Passivation yog Cov txheej txheem ntawm passivation ntawm hlau txhais tau tias tsim cov yeeb yaj kiab nyias ntawm qhov chaw txhawm rau tiv thaiv corrosion

2024 Tus sau: Howard Calhoun | [email protected]. Kawg hloov kho: 2023-12-17 10:28

Txoj kev niaj hnub ntawm kev tiv thaiv cov hlau los ntawm corrosion yog tsawg thiab tsawg dua yuav ua tau raws li cov kev cai uas siv rau kev ua tau zoo ntawm cov qauv thiab cov khoom tseem ceeb. Beams nyob rau hauv lub tsev thav duab, cov kav dej thiab cov hlau claddings tsis tuaj yeem ua yam tsis muaj kev tiv thaiv xeb ib leeg thaum nws los txog rau kev siv cov khoom mus ntev. Ib txoj hauv kev zoo dua rau kev tiv thaiv corrosion yog txoj kev electrochemical thiab, tshwj xeeb, passivation. Qhov no yog ib txoj hauv kev los siv cov kev daws teeb meem uas tsim los tiv thaiv thiab insulating zaj duab xis rau ntawm qhov chaw ua haujlwm.

Technology overview

Passivation yuav tsum to taub raws li cov txheej txheem ntawm kev tsim cov yeeb yaj kiab nyias ntawm cov hlau, cov qauv uasyam ntxwv los ntawm kev ua haujlwm siab. Ntxiv mus, cov haujlwm ntawm cov txheej no tuaj yeem sib txawv - piv txwv li, hauv cov roj teeb electrolytes, nws tsis tsuas yog ua rau lub neej ntawm cov electrodes, tab sis kuj txo qhov kev siv ntawm tus kheej tawm. Los ntawm qhov pom ntawm kev tiv thaiv corrosion, passivation yog ib txoj hauv kev los ua kom muaj kev tiv thaiv ntawm cov khoom siv mus rau qhov chaw nruj heev uas provokes txoj kev loj hlob ntawm xeb. Tib lub cev ntawm kev tsim cov txheej txheem tiv thaiv-insulating tuaj yeem sib txawv. Kev siv hluav taws xob thiab tshuaj lom neeg yog qhov sib txawv, tab sis nyob rau hauv ob qho tib si, qhov kawg tshwm sim yuav yog kev hloov pauv ntawm cov qauv sab nraud ntawm lub workpiece mus rau lub xeev tsis muaj zog.

Txoj cai ntawm electrochemical tiv thaiv corrosion

Qhov tseem ceeb hauv electrochemical passivation yog qhov cuam tshuam ntawm sab nraud tam sim no ntawm lub hom phiaj nto. Thaum lub sij hawm dhau ntawm cov cathode tam sim no los ntawm corroding hlau qauv, nws muaj peev xwm hloov nyob rau hauv cov kev coj tsis zoo, uas kuj hloov qhov xwm ntawm cov txheej txheem ntawm ionization ntawm lub workpiece molecules. Nyob rau hauv tej yam kev mob ntawm anodic raug los ntawm ib sab ntawm ib tug sab nraud polarizer (ib txwm rau cov kua qaub media), yuav tsum tau nce nyob rau hauv tam sim no. Qhov no yog qhov tsim nyog los tua cov polarizer thiab tom qab ntawd ua tiav tag nrho kev tiv thaiv corrosion. Txawm li cas los xij, nrog nce passivation ntawm qhov chaw vim yog sab nraud tam sim no, kev tso tawm ntawm hydrogen nce, uas ua rau hydrogenation ntawm cov hlau. Yog li ntawd, cov txheej txheem ntawm hydrogen dissolution nyob rau hauv cov hlau qauv pib, ua raws li los ntawm ib tug deterioration nyob rau hauv lub cev khoom ntawm lub workpiece.

Cathodetxoj kev tiv thaiv

Qhov no yog ib hom hluav taws xob hluav taws xob tiv thaiv corrosion uas siv cov txheej txheem ntawm kev siv cathodic tam sim no. Tab sis txoj kev no tuaj yeem siv tau ntau txoj hauv kev. Piv txwv li, qee zaum hauv kev tsim khoom, kev hloov pauv muaj peev xwm txaus yog muab los ntawm kev txuas ib feem mus rau qhov chaw sab nraud tam sim no raws li cathode. Lub anode yog ib qho inert auxiliary electrode. Txoj kev no ua rau kev hla ntawm cov seams tom qab vuam, tiv thaiv hlau platforms ntawm cov qauv drilling thiab cov kav dej hauv av. Qhov zoo ntawm cov txheej txheem cathodic passivation muaj xws li kev ua haujlwm hauv kev tiv thaiv ntau yam txheej txheem corrosion.

Ntxiv rau qhov kev puas tsuaj dav dav, pitting thiab intergranular corrosion yog tiv thaiv. Xws li cov txheej txheem ntawm cathodic electrochemical kev ua raws li kev tiv thaiv thiab galvanic kuj tau xyaum. Lub ntsiab feature ntawm cov txheej txheem no yog siv cov hlau electronegative ntau dua li polarizer. Cov khoom no yog nyob rau hauv kev sib cuag nrog cov khoom tiv thaiv thiab ua raws li anode, raug rhuav tshem thaum lub sijhawm ua haujlwm. Cov kev zoo sib xws feem ntau yog siv thaum insulating cov qauv me me, qhov chaw ntawm cov tsev thiab cov qauv.

Anode tiv thaiv txoj kev

Nrog anodic rwb thaiv tsev ntawm cov hlau qhov chaw, lub peev xwm hloov mus rau hauv kev coj zoo, uas tseem ua rau muaj kev tiv thaiv ntawm qhov chaw rau cov txheej txheem corrosion. Ib feem ntawm lub zog ntawm cov ntawv thov anode tam sim no yog siv rau ntawm ionization ntawm hlaumolecules, thiab lwm qhov - txhawm rau txhawm rau cov tshuaj tiv thaiv cathodic.

Ntawm cov yam tsis zoo ntawm txoj hauv kev no yog qhov siab ntawm kev tawg ntawm cov hlau, uas yog qhov sib piv nrog tus nqi txo cov tshuaj tiv thaiv corrosion. Ntawm qhov tod tes, ntau yuav nyob ntawm cov hlau uas siv passivation. Cov no tuaj yeem yog ob qho tib si nquag yaj cov ntaub ntawv thiab qhov chaw nrog cov txheej txheem hluav taws xob tsis tiav, cov qauv uas nyob rau hauv lub xeev passive kuj muaj txiaj ntsig rau kev sib tsoo thiab kev puas tsuaj. Tab sis nyob rau hauv txhua rooj plaub, kom ua tiav cov txiaj ntsig tseem ceeb ntawm kev tiv thaiv kev tiv thaiv corrosion, kev siv cov anode loj tam sim no yuav tsum tau.

Los ntawm qhov kev xav no, txoj kev no tsis raug pom zoo los siv rau kev saib xyuas lub sijhawm luv ntawm cov rwb thaiv tsev, txawm li cas los xij, tus nqi qis zog rau kev tswj xyuas cov superimposed tam sim no tag nrho ua rau anodic passivation. Los ntawm txoj kev, tsim kev tiv thaiv yav tom ntej yuav tsum muaj lub zog tam sim no tsuas yog 10-3 A / m 2.

Kev siv tshuaj tua kab mob

Ib txoj hauv kev siv thev naus laus zis los ua kom cov hlau tsis muaj zog thaum ua haujlwm hauv qhov chaw nruj heev. Inhibitors muab tshuaj lom neeg passivation, uas txo qhov kev siv ntawm kev sib cais ntawm cov hlau thiab, mus rau qhov sib txawv degrees, tshem tawm cov teeb meem ntawm corrosion puas.

Nyob rau hauv nws tus kheej, tus inhibitor yog, nyob rau hauv lub siab, ib qho analogue ntawm superimposed tam sim no, tab sis nrog ib tug tshuaj los yog electrochemical ua ke ua ke. Organic thiab inorganic tshuaj ua cov activators ntawm kev tiv thaiv zaj duab xis, thiab ntau zaus -tshwj xeeb xaiv cov tebchaw complex. Kev taw qhia ntawm tus inhibitor mus rau hauv ib qho kev txhoj puab heev ua rau muaj kev hloov pauv hauv cov qauv ntawm cov hlau nto, cuam tshuam rau kinetic electrode cov tshuaj tiv thaiv.

Kev tiv thaiv zoo yuav nyob ntawm seb hom hlau, cov xwm txheej sab nraud thiab lub sijhawm ntawm tag nrho cov txheej txheem. Yog li ntawd, nyob rau hauv lub sij hawm ntev, lub passivation ntawm stainless hlau yuav xav tau ntau lub zog kev pab cuam los tiv thaiv ib tug aggression ib puag ncig dua nyob rau hauv cov ntaub ntawv ntawm tooj dag los yog hlau. Tab sis cov txheej txheem ntawm kev ua ntawm inhibitor nws tus kheej tseem yuav ua lub luag haujlwm tseem ceeb.

Inhibitors-passivators

Kev tiv thaiv corrosion raws li cov hauv paus ntsiab lus ntawm kev tsim cov kev ua haujlwm tsis zoo tuaj yeem tsim los ntawm cov inhibitors sib txawv. Yog li, adsorption tebchaw nyob rau hauv daim ntawv ntawm anions, cations, thiab nruab nrab molecules yog dav siv, uas yuav muaj ib tug tshuaj thiab electrostatic nyhuv ntawm ib tug hlau nto. Cov no yog universal txhais tau tias ntawm kev tiv thaiv corrosion, tab sis lawv cov nyhuv yog txo nyob rau hauv ib puag ncig uas oxygen polarization dominates. Piv txwv li, ib qho tshwj xeeb inhibitor nrog oxidizing zog yuav tsum tau siv los passivate stainless hlau. Cov no muaj xws li molybdates, nitrites, thiab chromates, uas tsim cov oxide zaj duab xis nrog ib tug zoo polarization hloov txaus kom tso pa oxygen molecules. Nyob rau saum npoo ntawm cov hlau, chemisorption ntawm lub resulting oxygen atoms tshwm sim, thaiv cov feem ntau active cheeb tsam ntawm txheej thiab tsim ib tug ntxiv muaj peev xwm ua rau kom qeeb lub dissolution cov tshuaj tiv thaiv ntawm cov hlau qauv.

Kev siv passivation hauv kev tiv thaiv ntawm semiconductors

Kev ua haujlwm ntawm cov khoom siv hluav taws xob hauv qab hluav taws xob siab yuav tsum muaj txoj hauv kev tshwj xeeb rau kev tiv thaiv corrosion. Nyob rau hauv cov ntaub ntawv no, lub passivation ntawm cov hlau yog qhia nyob rau hauv lub voj kev cais ntawm lub active cheeb tsam ntawm ib feem. Kev tiv thaiv hluav taws xob ntug yog tsim los ntawm diodes thiab bipolar transistors. Planar passivation cuam tshuam nrog kev tsim lub nplhaib tiv thaiv, nrog rau txheej txheej crystalline nrog iav. Lwm txoj hauv kev ntawm mesa passivation suav nrog kev tsim cov zawj txhawm rau txhawm rau txhawm rau nce qib siab tshaj plaws uas tso cai rau kev ntxhov siab ntawm qhov chaw ntawm cov qauv hlau siv lead ua.

Kev hloov kho cov yeeb yaj kiab tiv thaiv corrosion

Cov txheej txheem tsim los ntawm kev tso cai tso cai rau ntau yam ntxiv. Qhov no tuaj yeem yog plating, chrome plating, tha xim thiab tsim cov yeeb yaj kiab kev txuag. Cov txheej txheem ntawm kev pabcuam ntxiv dag zog tiv thaiv kev tiv thaiv corrosion zoo li no kuj tau siv. Rau zinc txheej, cov kev daws teeb meem tshwj xeeb yog tsim los ntawm cov khoom siv polymer thiab chromium. Rau ib lub hnab ntim galvanized li niaj zaus, siv cov dej yaug uas tsis yog reactive additives.

Zaj lus

Corrosion yog txheej txheem kev puas tsuaj uas tuaj yeem tshwm sim nws tus kheej hauv ntau txoj kev, tab sis nyob rau hauv txhua rooj plaub nws ua rau muaj kev puas tsuaj ntawm qee yam kev ua haujlwm ntawm cov hlau. Nws yog ib qho ua tau kom tshem tawm qhov tshwm sim ntawm cov txheej txheem zoo li no hauv ntau txoj hauv kev, nrog rau kev siv cov hlau tsis zoo, uas yog tus cwj pwm los ntawm qhov pib txo qis.xeb rhiab heev. Txawm li cas los xij, vim qee qhov laj thawj nyiaj txiag thiab thev naus laus zis, kev siv cov txheej txheem tiv thaiv corrosion los yog siv cov hlau uas muaj kev tiv thaiv corrosion siab tsis yog ib txwm ua tau.

Qhov kev daws teeb meem zoo tshaj plaws hauv cov xwm txheej zoo li no yog passivation - nws yog ib qho pheej yig thiab siv tau zoo ntawm kev tiv thaiv hlau ntawm ntau hom. Raws li qee qhov kev suav, ib lub tshuab hluav taws xob nrog cov khoom siv hluav taws xob xaiv tau zoo tuaj yeem tiv thaiv corrosion ntawm 8-kilometer underground pipeline kab. Raws li qhov tsis zoo, lawv tau hais nyob rau hauv kev nyuaj ntawm kev siv electrochemical passivation txoj hauv kev.