1. Stainless hlau tsis xeb, nws kuj tsim ib qho oxide rau ntawm qhov chaw.

Lub tshuab tsis muaj xeb ntawm tag nrho cov hlau stainless tam sim no nyob rau hauv kev ua lag luam yog vim muaj Cr.Lub hauv paus yog vim li cas rau corrosion kuj ntawm stainless hlau yog passive zaj duab xis txoj kev xav.Lub npe hu ua passivation zaj duab xis yog ib zaj duab xis nyias uas yog tsim los ntawm Cr2O3 ntawm cov hlau tsis muaj steel.Vim tias muaj cov yeeb yaj kiab no, qhov corrosion ntawm stainless hlau substrate nyob rau hauv ntau yam xov xwm yog hindered, thiab qhov tshwm sim no hu ua passivation.

Muaj ob lub sijhawm rau kev tsim cov yeeb yaj kiab passivation zoo li no.Ib qho yog tias stainless hlau nws tus kheej muaj peev xwm ntawm tus kheej-passivation.Qhov no tus kheej-passivation muaj peev xwm nce nrog nce ntawm chromium cov ntsiab lus, yog li nws muaj xeb kuj;Lwm yam Kev tsim kho ntau dua yog tias cov hlau tsis muaj hlau ua ib zaj duab xis passive nyob rau hauv cov txheej txheem ntawm raug corroded nyob rau hauv ntau yam aqueous daws (electrolytes) los cuam tshuam corrosion.Thaum cov zaj duab xis passivation puas lawm, ib zaj duab xis passivation tshiab tuaj yeem tsim tam sim ntawd.

Stainless hlau passivation zaj duab xis muaj peev xwm tiv thaiv corrosion, muaj peb yam ntxwv: ua ntej, lub thickness ntawm passivation zaj duab xis yog tsis tshua muaj nyias, feem ntau tsuas yog ob peb microns nyob rau hauv cov ntsiab lus ntawm chromium> 10.5%;qhov thib ob yog qhov tshwj xeeb lub ntiajteb txawj nqus ntawm cov zaj duab xis passivation Nws yog ntau tshaj qhov tshwj xeeb lub ntiajteb txawj nqus ntawm lub substrate;Ob tus yam ntxwv no qhia tau hais tias cov zaj duab xis passivation yog nyias thiab ntom, yog li ntawd, cov zaj duab xis passivation yog ib qho nyuaj rau nkag mus los ntawm corrosive nruab nrab kom sai corrode lub substrate;qhov thib peb feature yog chromium concentration piv ntawm passivation zaj duab xis Lub substrate yog ntau tshaj peb zaug ntau dua;Yog li ntawd, cov zaj duab xis passivation muaj siab corrosion kuj.

2. Stainless hlau kuj yuav corroded nyob rau hauv tej yam kev mob.

Daim ntawv thov ib puag ncig ntawm stainless hlau yog qhov nyuaj heev, thiab cov ntshiab chromium oxide passivation zaj duab xis tsis tuaj yeem ua tau raws li qhov yuav tsum tau muaj kev tiv thaiv corrosion siab.Yog li ntawd, nws yog ib qho tsim nyog yuav tsum tau ntxiv cov ntsiab lus xws li molybdenum (Mo), tooj liab (Cu), nitrogen (N), thiab lwm yam rau cov hlau raws li kev siv sib txawv los txhim kho cov muaj pes tsawg leeg ntawm cov zaj duab xis passivation thiab txhim kho corrosion kuj. stainless hlau.Ntxiv Mo, vim tias cov khoom siv corrosion MoO2- nyob ze rau ntawm lub substrate, nws txhawb nqa kev sib koom ua ke thiab tiv thaiv corrosion ntawm substrate;qhov sib ntxiv ntawm Cu ua rau cov zaj duab xis passive nyob rau saum npoo ntawm stainless hlau muaj CuCl, uas yog txhim kho vim nws tsis cuam tshuam nrog corrosive nruab nrab.Corrosion tsis kam;Ntxiv N, vim hais tias cov zaj duab xis passivation yog enriched nrog Cr2N, qhov concentration ntawm Cr nyob rau hauv lub passivation zaj duab xis yog nce, yog li txhim kho corrosion kuj ntawm stainless hlau.

Lub corrosion kuj ntawm stainless hlau yog conditional.Ib hom ntawm stainless hlau yog corrosion resistant nyob rau hauv ib tug tej yam nruab nrab, tab sis tej zaum yuav puas nyob rau hauv lwm yam nruab nrab.Nyob rau tib lub sij hawm, corrosion kuj ntawm stainless hlau kuj yog txheeb ze.Txog tam sim no, tsis muaj cov hlau tsis muaj hlau uas tsis muaj corrosive hauv txhua qhov chaw.

3. Qhov tshwm sim tshwm sim.

Stainless hlau muaj Cr thiab tsim cov chromium oxide zaj duab xis rau ntawm qhov chaw, uas poob tshuaj lom neeg thiab hu ua lub xeev passivated.Txawm li cas los xij, yog tias lub kaw lus austenitic dhau los ntawm qhov kub ntawm 475 ~ 850 ℃, C yuav ua ke nrog Cr los ua chromium carbide (Cr23C6) thiab precipitate hauv cov siv lead ua.Yog li ntawd, cov ntsiab lus Cr nyob ze ntawm ciam teb nplej tau txo qis heev, dhau los ua thaj tsam Cr-tsis zoo.Lub sijhawm no, nws qhov kev tiv thaiv corrosion yuav raug txo, thiab nws yog qhov tshwj xeeb tshaj yog rhiab rau corrosive ib puag ncig, yog li nws yog hu ua sensitization.Kev hnov ​​​​mob feem ntau yuav corrode nyob rau hauv kev siv ib puag ncig ntawm oxidizing acid.Tsis tas li ntawd, muaj cov vuam cua sov ua rau thaj tsam thiab kub dabtsi yog khoov ua zones.

4. Yog li nyob rau hauv dab tsi tshwm sim yuav stainless hlau corrode?

Qhov tseeb, stainless hlau tsis tas yuav tsis muaj xeb, tab sis nws tus nqi corrosion yog qis dua li lwm cov hlau nyob hauv ib puag ncig, thiab qee zaum nws tuaj yeem tsis quav ntsej.