1.Dab tsi yog qhov corrosion kuj ntawm passivation txheej ntawm galvanized coils?
Lub luag haujlwm tseem ceeb ntawm txheej txheej passivation yog los tiv thaiv cov galvanized kauj los ntawm maj mam oxidizing nyob rau hauv cov huab cua thiab tsim "dawb xeb" (cov zinc carbonate hauv paus), es tsis txhob tiv thaiv corrosion los ntawm cov tshuaj corrosive heev. Nws txoj kev tiv thaiv tsom ntau dua nyob rau hauv atmospheric ib puag ncig es tsis yog tshuaj lom neeg nruab nrab ib puag ncig.
2.Dab tsi yog qhov kam rau alkali?
Tsis muaj zog alkaline ib puag ncig (piv txwv li, pH=8-11):
Ua tau zoo heev. Zinc ua cov zincates soluble nyob rau hauv ib puag ncig alkaline, tab sis ib qho tsis zoo ntawm cov yeeb yaj kiab (tshwj xeeb tshaj yog cov yeeb yaj kiab chromate passive) tuaj yeem muab qee qhov teeb meem, ncua qhov pib ntawm corrosion.
Txawm li cas los xij, thov nco ntsoov: lub sijhawm ntev los yog qhov siab siab yuav maj mam yaj thiab rhuav tshem ob qho tib si cov yeeb yaj kiab thiab cov zinc txheej.
Muaj zog alkaline ib puag ncig (piv txwv li, pH > 12):
Ua haujlwm tsis zoo. Muaj zog alkalis sai sai rhuav tshem cov txheej txheem passive thiab hnov mob hnyav nrog zinc los tsim sodium zincate soluble thiab tso tawm hydrogen, ua rau corrosion sai ntawm zinc txheej.
Xaus: Galvanized qhov chaw tsis haum rau siv nyob rau hauv qhov chaw muaj zog alkaline (xws li cov tshuaj sodium hydroxide concentrated).
3.Dab tsi yog acid kam rau ua?
Tsis muaj zog acid ib puag ncig (piv txwv li, pH=5-7):
Lawv muaj qee qhov kev tiv thaiv, xws li kev tiv thaiv zoo tiv thaiv dej nag (uas yog me ntsis acidic).
Txawm li cas los xij, txawm tias tsis muaj zog acids, yog tias tsis tu ncua, yuav maj mam degrade cov zaj duab xis passive thiab zinc txheej.
Muaj zog acid ib puag ncig (piv txwv li, pH <3):
Lawv muab kev tiv thaiv tsis zoo. Txhua yam ntawm cov yeeb yaj kiab passive yog yaj sai sai los ntawm cov kua qaub uas muaj zog. Cov kua qaub ces reacts ncaj qha nrog zinc, tsim zinc ntsev thiab tso hydrogen gas, uas ua rau corrosion sai heev.
Xaus: Galvanized qhov chaw yog qhov tsis tsim nyog rau kev siv nyob rau hauv qhov chaw muaj zog acid (xws li hydrochloric acid thiab sulfuric acid).
4.Dab tsi yog qhov txawv ntawm cov kua qaub thiab alkali tsis kam ntawm ntau hom passivation?
Chromate passivation txheej (ib txwm, kev ua tau zoo tshaj plaws tab sis tsis tshua muaj kev phooj ywg ib puag ncig)
Nws muab kev tiv thaiv los ntawm kev sib xyaw ua ke ntawm "kev tiv thaiv lub cev" thiab "tshuaj lom neeg tus kheej- kho." Thaum ntsib me me pitting corrosion, soluble hexavalent chromium hauv zaj duab xis tuaj yeem txav mus rau qhov chaw puas, tsim cov yeeb yaj kiab tiv thaiv tshiab.
Ntawm peb hom passivation, nws muaj qhov muaj zog tiv thaiv tsis muaj zog acids thiab alkalis, tab sis tseem muaj zog rau cov acids thiab alkalis.
Chromium{0}}dawb passivation txheej (ntau lub ntsiab, tus phooj ywg ib puag ncig)
Cov khoom tseem ceeb yog oxides lossis complexes ntawm cov khoom xws li titanium / zirconium, silicon, thiab molybdenum.
Nws txoj kev tiv thaiv feem ntau yog ib qho kev thaiv lub cev, nrog me me lossis tsis muaj tus kheej - kho muaj peev xwm.
Thaum cov zaj duab xis passivation puas los ntawm acids lossis alkalis, corrosion ncaj qha cuam tshuam rau zinc txheej. Nws cov kua qaub thiab alkali tsis kam yog feem ntau me ntsis qis dua qhov siab -zoo chromate passivation.
Roj txheej
Cov roj zaj duab xis nws tus kheej yog txheej txheej hydrophobic organic uas tiv thaiv electrolytes (xws li dej thiab ntsev) los ntawm kev sib cuag ntawm qhov chaw.
Txawm li cas los xij, nws txoj kev tiv thaiv cov kua qaub thiab alkalis muaj zog heev, vim tias ntau cov tshuaj tuaj yeem yaj lossis nkag mus rau hauv cov yeeb yaj kiab roj.
5.Dab tsi yog qhov kev ua haujlwm dav dav ntawm txheej passivation ntawm galvanized coils?
Lub passivation txheej ntawm galvanized kauj tsis yog panacea; nws cov kev tiv thaiv tseem ceeb yog cov muaj zog acids thiab cov hauv paus.
Nws muaj kev tiv thaiv zoo rau atmospheric corrosion thiab nruab nrab ib puag ncig, nrog txwv los yog luv luv -lub sij hawm tsis muaj zog acids thiab bases.
Yog tias koj qhov chaw ua haujlwm muaj cov tshuaj, cov pH tshwj xeeb thiab hom tshuaj lom neeg yuav tsum raug ntsuas. Nyob rau hauv ib puag ncig tshuaj corrosive heev, stainless hlau, txhuas, los yog cov ntaub ntawv uas muaj zog organic coatings (xws li PVDF los yog epoxy) tej zaum yuav zoo dua.