Corrosion ntawm aluminium thiab nws cov alloys. Cov txheej txheem rau kev sib ntaus sib tua thiab tiv thaiv aluminium los ntawm corrosion

2024 Tus sau: Howard Calhoun | [email protected]. Kawg hloov kho: 2024-01-02 13:55

Txawm hais tias txhuas yog cov hlau tsis muaj hlau thiab, piv rau cov hlau zoo tib yam, kuj tseem kim, nws yog siv los ntawm tib neeg. Cov khoom siv ruaj khov thiab lub teeb yuag no tuaj yeem siv tau hauv lub neej txhua hnub, kev tsim kho, thiab kev tsim khoom. Cov tshuaj formula ntawm txhuas nyob rau hauv lub periodic rooj zoo li no: Al.

Ib puas yog corroded

Rusts aluminium, raws li koj paub, qeeb heev. Tsawg kawg, hlau thiab hlau tsis tuaj yeem piv nrog nws hauv qhov no. Kev tiv thaiv ntawm aluminium rau corrosion yog piav qhia feem ntau los ntawm qhov tseeb tias, nyob rau hauv ib txwm muaj xwm txheej, nyias oxide tiv thaiv zaj duab xis ua rau ntawm nws qhov chaw. Raws li qhov tshwm sim, cov tshuaj ua haujlwm ntawm aluminium yog txo qis.

Yam cuam tshuam rau xeb tiv thaiv

Aluminium tiv taus corrosion, tab sis qee zaum nws tseem tuaj yeem pib tawg sai heev vim oxidation. Qhov no feem ntau tshwm sim thaum cov yeeb yaj kiab puas vim qee yam lossis tsis tuaj yeem tsim nws.

Feem ntau, txhuas poob nws qhov kev tiv thaiv sab nraud los ntawm cov kua qaublos yog alkalis. Kev puas tsuaj ib puag ncig kuj tuaj yeem ua rau kev puas tsuaj ntawm zaj duab xis.

Type of corrosion

Tom qab kev puas tsuaj ntawm zaj duab xis, Al thiab nws cov alloys pib xeb, uas yog, nws tus kheej puas, zoo li ntau lwm yam hlau. Qhov no tuaj yeem nthuav tawm aluminium thiab corrosion:

1. tshuaj. Hauv qhov no, rusting tshwm sim nyob rau hauv ib puag ncig gaseous yam tsis muaj dej. Nyob rau hauv cov ntaub ntawv no, lub nto ntawm txhuas cov khoom raug puas tsuaj nyob ib ncig ntawm tag nrho cov cheeb tsam.
2. Electrochemical. Corrosion ntawm txhuas nyob rau hauv cov ntaub ntawv no tshwm sim nyob rau hauv ib tug ntub ib puag ncig.
3. Gas. Hom kev xeb no tshwm sim thaum txhuas nyob rau hauv kev sib cuag ncaj qha nrog qee cov tshuaj lom neeg.

Qhov sib npaug rau aluminium corrosion (oxygen oxidation) hauv huab cua yog raws li nram no: 4AI + 3O ₂=2AL₂O3_.

Cov tshuaj formula ntawm cov tshuaj tiv thaiv oxide yog AL₂O_3.

Alloys

Cov tshuaj tiv thaiv corrosion feem ntau yog cov khoom siv txhuas. Ntawd yog, yuav luag 90% hlau. Hmoov tsis zoo, aluminium alloys muaj ntau yam ua rau xeb. Nws ntseeg tau tias magnesium impurities txo cov corrosion kuj ntawm cov hlau no tsawg kawg nkaus, thiab tooj liab impurities feem ntau ntawm tag nrho cov.

Mg-Al alloys

Cov ntaub ntawv zoo li no tau siv dav hauv kev tsim kho, khoom noj khoom haus thiab tshuaj lom neeg kev lag luam. Lawv kuj tau siv ntau heev hauv mechanical engineering. Nws ntseeg tau tias cov ntaub ntawv zoo li no tau zoo rau kev tsim cov qauv,raug dej hiav txwv.

Nyob rau hauv cov xwm txheej uas magnesium tsis ntau tshaj 3% nyob rau hauv muaj pes tsawg leeg ntawm cov alloy, nws yuav muaj yuav luag tib yam anti-corrosion zog li technical aluminium. Magnesium nyob rau hauv xws li ib tug alloy yog nyob rau hauv cov khoom tov thiab nyob rau hauv daim ntawv ntawm Al8Mg5 particles uniformly faib thoob plaws hauv lub matrix.

Yog tias cov hlau muaj ntau dua 3% ntawm cov hlau no, Al8Mg5 cov khoom pib poob tawm, feem ntau, tsis yog hauv cov nplej, tab sis raws li lawv cov ciam teb. Thiab qhov no, nyob rau hauv lem, muaj ib tug tsis tshua muaj tshwm sim nyob rau hauv lub anti-corrosion zog ntawm cov khoom. Ntawd yog, cov khoom lag luam dhau los ua tsis tshua muaj zog rau xeb.

YMagnesium thiab silicon alloys

Cov ntaub ntawv no feem ntau yog siv hauv engineering thiab kev tsim kho. Mg2Si ua alloys ntawm no ntau yam muaj zog heev. Qee zaum tooj liab kuj yog ib feem ntawm cov khoom zoo li no. Nws kuj tau nkag mus rau hauv cov alloy rau hardening. Txawm li cas los xij, tooj liab tau ntxiv rau cov khoom siv hauv cov khoom me me. Txwv tsis pub, cov khoom tiv thaiv corrosion ntawm aluminium alloy yuav raug txo kom tsawg. Intercrystalline rusting nyob rau hauv lawv pib twb nrog qhov sib ntxiv ntawm ntau tshaj 0.5% tooj liab.

Tsis tas li, qhov cuam tshuam rau corrosion ntawm cov ntaub ntawv zoo li no tuaj yeem nce ntxiv nrog qhov tsis ncaj ncees nce ntawm cov nyiaj silicon suav nrog hauv lawv cov muaj pes tsawg leeg. Cov tshuaj no yog ntxiv rau txhuas alloys, feem ntau nyob rau hauv xws li proportions uas tom qab tsim ntawm Mg2Si tsis muaj dab tsi nyob. Silicon hauv nws daim ntawv ntshiab tsuas muaj qee cov ntaub ntawv ntawm no ntau yam.

Corrosion ntawm aluminium thiabnws cov zinc alloys

Al xeb, raws li twb tau hais lawm, qeeb dua nws cov alloys. Qhov no kuj siv rau cov ntaub ntawv ntawm pawg Al-Zn. Xws li cov alloys yog qhov xav tau zoo, piv txwv li, hauv kev lag luam dav hlau. Qee hom yuav muaj tooj liab, lwm tus yuav tsis muaj. Nyob rau hauv rooj plaub no, thawj hom alloys, ntawm chav kawm, yog ntau resistant rau corrosion. Hauv qhov no, cov ntaub ntawv Al-Zn piv rau magnesium-aluminium.

Alloys ntawm no ntau yam nrog ntxiv ntawm tooj liab qhia cov cim ntawm ib co instability rau xeb. Tab sis tib lub sijhawm, lawv raug rhuav tshem vim kev xeb, lawv tseem qeeb dua cov uas tau siv magnesium thiab Cu.

Txoj kev yooj yim los daws cov xeb

Tau kawg, tus nqi ntawm corrosion ntawm aluminium thiab nws cov alloys kuj tuaj yeem txo qis. Tsuas muaj ob peb txoj hauv kev los tiv thaiv cov ntaub ntawv no los ntawm xeb.

Piv txwv li, nws muaj peev xwm tshem tawm qhov kev sib cuag ntawm cov hlau no thiab nws cov alloys nrog ib puag ncig los ntawm kev pleev xim rau cov ntaub ntawv pleev xim. Tsis tas li, txoj kev siv hluav taws xob feem ntau siv los tiv thaiv txhuas los ntawm xeb. Nyob rau hauv cov ntaub ntawv no, cov khoom yog ntxiv them nrog ib txheej ntawm ntau active hlau.

Lwm txoj hauv kev los tiv thaiv Al ntawm xeb yog qhov hluav taws xob oxidation. Cov txheej txheem hmoov txheej kuj tuaj yeem siv los tiv thaiv corrosion ntawm txhuas. Siv los tiv thaiv nws, tau kawg, thiab xeb inhibitors.

Yuav ua li cas oxidation ua tiav

Siv cov txheej txheem no, txhuas thiab nws cov alloys feem ntau tiv thaiv corrosion. Uaoxidation nyob rau hauv ib tug voltage ntawm 250 V. Siv cov txheej txheem no, ib tug muaj zog oxide zaj duab xis yog tsim rau saum npoo ntawm ib tug hlau los yog nws alloy.

Kev cuam tshuam ntawm cov khoom siv los ntawm qhov tam sim no yog ua los ntawm kev siv dej txias. Thaum tsis tshua muaj kub, vim muaj kev ntxhov siab, ib zaj duab xis ntawm qhov chaw ntawm aluminium yog tsim muaj zog heev thiab ntom. Yog tias cov txheej txheem ua tiav ntawm qhov kub thiab txias, nws hloov tawm kom xoob heev. Aluminium ua tiav nyob rau hauv ib puag ncig zoo li no xav tau kev tiv thaiv ntxiv los ntawm kev sib cuag nrog huab cua (pas duab).

Thaum siv cov thev naus laus zis no, cov khoom lag luam yog thawj zaug degreased hauv cov tshuaj oxalic acid. Tom qab ntawd cov aluminium los yog alloy yog dipped rau hauv alkali. Tom ntej no, cov hlau raug cuam tshuam los ntawm tam sim no. Nyob rau theem kawg, yog tias cov oxidation tau ua tiav ntawm qhov kub txaus, cov khoom siv ntxiv yog dyed los ntawm immersion hauv ntsev tov, thiab tom qab ntawd kho nrog chav.

Siv LMB

Txoj kev no, zoo li oxidation, yog siv los tiv thaiv txhuas los ntawm xeb ntau zaus. Cov khoom zoo li no tuaj yeem pleev xim los ntawm txoj kev qhuav, ntub lossis hmoov. Nyob rau hauv thawj rooj plaub, txhuas yog thawj zaug kho nrog ib tug muaj pes tsawg leeg uas muaj zinc thiab strontium. Tsis tas li ntawd, LKM nws tus kheej yog siv rau cov hlau.

Thaum siv cov hmoov txheej, qhov chaw ua haujlwm yog pre-degreased los ntawm immersion nyob rau hauv alkaline los yog acid daws. Ntxiv mus, chromate, zirconium, phosphate los yog titanium compounds yog siv rau cov khoom.

Sivinsulators

Ntau zaus, lwm cov hlau ua stimulants rau qhov pib ntawm corrosion txheej txheem hauv txhuas thiab nws cov alloys. Qhov no feem ntau tshwm sim nrog kev sib cuag ncaj qha ntawm cov khoom lossis lawv qhov chaw. Txhawm rau tiv thaiv aluminium los ntawm xeb, cov insulators tshwj xeeb yog siv rau qhov no. Xws li gaskets tuaj yeem ua los ntawm roj hmab, paronite, bitumen. Tsis tas li ntawd, cov kua roj vanish thiab xim tuaj yeem siv tau. Lwm txoj hauv kev los tiv thaiv aluminium los ntawm corrosion nyob rau hauv kev sib cuag nrog lwm cov ntaub ntawv yog lub tsho tiv no nrog cadmium.

Nws yog ib qho tseem ceeb tshwj xeeb los xyuas kom meej tias txhuas qhov chaw nyob rau hauv ntau yam mechanisms thiab cov rooj sib txoos yog insulated los ntawm kev sib cuag ncaj qha nrog tooj liab. Nws tseem ntseeg tau tias tsis yog tsuas yog cov khoom ua los ntawm Al yuav tsum tau tiv thaiv los ntawm kev sib cuag nrog lwm cov hlau. Nyob rau hauv cov nqe lus ntawm corrosion kuj, hlau yog ntau inferior rau txhuas, zoo li steel, piv txwv li. Yog li ntawd, xws li hlau thiab ib co lwm yam yog feem ntau tiv thaiv nyob rau hauv ib tug tshwj xeeb txoj kev. Cov ntaub ntawv tsuas yog them nrog ib txheej tiv thaiv aluminium. Tau kawg, cov khoom zoo li no kuj yuav tsum tau tiv thaiv los ntawm kev sib cuag nrog tooj liab lossis lwm yam hlau.