Ntu 1: Ib puag ncig muaj kev cuam tshuam rau tooj liab Oxidation & Corrosion
1. Humid & High - Ib puag ncig Sulfur
Tej yam xwm txheej: Cov chaw lag luam (smelters, fais fab nroj tsuag), thaj chaw ntug dej hiav txwv uas muaj cov sulfur dioxide siab (SO₂), cov chaw kho dej khib nyiab, thiab cov chaw sab hauv tsev uas muaj cua tsis zoo (xws li hauv qab daus, chav ua noj).
Corrosion Mechanism: Sulfur dioxide reacts nrog ya raws thiab tooj liab rau daim ntawvtooj liab sulfide (CuS)- zaj duab xis dub, ntxeem tau uas tsis tiv thaiv lub hauv paus hlau (tsis zoo li qhov ruaj khov ntsuab patina ntawm tooj liab carbonate). Qhov no ua rau oxidation tsis tu ncua thiab decoloration nto.
Piv txwv: Tooj tooj hluav taws xob nyob hauv thaj chaw muaj kev lag luam feem ntau tsim cov tarnish dub nyob rau hauv 6-12 lub hlis, txo cov conductivity raws sij hawm.
2. Dej ntsev & Marine ib puag ncig
Tej yam xwm txheej: Seawater immersion (nkoj hulls, offshore platforms), ntug dej hiav txwv cua (tsim tshuaj tsuag), thiab dej brackish daim ntaub ntawv (estuaries, coastal txias tshuab).
Corrosion Mechanism: Cov tshuaj chloride siab (Cl⁻) concentration ua rau cov tooj liab oxide zaj duab xis, ua raupitting corrosionthiab (rau tooj dag alloys)dezincification(xaiv leaching ntawm zinc, tawm hauv nkig tooj liab matrix).
Cov ntaub ntawv siv: Copper corrosion tus nqi hauv dej hiav txwv nce mus txog 0.1-0.3 hli / xyoo, thaum tooj dag tuaj yeem corrode ntawm 0.8-1.2 hli / xyoo (ASTM G111 cov qauv xeem).
3. Acid & Alkaline Ib puag ncig
Cov xwm txheej Acid: Mining sites (acid mine drainage), chemical processing plant (sulfuric acid, hydrochloric acid), thiab acidic rain- regions prone.
Mechanism: Cov kua qaub muaj zog yaj cov oxide zaj duab xis thiab hnov mob ncaj qha nrog tooj liab, tsim cov ntsev tooj liab soluble (xws li CuSO₄, CuCl₂) uas ua rau corrosion.
Cov xwm txheej Alkaline: Caustic soda (NaOH) cov chaw tsim khoom, cov qauv ua vaj tse (pH siab los ntawm cov cement hydration), thiab cov txheej txheem ua haujlwm tu.
Mechanism: Concentrated alkalis (pH > 12) ua rauKev ntxhov siab corrosion cracking (SCC)nyob rau hauv txias - ua hauj lwm tooj liab alloys (piv txwv li, H24 temper tooj dag), tshwj xeeb tshaj yog nyob rau hauv tensile stress.
4. Electrolytic Corrosion (Galvanic Corrosion)
Tej yam xwm txheej: Copper Cheebtsam nyob rau hauv kev sib cuag nrog cov hlau tsis sib xws (xws li steel, aluminium, zinc) nyob rau hauv lub xub ntiag ntawm noo noo los yog electrolytes (xws li, tooj liab kav txuas nrog steel fittings, tooj dag fasteners ntawm txhuas lug).
Corrosion Mechanism: Copper yog cov hlau cathodic (siab electrode muaj peev xwm), thaum hlau / aluminium yog anodic. Qhov no tsim cov galvanic cell, ua rau cov hlau anodic corrode sai thiab ceev tooj liab oxidation raws li cathode.
Lus Cim: Galvanic corrosion yog 5-10 lub sij hawm sai dua li niaj hnub corrosion, feem ntau ua rau tsis ua hauj lwm ntxov ntawm cov khoom sib dhos.
5. Siab -Tsub & Oxidizing Ib puag ncig
Tej yam xwm txheej: Rauv, kub exchangers, boiler raj, thiab aerospace Cheebtsam ua hauj lwm ntawm 200-500 degree.
Corrosion Mechanism: Ua kom kub ceev ceev tsim ntawmtooj liab oxide (CuO / Cu₂O). Ntawm qhov kub siab tshaj 300 degree, oxide zaj duab xis yuav ntxeem tau thiab nquag mus rau spallation, exposing tshiab tooj liab mus ntxiv oxidation.
Piv txwv: Copper heat exchanger tubes nyob rau hauv boilers tej zaum yuav tsim tuab, flaky oxide txheej nyob rau hauv 1-2 xyoo, txo tshav kub efficiency.
Ntu 2: Kev Tiv Thaiv Kev Tiv Thaiv rau Copper & Copper Alloys
1. Txheej Txheej & Platings
a. Kev kho mob Passivation
Txheej txheem: Muab cov tooj liab tso rau hauv cov tshuaj tov tshuaj (piv txwv li, chromic acid, phosphoric acid, los yog benzotriazole / BTA) los tsim ib daim duab ntom ntom, ruaj khov rau ntawm qhov chaw.
Qhov zoo: Txhim kho lub ntuj oxide txheej ntawm corrosion tsis kam hloov lub hauv paus hlau cov khoom. BTA-raws li passivation yog dav siv rau cov khoom siv hluav taws xob thiab khoom noj khoom haus-kev tiv tauj daim ntawv thov (FDA-ua raws).
Daim ntawv thov: Copper xov hlau, connectors, thiab kav dej fixtures.
b. Hlau Platings
Cov Platings: Nickel (Ni), tin (Sn), chrome (Cr), thiab kub (Au) rau siab - daim ntawv thov precision.
Nickel plating: Muab kev hnav zoo heev thiab corrosion kuj; zoo tagnrho rau marine hardware (piv txwv li, tooj dag li qub) thiab muaj machinery qhov chaw.
Tin Plating: Txhim kho solderability thiab tiv thaiv tarnish; siv rau hluav taws xob terminals thiab connectors.
Standard Reference: Ua raws li ASTM B456 (nickel plating) thiab ASTM B545 (tin plating) rau kev tswj kom zoo.
c. Organic Txheej
Kev xaiv: Epoxy xim, polyurethane coatings, thiab lacquers.
Qhov zoo: Nqi -zoo, yooj yim rau kev thov, thiab muaj nyob rau hauv ntau yam xim. Epoxy txheej tiv taus cov kua qaub, alkalis, thiab dej ntsev, ua rau lawv haum rau cov qauv sab nraum zoov (xws li, tooj liab vov tsev, marine railings).
Daim ntawv thov: Ua kom huv si kom zoo (degreasing, abrading) ua ntej txheej los xyuas kom meej adhesion.
2. Kev xaiv Alloy & Cov khoom siv kom zoo
Corrosion{0}}Resistant Alloys: Hloov cov tooj liab dawb lossis tooj dag nrog siab -kev ua tau zoo alloys rau ib puag ncig hnyav:
Aluminium Bronze (C63000): Resistant seawater corrosion thiab biofouling; siv rau nkoj propellers thiab offshore Cheebtsam.
Tooj liab -Nickel (C71500): Zoo heev tiv thaiv dej ntsev thiab acidic tej yam kev mob; zoo tagnrho rau tshav kub exchanger raj thiab ntug hiav txwv piping.
Phosphor Bronze (C51000): Muaj phosphorus los txhim kho hnav thiab corrosion kuj; siv rau springs thiab hluav taws xob tiv tauj nyob rau hauv industrial ib puag ncig.
Zam tsis haum Alloys: Tsis txhob siv tooj dag (C26000, C28000) hauv dej hiav txwv los yog acidic ib puag ncig vim muaj kev pheej hmoo dezincification.
3. Environmental Control & Isolation
Cov dej noo tsawg: Txhim kho qhov cua hauv qhov chaw sab hauv tsev (xws li, siv cov dehumidifiers) kom cov av noo qis dua 60%. Rau cov khoom uas nyob ib puag ncig (xws li, hluav taws xob enclosures), siv desiccants los nqus dej noo.
Kev tshem tawm cov tshuaj lom neeg: Txhim kho cov lim cua hauv thaj chaw muaj kev lag luam kom txo cov sulfur dioxide thiab cov khoom me me. Rau cov tshuab dej, siv cov tshuaj inhibitors (xws li sodium nitrite, BTA) los tiv thaiv corrosion.
Galvanic cais:
Siv cov khoom uas tsis yog{0}}cov khoom siv hluav taws xob (piv txwv li, roj hmab, yas) ntawm cov tooj liab thiab cov hlau tsis sib xws los rhuav tshem cov galvanic cell.
Siv cov tshuaj tiv thaiv corrosion{0}} tiv thaiv txheej rau cov hlau anodic (piv txwv li, steel) los tiv thaiv kev hloov ion.
Ua raws li cov galvanic series thaum tsim cov rooj sib txoos: zam kev sib koom ua ke ntawm anodic (aluminium) thiab cathodic (tooj liab) hlau.
4. Kev tiv thaiv Cathodic
Siv tau Scenarios: Loj - cov qauv (piv txwv li, cov kav dej tooj liab, nkoj hulls, offshore platforms) hauv dej hiav txwv lossis av.
Cov txheej txheem:
Kev Txhaum Cai Anodes: Txuas zinc lossis aluminium anodes rau cov qauv tooj liab. Cov anodes corrode preferentially, tiv thaiv cov tooj liab cathode.
Impressed Current Cathodic Protection (ICCP): Siv ib qho me me sab nraud tam sim no rau cov qauv, ua rau nws muaj cathode thiab inhibiting corrosion.
Txuj kev ua raws cai: Raws li NACE SP0169 rau kev siv sab nrauv thiab ASTM G95 rau cathodic tiv thaiv tsim.
5. Kev tu ncua & Kev tshuaj xyuas
Ntxuav: Tshem tawm cov kab mob ntawm qhov chaw (plua plav, ntsev, roj) nrog cov tshuaj ntxuav tes thiab cov ntaub mos muag. Tsis txhob siv cov tshuaj abrasive uas khawb cov oxide zaj duab xis.
Kev tshuaj xyuas: Ua cov kev kuaj xyuas raws sij hawm (kev tshuaj xyuas qhov muag, kuaj ultrasonic) kom pom cov cim ntxov ntawm corrosion (xws li pitting, discoloration). Rau cov khoom tseem ceeb (piv txwv li, cov hlab ntsha siab), teem caij kuaj xyuas corrosion txhua xyoo.
Kov -Kev Kho Kom Zoo: Tam sim ntawd kho cov coatings puas los yog platings los tiv thaiv ib cheeb tsam corrosion.
