Corrosion Resistance Yam ntxwv ntawm K500 monel - Kev Paub

1. Kev tiv thaiv zoo heev rau chloride-induced Pitting thiab Crevice Corrosion

Qhov no yog qhov tseem ceeb tshaj plaws corrosion kuj feature ntawm Monel K500. The alloy forms a dense, adherent, and self-healing passive film composed of nickel and copper oxides on its surface. Cov zaj duab xis passive no tsis tshua muaj permeability rau chloride ions, zoo tiv thaiv chloride adsorption, nkag mus, thiab tom qab pib ntawm pitting ntawm cov khoom tsis xws luag (xws li, inclusions, grain ciam teb).

Kev ua tau zoo: Hauv dej hiav txwv zoo li qub lossis ntws dej hiav txwv, brine, lossis chloride -muaj cov kev daws teeb meem hauv chav rau nruab nrab kub (<100°C), Monel K500 exhibits negligible pitting or crevice corrosion, with a corrosion rate of less than 0.025 mm/year.

Daim ntawv thov scenarios: Nws yog dav siv nyob rau hauv marine Cheebtsam (offshore platform fittings, seawater pipelines, propeller shafts) thiab desalination cog khoom, qhov twg chloride concentrations mus txog 100,000 ppm los yog siab dua.

2. Kev tiv thaiv zoo rau Uniform Corrosion hauv Neutral thiab Weakly Alkaline Media

Monel K500 tswj kev ruaj ntseg hauv feem ntau nruab nrab thiab tsis muaj zog alkaline ib puag ncig, suav nrog cov dej ntuj, cov dej txias ua haujlwm, thiab cov tshuaj alkaline tshuaj daws teeb meem (xws li, sodium hydroxide daws nrog cov ntsiab lus qis dua 50% ntawm chav sov). Nws cov qauv corrosion tsis zoo nyob rau hauv cov xov xwm no yog tsawg heev, deb tshaj cov pa roj carbon steels thiab zoo tib yam stainless hlau.

Mechanism: Cov npib tsib xee- tooj liab passive zaj duab xis tseem nyob twj ywm nyob rau hauv uas tsis yog - oxidizing nruab nrab / tsis muaj zog alkaline tej yam kev mob, zam tsis tu ncua cov khoom dissolution tshwm sim los ntawm zaj duab xis tawg.

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3. Kev tiv thaiv corrosion los ntawm kev txo cov kua qaub thiab ntsev daws

Lub alloy qhia tau hais tias zoo corrosion kuj nyob rau hauv txo cov acid ib puag ncig uas tsis muaj oxidants muaj zog, xws li:

Dilute hydrochloric acid (concentration<10%) at room temperature;

Dilute sulfuric acid nyob rau hauv tsis muaj huab cua (oxidizing agents accelerate corrosion);

Organic acids (piv txwv li, acetic acid, citric acid) feem ntau siv hauv cov khoom noj thiab tshuaj lag luam.

Tsis tas li ntawd, Monel K500 yog cov tshuaj tiv thaiv corrosion los ntawm ntau cov tshuaj ntsev (xws li sodium chloride, potassium chloride, magnesium chloride), ua rau nws tsim nyog rau cov khoom siv hauv kev tsim ntsev thiab tshuaj ntsev cov txheej txheem.

4. Resistance to Stress Corrosion Cracking (SCC) nyob rau hauv ib puag ncig tshwj xeeb

Piv rau austenitic stainless hlau (xws li, 304, 316), Monel K500 muaj qhov cuam tshuam qis dua rau kev ntxhov siab corrosion cracking hauv chloride- muaj ib puag ncig ntawm qhov kub nruab nrab. Qhov kom zoo dua no yog qhov tseem ceeb rau cov khoom siv uas raug rau kev ntxhov siab, xws li marine fasteners thiab cov hlab ntsha siab.

Kev txwv: Thaum kub siab tshaj 200 degree, los yog nyob rau hauv ib puag ncig uas chlorides coexist nrog oxidants muaj zog (xws li, ferric ions, hypochlorite), SCC tsis kam ntawm Monel K500 yuav poob, yuav tsum tau ceev faj soj ntsuam ntawm cov kev pab cuam tej yam kev mob.

5. Kev tiv thaiv corrosion -corrosion thiab Cavitation Corrosion

Thanks to its high strength (achieved via precipitation hardening) and dense passive film, Monel K500 has excellent resistance to erosion-corrosion (caused by high-velocity fluid carrying solid particles) and cavitation corrosion (caused by bubble collapse in flowing media). Qhov no ua rau nws yog ib qho khoom siv zoo tshaj plaws rau siab - ceev rotating Cheebtsam, xws li lub twj tso kua mis impellers thiab nkoj propellers, uas yog nquag yaig -corrosion puas.

Cov kev txwv tseem ceeb ntawm Corrosion Resistance

Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias Monel K500 tsis yog universally corrosion-resistant thiab muaj kev txwv kev ua tau zoo hauv cov cheeb tsam hauv qab no:

Muaj zog oxidizing acids: Nws yog qhov cuam tshuam rau corrosion hnyav nyob rau hauv concentrated nitric acid, kub concentrated sulfuric acid, los yog tov acid systems uas muaj oxidants.

High -kub concentrated chloride ib puag ncig: Ntawm qhov kub siab tshaj 150℃thiab chloride concentrations tshaj 150,000 ppm, qhov ruaj khov ntawm cov yeeb yaj kiab passive txo qis, uas ua rau muaj kev cuam tshuam hauv zos.

Ammonia- muaj ib puag ncig: Nyob rau hauv siab -kub ammonia lossis ammonium hydroxide daws, Monel K500 yuav raug kev txom nyem los ntawm kev xaiv leaching ntawm tooj liab, txo nws cov corrosion kuj thiab txhua yam khoom.