Cov ntsiab lus twg Endow Incoloy 825 nrog Kev Tiv Thaiv Corrosion Zoo Los Txo Cov Acids?
Incoloy 825 yog npib tsib xee- hlau-chromium superalloy tshwj xeeb uas tsim los rau hnyav txo cov kua qaub ib puag ncig, thiab nws cov corrosion kuj zoo heev yog vim muaj kev sib koom ua ke ntawm ntau yam tseem ceeb alloying, raws li cov lus qhia hauv qab no:
Nickel (Ni, ~ 38-46 wt%)
Raws li lub hauv paus matrix keeb ntawm Incoloy 825, npib tsib xee tsim ib tug ruaj khov austenitic qauv, uas muab cov alloy nrog zoo heev thermodynamic stability nyob rau hauv txo acid media. Nws tiv thaiv qhov txo cov tshuaj tiv thaiv ntawm corrosive ions thiab tiv thaiv cov matrix los ntawm kev ncaj qha eroded los ntawm acids xws li hydrochloric acid thiab sulfuric acid. Tsis tas li ntawd, npib tsib xee tuaj yeem txhim kho cov alloy lub peev xwm los tsim cov yeeb yaj kiab tsis tu ncua thiab txhim kho zaj duab xis adhesion rau matrix.
Chromium (Cr, ~ 19.5–23.5 wt%)
Chromium yog lub hauv paus tseem ceeb rau kev tsim cov yeeb yaj kiab tiv thaiv passive. Nws reacts nrog oxygen nyob rau hauv ib puag ncig los tsim ib tug ntomChromium oxide (Cr₂O₃)zaj duab xis rau ntawm qhov chaw alloy. Cov yeeb yaj kiab no tuaj yeem thaiv kev nkag mus ntawm cov corrosive anions (xws li Cl⁻, SO₄²⁻) hauv kev txo cov kua qaub, thiab muaj tus kheej zoo - kho cov khoom- thaum cov yeeb yaj kiab puas me ntsis, chromium hauv matrix tuaj yeem rov qab sai - ua cov yeeb yaj kiab tiv thaiv kom muaj kev tiv thaiv corrosion.
Molybdenum (Mo, ~ 2.5-3.5 wt%)
Molybdenum ho txhim khu cov hlau tsis kam rau hauv zos corrosion hauv kev txo cov kua qaub. Nws tuaj yeem muab tso rau hauv chromium oxide passive zaj duab xis los ua kom ruaj khov duachromium{0}}molybdenum composite oxide zaj duab xis, uas txhim kho cov zaj duab xis compactness thiab txo nws cov permeability rau corrosive ions. Ntxiv mus, molybdenum tuaj yeem cuam tshuam qhov tshwm sim ntawm pitting corrosion thiab crevice corrosion tshwm sim los ntawm Cl⁻ ions, uas yog ib qho tseem ceeb heev rau cov alloy lub neej kev pab cuam nyob rau hauv chloride- uas txo cov acid ib puag ncig.
Tooj liab (Cu, ~ 1.5-3.0 wt%)
Copper yog ib qho tseem ceeb hauv kev txhim kho corrosion kuj hauv kev txo cov kua qaub. Nyob rau hauv tsis muaj zog txo sulfuric acid los yog hydrochloric acid ib puag ncig, tooj liab yuav precipitate raws li ib tug zoo tooj liab theem nyob rau hauv lub alloy nto, uas ua raws li ib tug cathodic inhibitor los txo cov corrosion tam sim no ceev ntawm cov alloy thiab qeeb cov txheej txheem anodic dissolution ntawm lub matrix. Nws kuj tseem txhim kho cov hlau tsis kam tiv thaiv tsis yog -oxidizing acids xws li dilute hydrochloric acid.
Titanium (Ti, ~ 0.6-1.2 wt%)
Titanium yog ntxiv los ua ib qho chaw ruaj khov. Nws nyiam ua ke nrog cov pa roj carbon nyob rau hauv cov hlau tsimtitanium carbide (TiC)es tsis txhob chromium carbide. Qhov no tiv thaiv kev tsim ntawm chromium- cov cheeb tsam depleted ntawm cov ciam teb nplej, uas tiv thaiv intergranular corrosion los ntawm kev txo cov kua qaub ib puag ncig. Kev ruaj ntseg ntawm cov qoob loo ciam teb ntxiv kom ntseeg tau tias tag nrho corrosion tsis kam ntawm cov hlau tsis cuam tshuam.
Cov nyhuv synergistic ntawm cov ntsiab lus saum toj no ua rau Incoloy 825 tuaj yeem ua rau muaj kev tiv thaiv zoo heev hauv kev txo cov kua qaub ib puag ncig xws li hydrochloric acid, dilute sulfuric acid, thiab phosphoric acid.
