Pitting corrosion yog ib qho chaw ua kom puas tsuaj heev ntawm titanium cua sov raj. Cov tshuaj chloride, fluoride thiab lwm yam halogen ions nyob rau hauv nruab nrab tawg ua kom tiav titanium dioxide passivation zaj duab xis ntawm me me defects, tsim cov me me anode pits cais. Corrosion tsim sab hauv sai sai nyob rau hauv qhov tob kev taw qhia, thaum cov hlau nyob ib puag ncig tseem tsis zoo. Cov pits txuas ntxiv thiab tho cov yeeb nkab phab ntsa kom ua rau cov pa tawm, nrog rau qhov tsis txaus ntseeg macroscopic corrosion thiab muaj zog randomness, uas yog ib qho kev ua tsis tiav ntawm titanium cov khoom siv hluav taws xob.
1. Electrochemical Formation Mechanism ntawm Pitting Corrosion
A dense and inert TiO₂ protective film naturally forms on the titanium surface. Thaum halogen ions adsorb mus rau micro khawb, suav nrog lossis tsis muaj zog ntawm cov txheej txheem passivation, lawv hloov cov pa atoms hauv oxide zaj duab xis los tsim cov titanium halide cov ntsiab lus soluble, rhuav tshem cov kev tiv thaiv hauv zos. Lub qhov dej sab hauv yog kaw los ntawm cov khoom siv corrosion, tsim lub kaw microenvironment nrog kev txuas ntxiv ntawm halogen ions thiab poob rau hauv pH tus nqi. Sab hauv ntawm lub qhov dej ua haujlwm raws li lub anode thiab dissolves tsis tu ncua, thaum lub sij hawm sab nrauv passivation cheeb tsam ua raws li qhov loj - cheeb tsam cathode kom ceev tus nqi tawg hauv lub qhov. Corrosion nyiam tshaj tawm vertically downwards es tsis kis kab rov tav, nws thiaj li nkag mus rau lub raj phab ntsa thiab ua rau nruab nrab to.
2. Cov hauj lwm zoo tshaj plaws rau Pitting Corrosion
Cov kua dej hloov pauv thaj chaw uas halogen- muaj cov tshuaj evaporates thiab precipitates concentrated ntsev stains;
Nto khawb, indentations thiab mechanical puas sab laug thaum ua thiab kev thauj mus los;
Cov cheeb tsam npog los ntawm av, nplai thiab sediment ua rau ion enrichment nyob rau hauv deposits;
Weld nto nrog tuab xoob oxidation txheej thiab tsis tiav passivation kho;
Cov dej tuag nrog ntev - lub sij hawm nruab nrab zoo li qub thiab cov ion txuas ntxiv mus.
3. Cov Ntsiab Tseem Ceeb Ua kom nrawm Titanium Pitting Corrosion
High concentration ntawm fluoride thiab chloride ions nyob rau hauv cov txheej txheem nruab nrab;
Qhov kev pabcuam siab kub tau txhim kho kev ua haujlwm ntawm halogen ions kom ua rau cov yeeb yaj kiab passivation;
Unremoved nto mechanical puas thiab residual vuam oxide daim tawv nqaij tom qab ua tiav;
Ntev - lub sij hawm kaw nrog cov kua corrosive residual txuas rau lub raj nto yam tsis tau ntxuav;
Tsis txaus thickness thiab tsis zoo compactness ntawm haiv neeg passivation zaj duab xis.
4. Txheej Txheem Tag Nrho -Txuas Kev Tiv Thaiv thiab Tswj Kev Ntsuas
① Tswj nruj me ntsis cov ntsiab lus halogen ion
Configure filtration thiab desalination cov cuab yeej los txo cov tshuaj chloride thiab fluoride concentration hauv cov kua dej.
② Tshem tawm kev puas tsuaj ntawm qhov chaw thiab tom qab-welding tiav
Tshem tawm khawb thiab burrs thaum ua tiav; ua pickling thiab passivation tom qab vuam rau strip oxide nplai thiab reconstruct uniform passivation zaj duab xis.
③ Tsis tu ncua ntxuav cov sediment thiab cov kua seem
Tshem tawm txhua qhov nruab nrab kom tiav thaum lub sijhawm kaw cov khoom siv, yaug cov raj xa dej kom tsis txhob muaj ntsev deposition thiab cov concentration hauv zos.
④ Ntxiv dag zog rau saum npoo passivation reinforcement
Txais siv anodic oxidation kev kho mob rau cov khoom ua kom tuab cov titanium oxide zaj duab xis thiab txhim khu kev tiv thaiv rau ion nkag mus.
⑤ Optimize kev khiav hauj lwm kub txwv
Zam kom tsis txhob ntev - lub sij hawm dhau - qhov kub thiab txias ua haujlwm kom txo qis cov tshuaj lom neeg ntawm corrosive anions.
5. Kev sib piv ntawm kev tiv thaiv kev cuam tshuam hauv cov txheej txheem sib txawv
表格
| Kev kho mob & kev ua haujlwm hom | Pitting Corrosion Risk | Daim ntawv thov tswv yim |
|---|---|---|
| Tsis siv neeg vuam oxide + siab fluorine / chloride nruab nrab | Tsis tshua muaj kev pheej hmoo ntawm kev nrawm pinpoint perforation | Tam sim ntawd pickling passivation thiab hloov dej zoo |
| Tshaj tawm -weld passivation + tu tu tsis tu ncua | Zoo heev suppress qhov pib thiab expansion | Standard ntau lawm thiab kev ua haujlwm specification |
| Anodic oxidation ntxiv dag zog + nruab nrab purification | Tsawg kawg pitting nyiam | Halogen-muaj cov txheej txheem ua haujlwm hnyav uas xav tau |
Xaus
Pitting corrosion ntawm titanium cua sov raj yog tshwm sim los ntawm qhov chaw tawg ntawm cov zaj duab xis passivation los ntawm halogen ions thiab occlusion- hom nrawm corrosion hauv qhov. Cov txheej txheem kev tiv thaiv tseem ceeb suav nrog kev tswj corrosive ion concentration hauv nruab nrab, tshem tawm qhov tsis xws luag uas yooj yim ua rau cov yeeb yaj kiab tawg, kho cov vuam oxidation txheej los ntawm kev kho mob passivation, thiab tsis txhob ntsev deposition los ntawm cov kua dej static residual. Kaw -Txoj kev tswj kev ua tiav, kev tiv thaiv saum npoo thiab kev ua haujlwm txhua hnub tuaj yeem tiv thaiv kom tsis txhob pom qhov tsis ua haujlwm o
f titanium cua sov raj.
