Fig.1 qhia txog cov txiaj ntsig ntawm kev ntsuas qhov hnyav hauv cov tshuaj ntsev ntsev thiab 3.5% NaCl tov. Tus nqi corrosion ntawm cov qauv hauv ob qho tib si tau txo qis ua ntej nrog nce La cov ntsiab lus mus txog 0.05wt.% thiab tom qab ntawd nce ntxiv nrog cov ntsiab lus La ntxiv. Yog li ntawd, qhov zoo tshaj plaws corrosion kuj tau ntsib nyob rau hauv cov coatings uas muaj 0.05wt.%La. Nws tau pom tias thaum lub sij hawm immersion test, cov xeb liab tau pom ntxov tshaj plaws ntawm 0wt.% La txheej txheej hauv 3.5% NaCl tov, txawm li cas los xij, kom txog rau thaum qhov kev sim immersion tas, tsis muaj xeb liab ntawm 0.05wt.% La txheej txheej. .

2.1.2 Kev xeem Electrochemical

Fig.2 qhia pom tsis muaj zog polarization nkhaus rau Zn-Al-Si-La alloy txheej hauv 3.5% NaCl tov. Nws tuaj yeem pom tau tias cov duab tsis muaj zog polarization curves pom qhov sib txawv ntawm ob peb, thiab cov txheej txheem corrosion ntawm txhua yam ntawm cov hlau coatings tau tswj los ntawm cathodic cov tshuaj tiv thaiv. Cov txiaj ntsig Tafel haum raws li qhov tsis muaj zog polarization curves hauv Fig.2 tau nthuav tawm hauv Table 1. Zoo ib yam li kev ntsuas qhov hnyav, nws kuj tau pom tias qhov corrosion kuj ntawm galvalume txheej tuaj yeem txhim kho los ntawm qhov sib ntxiv me me ntawm La thiab qhov tsawg kawg nkaus. corrosion tus nqi tau nrog 0.05wt.%La.

Fig.3 sawv cev ntawm Nyquist daim duab sau rau cov txheej txheem nrog ntau qhov sib txawv ntawm La ntxiv raug rau 3.5% NaCl tov rau 0.5 h. Nyob rau hauv txhua rooj plaub, muaj ob lub arcs uas txhais tau tias ob lub sij hawm tas mus li. Ib qho tshwm sim ntawm qhov muaj zaus sawv cev dielectric yam ntxwv ntawm cov hlau txheej, thaum lub sij hawm tsawg zaus sib raug rau cov hlau me me hauv qhov pores (piv txwv li Txheej tsis xws luag). Raws li La ntxiv nce, txoj kab uas hla ntawm lub siab zaus arc nce, cov nyhuv no tau tshaj tawm nyob rau hauv rooj plaub ntawm Zn55Al1.6Si0.05La alloy txheej. Txawm li cas los xij, nrog kev nce ntxiv ntawm La cov ntsiab lus, txawm li cas los xij, txoj kab uas hla ntawm qhov siab arc txo qis inversely. Lub caij no, qhov nruab nrab ntawm tag nrho cov arcs leaned mus rau plaub lub quadrant, qhia tias cov nyhuv dispersion tshwm sim nyob rau hauv lub electrode nto.Raws li cov mob no, cov txiaj ntsig zoo tuaj yeem tau txais los ntawm kev siv CPE (cov ntsiab lus tsis tu ncua) es tsis txhob muaj lub peev xwm ntshiab uas tau pom los ntawm lwm pab pawg tshawb fawb.