Muaj ntau txhiab tus alloys siv hauv kev lag luam, thiab tsuas yog qee qhov ntawm lawv tau qhia luv luv.
Lub peev xwm ntawm cov ntaub ntawv hlau los tiv thaiv nruab nrab corrosion hauv nruab nrab corrosive yog hu ua corrosion kuj ntawm hlau. Cov hlau ntshiab uas muaj kev tiv thaiv corrosion feem ntau ua tau raws li ib qho ntawm peb yam hauv qab no:
① Cov hlau uas muaj qhov kub siab thermal stability. Feem ntau, cov txheej txheem electrode muaj peev xwm siv tau los txiav txim, thiab ib qho uas muaj txiaj ntsig zoo yog qhov ruaj khov dua; Cov uas tsis tshua muaj kev ruaj ntseg, tsis ruaj khov. Cov hlau zoo nkauj uas muaj kev tiv thaiv corrosion zoo, xws li Pt, Au, Ag thiab Cu, yog nyob rau hauv pawg no.
② Cov hlau uas yooj yim passivated. Ntau cov hlau tuaj yeem tsim cov oxide zaj duab xis ntom ntom nrog cov nyhuv tiv thaiv hauv oxidizing nruab nrab, uas yog hu ua passivation. Qhov yooj yim tshaj plaws passivated hlau yog Ti, Zr, Ta, Nb, Cr thiab Al.
③ Ib qho hlau uas nws nto tuaj yeem tsim cov khoom siv corrosion uas yog insoluble thiab muaj kev tiv thaiv zoo. Qhov xwm txheej no tsuas yog tshwm sim thaum cov hlau nyob hauv qhov nruab nrab corrosion. Piv txwv li, Pb thiab Al yog nyob rau hauv H2SO4 tov, Fe yog nyob rau hauv H3PO4 tov, Mo yog nyob rau hauv hydrochloric acid, thiab Zn yog nyob rau hauv cov huab cua.
Yog li ntawd, raws li cov hauv paus ntsiab lus saum toj no, ib tug series ntawm corrosion-resistant alloys yog tau los ntawm alloying nyob rau hauv kev lag luam. Feem ntau, muaj peb txoj hauv kev:
① Txhim kho cov thermodynamic stability ntawm cov hlau los yog hlau, uas yog, ntxiv cov ntsiab lus alloy nrog siab thermodynamic stability rau cov qub uas tsis yog corrosion resistant hlau los yog alloy, thiaj li tsim ib qho kev daws teeb meem, txhim kho cov electrode muaj peev xwm ntawm cov hlau, thiab txhim khu nws corrosion. tsis kam. Piv txwv li, ntxiv Au rau Cu thiab Cu, Cr, thiab lwm yam rau Ni koom rau hauv pawg no. Txawm li cas los xij, txoj kev no ntawm kev ntxiv ntau cov hlau muaj txiaj ntsig tau txwv tsis pub siv rau hauv cov khoom siv hauv kev lag luam.
② Ntxiv cov ntsiab lus yooj yim passivated alloy, xws li Cr, Ni, Mo, thiab lwm yam, tuaj yeem txhim kho corrosion kuj ntawm lub hauv paus hlau. Chromium stainless hlau tuaj yeem ua tau los ntawm kev ntxiv qhov tsim nyog ntawm Cr rau hauv cov hlau.
Qhov kev sim qhia tau hais tias qhov kev tiv thaiv corrosion ntawm stainless hlau tsuas yog ua tiav thaum cov ntsiab lus Cr ntau dua 13 feem pua. Qhov siab dua cov ntsiab lus Cr, qhov zoo dua qhov corrosion kuj. Hom stainless hlau no muaj corrosion kuj zoo nyob rau hauv oxidizing nruab nrab, tab sis tsis zoo corrosion kuj nyob rau hauv tsis oxidizing nruab nrab xws li dilute sulfuric acid thiab hydrochloric acid. Qhov no yog vim tsis muaj oxidizing acid tsis yooj yim los ua cov alloy daim ntawv oxide zaj duab xis, thiab kuj muaj cov nyhuv dissolution ntawm oxide zaj duab xis.
Ntxiv cov ntsiab lus tsis muaj peev xwm txhawb cov qauv ntawm cov yeeb yaj kiab tuab ntawm cov npoo av yog lwm txoj hauv kev los npaj cov corrosion resistant alloys. Piv txwv li, steel muaj peev xwm tiv taus atmospheric corrosion vim yog tsim ntawm ib tug compact compound ntawm ferric hydroxide [FeOx · (OH) 23-2x] ntawm nws nto, uas muaj peev xwm ua si lub luag hauj lwm tiv thaiv. Qhov sib ntxiv ntawm Cu thiab P lossis P thiab Cr hauv cov hlau tuaj yeem txhawb kev tsim cov yeeb yaj kiab tiv thaiv, yog li cov hlau tsis tshua muaj hlau nrog atmospheric corrosion kuj tuaj yeem ua los ntawm Cu, P lossis P thiab Cr.
Hlau corrosion yog cov txheej txheem tsim kev phom sij tshaj plaws nyob rau hauv kev lag luam, yog li kev txhim kho thiab kev siv cov corrosion resistant alloys muaj qhov tseem ceeb ntawm kev sib raug zoo thiab kev lag luam.
