1. Core Functions ntawm Chromium (Cr)
Kev txhim kho corrosion kuj
Chromium muaj zog affinity rau oxygen. In corrosive media (such as oxidizing acids, salt solutions, and humid atmospheres), it can rapidly react with oxygen on the surface of the alloy to form a dense, adherent, and self-healingchromium oxide (Cr₂O₃) passive zaj duab xis. Cov yeeb yaj kiab no ua rau lub cev tsis muaj zog, cais cov matrix sab hauv los ntawm qhov chaw corrosive thiab tiv thaiv kev nkag mus ntxiv ntawm corrosive ions (xws li, Cl⁻, SO₄²⁻) rau hauv cov hlau, yog li txhim kho cov hlau tsis kam mus rau kev xeb, pitting corrosion, thiab crevice corrosion. Piv txwv li, nyob rau hauv npib tsib xee-raws li alloys xws li Inconel 625 thiab Hastelloy C276, ib tug chromium ntsiab lus ntawm 15% -25% yog tus yuam sij kom ntseeg tau lawv corrosion kuj nyob rau hauv hnyav ua tshuaj lom neeg ib puag ncig.
Siab -kub oxidation kuj txhim kho
Ntawm qhov kub siab (siab tshaj 600 degree), Cr₂O₃ zaj duab xis tsim rau ntawm cov hlau nplaum muaj cov thermal stability thiab tsis tshua muaj oxygen permeability. Nws tuaj yeem cuam tshuam qhov kev nthuav dav ntawm cov pa oxygen mus rau hauv cov hlau matrix, zam kev tsim cov oxides xoob (xws li NiO) uas muaj feem cuam tshuam. Qhov no ua rau npib tsib xee-raws li cov alloys kom muaj kev ncaj ncees thiab kev ua haujlwm ruaj khov nyob rau hauv siab -kub oxidative cua (xws li, industrial furnaces, roj turbine Cheebtsam).
Txhim kho cov alloy matrix
Chromium tuaj yeem yaj mus rau hauv nickel matrix los ua ib qhokev hloov khoom siv tshuaj, uas ua rau kom lub lattice distortion ntawm matrix thiab hinders lub zog ntawm dislocations. Cov khoom no-cov tshuaj tiv thaiv kev ua kom muaj zog tuaj yeem txhim kho chav tsev- kub thiab siab - qhov kub thiab txias lub zog ntawm alloy yam tsis tau txo nws qhov hnyav. Tsis tas li ntawd, chromium tuaj yeem txhawb cov nag lossis daus ntawm cov theem ntxiv (piv txwv li, 'theem, M₂₃C₆ carbide) hauv qee cov npib tsib xee-raws li superalloys, ntxiv dag zog rau siab -kub creep kuj ntawm cov hlau.
2. Core Functions ntawm Molybdenum (Mo)
Txhim khu kev tiv thaiv rau localized corrosion
Hauv kev txo cov corrosive media (xws li hydrochloric acid, sulfuric acid, thiab phosphoric acid), qhov twg chromium cov nyhuv passivation tsis muaj zog, molybdenum plays lub luag haujlwm tseem ceeb hauv kev tiv thaiv corrosion. Molybdenum tuaj yeem ua kom muaj txiaj ntsig zoo ntawm cov hlau nplaum thiab ua rau lub ntsej muag molybdenum oxide (MoO₃) zaj duab xis uas muaj zog corrosion kuj. Qhov tseem ceeb tshaj, molybdenum tuaj yeem cuam tshuam qhov pib thiab nthuav tawm ntawm pitting corrosion tshwm sim los ntawm Cl⁻ ions. Nws txo cov solubility ntawm passive zaj duab xis nyob rau hauv chloride- muaj cov kev daws teeb meem thiab ua rau kom qhov tseem ceeb pitting kub (CPT) ntawm cov alloy, ua npib tsib xee-raws li alloys haum rau marine, roj thiab roj extraction, thiab tshuaj industries nrog siab chloride ion concentrations. Piv txwv li, Hastelloy C276 nrog cov ntsiab lus molybdenum ntawm 15% -16% pom zoo pitting corrosion kuj nyob rau hauv seawater thiab chloride-muaj cov kua qaub.
Khoom- daws qhov muaj zog thiab siab -kub creep kuj txhim kho
Molybdenum muaj lub vojvoog loj atomic thiab tuaj yeem tsim cov khoom siv ruaj khov heev nrog cov nickel. Nws qhov sib ntxiv ua rau muaj qhov cuam tshuam loj ntawm lattice, uas cuam tshuam zoo rau kev txav ntawm dislocations thiab diffusion ntawm atoms ntawm qhov kub thiab txias. Qhov no zoo heev txhim kho covsiab - qhov kub thiab txiasthiabcreep kujntawm lub alloy. Nyob rau hauv npib tsib xee-raws li superalloys siv rau roj turbine hniav thiab turbine disks, molybdenum yog ib qho tseem ceeb ntxiv dag zog rau lub ntsiab uas pab cov alloy tswj kev ruaj ntseg nyob rau hauv ntev - lub sij hawm siab - kub thiab siab - kev nyuaj siab.
Txhim khu kev tiv thaiv kom tsis txhob acid corrosion
Molybdenum tuaj yeem txhim kho cov hlau tsis kam tiv thaiv corrosion hauv kev txo cov kua qaub (xws li dilute hydrochloric acid, dilute sulfuric acid). Tsis zoo li chromium, uas yog nquag mus rau passivation tsis ua hauj lwm nyob rau hauv txo ib puag ncig, molybdenum tuaj yeem tsim cov complexes ruaj khov nrog cov xov xwm corrosive, txo tus nqi corrosion ntawm alloy matrix. Qhov no ua rau npib tsib xee-raws li alloys uas muaj molybdenum zoo tagnrho cov ntaub ntawv rau cov khoom siv nyob rau hauv cov tshuaj lom neeg kev lag luam uas tswj txo acid media.
3. Synergistic nyhuv ntawm Chromium thiab Molybdenum
Chromium muab cov zaj duab xis ruaj khov nyob rau hauv oxidizing ib puag ncig, thaum molybdenum txhim khu kev tiv thaiv corrosion ntawm zaj duab xis hauv kev txo qis thiab chloride- muaj ib puag ncig.
Cov khoom sib xyaw ua ke- cov kev daws teeb meem ntxiv zog ntawm ob lub ntsiab lus tseem ceeb txhim kho lub zog thiab nkag siab ntawm cov hlau ntawm ob qho tib si hauv chav tsev kub thiab kub kub, thaum tuav zoo toughness thiab processability.
