1. Txoj Kev Kho Hniav Txhuam rau Monel 400
1.1 Mechanical Surface Treatments
Sib tsoo thiab polishing
Qhov no yog qhov yooj yim tshaj plaws kho tshuab. Siv cov cuab yeej abrasive (piv txwv li, daim ntaub emery, sib tsoo lub log, lossis pob zeb diamond pastes) los txhuam cov khoom ntawm Monel 400 tuaj yeem txo qhov roughness ntawm Ra 0.05-0.2 μm. Ib tug smoother nto txo qhov tsim ntawm crevices qhov twg corrosive media tuaj yeem sib sau ua ke, yog li txo qhov kev pheej hmoo ntawm kev xeb hauv zos xws li pitting thiab crevice corrosion. Nws yog dav siv rau precision Cheebtsam xws li li qub, twj tso kua mis shafts, thiab ntsuas qhov chaw nyob rau hauv corrosive ib puag ncig.
Txhaj tshuaj Blasting / Sand Blasting
Kev txhaj tshuaj blasting siv siab -kev txhaj tshuaj steel ceev los yog cov hlaws ceramic los cuam tshuam rau saum npoo, thaum xuab zeb blasting siv quartz xuab zeb lossis alumina abrasives. Ob txheej txheem tshem tawm cov nplai, xeb, thiab cov kab mob, thiab tsim kom muaj qhov sib xws, ntxhib nto (Ra 1.5-3.0 μm). Qhov kev kho no txhim kho kev sib raug zoo ntawm Monel 400 substrate thiab txheej txheej (xws li, xim, epoxy resin), thiab tsim nyog rau cov khoom loj - xws li cov tso tsheb hlau luam, cov kav dej, thiab cov khoom siv hluav taws xob.
Pickling thiab Descaling
Pickling feem ntau yog ua ke nrog kev kho tshuab. Cov kua qaub sib xyaw (feem ntau yog 5-10% nitric acid + 1-2% hydrofluoric acid) yog siv los ua kom yaj cov oxides thiab cov smut tsim thaum kub ua haujlwm lossis vuam. Tom qab pickling, saum npoo yog rinsed kom huv si nrog dej deionized thiab qhuav kom tsis txhob acid residue -induced corrosion. Cov txheej txheem no yog qhov yuav tsum tau ua ua ntej rau kev kho mob passivation lossis txheej txheej.
1.2 Kev Kho Hniav Tshuaj
Kev kho mob Passivation(Kev tsom xam nthuav dav hauv Tshooj 2)
Qhov no yog kev siv tshuaj kho mob ntau tshaj plaws rau Monel 400, uas tsim cov yeeb yaj kiab tsis zoo rau saum npoo.
Electroplating thiab Cladding
Rau qhov chaw corrosive heev, electroplating lossis cladding tuaj yeem siv rau ntawm Monel 400 nto. Cov ntaub ntawv txheej txheem muaj xws li kub, nyiaj, lossis Hastelloy C276. Electroplating tso ib txheej txheej hlau nyias (5-20 μm) los ntawm electrolysis, thaum cladding bonds ib txheej tuab tuab (0.5-5 mm) mus rau substrate los ntawm cov txheej txheem xws li tawg vuam lossis yob sib txuas. Cov coatings no cais Monel 400 substrate los ntawm cov xov xwm hnyav (xws li, anhydrous hydrofluoric acid, siab -kub tshuaj chloride) thiab siv rau hauv cov khoom siv tshuaj tshwj xeeb thiab cov khoom siv dav hlau.
Kev kho oxidation
Cua sov Monel 400 mus rau 400-500℃hauv huab cua qhuav los yog chav rau 1-2 teev ua cov tuab, adherent oxide zaj duab xis (NiO-CuO zaj duab xis sib xyaw) rau saum npoo. Cov yeeb yaj kiab no txhim kho cov hlau tsis muaj zog rau atmospheric corrosion thiab cov tshuaj lom neeg me me, thiab yog tus nqi- kho kom zoo rau cov khoom siv sab nraum zoov lossis qis - qhov chaw corrosion.
1.3 Organic Coating Treatments
Epoxy Resin Txheej
Epoxy txheej muaj zog adhesion thiab tshuaj tiv thaiv, thiab tuaj yeem tiv taus cov kua qaub, alkalis, thiab ntsev daws. Ib txheej 50-150 μm tuab epoxy feem ntau yog siv los ntawm kev txau lossis txhuam hniav, ua raws li kev kho ntawm chav tsev kub lossis kub siab. Nws yog feem ntau siv rau hauv ob sab hauv ntawm Monel 400 cia tso tsheb hlau luam thiab cov kav dej hauv cov nroj tsuag tshuaj.
Fluoropolymer Txheej
Cov txheej txheem xws li PTFE (polytetrafluoroethylene) lossis FEP (fluorinated ethylene propylene) muaj qhov tshwj xeeb ua rau cov kua qaub muaj zog, muaj zog alkalis, thiab siab -kub xov xwm. Cov txheej yog siv los ntawm sintering (thickness 20-50 μm) thiab ua ib qho tsis yog -stick, corrosion- resistant nto. Nws yog qhov zoo tagnrho rau Monel 400 Cheebtsam hauv siab -kev ua cov tshuaj purity thiab zaub mov- qib khoom.
2. Passivation Treatment puas tuaj yeem txhim kho Corrosion Resistance ntawm Monel 400?
2.1 Passivation Mechanism rau Monel 400
Txheej txheem Passivation: Monel 400 tivthaiv yog immersed nyob rau hauv a20-30% nitric acid dawsnyob rau hauv chav tsev kub rau 30-60 feeb (los yog tov tov ntawm 10-15% nitric acid + 0.5-1% sodium dichromate rau enhanced passivation).
Txoj Cai Tsim Yeeb Yam: Nitric acid ua raws li tus neeg sawv cev muaj zog oxidizing, ua kom cov oxidation ntawm npib tsib xee thiab tooj liab ntawm cov hlau nplaum los ua ib qhontom, uniform, thiab adherent passive zaj duab xis(thickness 0.5-2 μm). Cov zaj duab xis muaj ib tug compact crystalline qauv, uas thaiv kev nkag mus ntawm corrosive ions thiab tiv thaiv electrochemical tshuaj tiv thaiv ntawm lub substrate thiab corrosive nruab nrab.
2.2 Kev Txhim Kho Kev Ua Haujlwm Tom Qab Passivation
Txhim kho Localized Corrosion Resistance
Passivated Monel 400 qhia a2-3 npaug ntau dua pitting peev xwmnyob rau hauv chloride- muaj cov xov xwm (piv txwv li, dej hiav txwv) piv rau cov hlau tsis huv. Hauv 3.5% NaCl tov (simulated seawater) nyob rau hauv chav tsev kub, lub pitting muaj peev xwm nce los ntawm kwv yees li +0.1 V (vs. SCE) mus rau +0.3-0.4 V (vs. SCE), zoo suppressing qhov pib ntawm pitting corrosion.
Txhim kho Resistance rau Acid Erosion
Hauv cov kua qaub diluted (piv txwv li, 5% sulfuric acid, 10% hydrochloric acid), cov zaj duab xis passivated txo qhov corrosion ntawm Monel 400 los ntawm40–60%piv rau lub xeev unpassivated. Txawm li cas los xij, nws yuav tsum tau muab sau tseg tias cov yeeb yaj kiab passivated tsis muaj txiaj ntsig hauv cov concentrated hydrofluoric acid lossis kub concentrated sulfuric acid, vim tias cov xov xwm no tuaj yeem yaj cov oxide zaj duab xis.
Lub neej ua haujlwm ntev nyob hauv ib puag ncig hnyav
Hauv kev siv marine lossis ntug hiav txwv, passivated Monel 400 Cheebtsam muaj a1.5-2 lub sijhawm ua haujlwm ntev duadua li cov uas tsis muaj kev tiv thaiv, raws li cov yeeb yaj kiab ruaj khov tiv thaiv kev yaig los ntawm cov tshuaj tsuag ntsev thiab dej hiav txwv ntws.
2.3 Cov kev txwv ntawm Passivation Treatment
Cov zaj duab xis passivated yog rhiab heev rau qhov kub thiab txias. Thaum qhov kub siab tshaj 150 degree, cov yeeb yaj kiab qhov ntom ntom qis, thiab nws cov nyhuv tiv thaiv maj mam ploj mus.
Cov yeeb yaj kiab tuaj yeem raug puas los ntawm kev khawb lossis khawb. Yog tias cov yeeb yaj kiab raug ua txhaum cai, kev txhim kho hauv cheeb tsam tuaj yeem tshwm sim ntawm qhov chaw khawb, yuav tsum tau rov ua dua -passivation lossis kho nrog cov txheej txheem.
