Pitting xeb: ua. tiv thaiv co tiv thaiv xeb txoj kev

Corrosion hu ua kev puas tsuaj ntawm tus nto active ntaub ntawv raws li ib tug tshwm sim ntawm niaj redox dab. Kev puas tsuaj ntawm cov ntaub ntawv uas khaubncaws sab nraud povtseg ua rau tsis muaj zog, hluav taws xob conductivity, nce brittleness thiab lwm yam khoom ntawm tus hlau inhibition.

Nyob rau hauv lub lag luam los ntawm cov hlau khoom uas raug mus rau lub ua los ntawm ntau hom thiab hom, cov uas sawv tawm Pitting. Nws yog feem ntau txaus ntshai thiab unpredictable.

pitting xeb

Nyob rau saum npoo ntawm cov hlau cov khoom nws yog tsis yooj yim dua rau saib me me depressions nyob rau hauv cov nqe lus ntawm xim av los yog xim av. Cov zaum hu Pitting point, thiab cov txheej txheem ntawm lawv cov tsos - Pitting. Nws tshwm sim rau ntawm qhov chaw ntawm cov ntaub ntawv nyob rau hauv kev sib cuag nrog hiav txwv dej dlaws ntawm ntau yam ntsev, sib txhoj puab heev kua thiab hnov lwm tsis zoo yam.

Pitting xeb muaj feem xyuam rau tsuas yog tus passive co thiab alloys, tsim tsuas yog nyob rau xeb txheej los yog mus rau qhov chaw uas muaj ntau yam tsis zoo. "Point ulcers" tej zaum yuav cuam tshuam nrog lub lag luam ntawm ntau yam khoom los ntawm nyias week thiab tej daim mus rau lub tuab-walled units. Ntxiv mus, lawv cov tsos xeb tswj lub tsim ntawm tej kab nrib pleb yog tshuam txo muab cov ntaub ntawv uas cov yam ntxwv.

Scheme hlau puas

Mus qhib Pitting yuav tsum tau rau ntawm ob tug reactants - activators thiab sequestrants. Raws li ib tug activator anions ntawm cov tshuaj feem ntau ua, bromine, iodine - lawv muaj nyob rau hauv feem ntau tej kev kawm nyob rau hauv uas hlau khoom uas ua. Lawv adsorbed mus rau lub hlau nto thiab tsim nrog nws Cheebtsam soluble ceg.

Raws li passivating dej los yog hydroxyl pab pawg neeg feem ntau ua. Tam sim ntawd puas tsuaj txheej txheem hais raws li cov nram qab no tswvyim:

1. Activator ions yog adsorbed rau ntawm qhov chaw ntawm tus tiv thaiv (oxide) zaj duab xis.
2. Muaj yog ib tug txheej txheem ntawm hloov chaw ntawm cov pa ions rau tus txheej txheem ntawm lub activator ions.
3. Ib tug loj npaum li cas ntawm soluble ions, uas cov zaj duab xis so.

Raws li ib tug tshwm sim, ib tug tej zaum txawv tshwm sim rau ntawm qhov chaw ntawm cov ntaub ntawv uas yuav ua rau lub zos dej tsaws ntxhee tshuab txais sai anodic txheej txheem. Activator ions li tsiv mus rau cov chaw zov me nyuam ntawm puas, vim uas pitting xeb loj zuj zus.

Hom ntawm pitting xeb

Hom pitting xeb mas nws txawv nyob ntawm seb ib puag ncig tej yam kev mob, tsuas yog nyob rau hauv lub kub, pH, tshuaj muaj pes tsawg leeg ntawm tshuaj. Nyob rau hauv tus ntawm cov yam tseem ceeb mas nws txawv daim ntawv qho to me me thiab lawv kho. Yog li, raws li qhov loj ntawm lub cais point kev puas tsuaj:

• me me - dot loj tsawg tshaj li 0.1 hli;
• pa - lub lub cheeb ntawm lub pits nws sib txawv 0.1 thiab lub 1 hli;
• ulcerative thaum tsim ntau tshaj 1 hli nyob rau hauv txoj kab uas hla.

Nyob rau hauv lub qhov chaw ntawm pitting xeb yuav ua tau qhib los yog kaw. Nyob rau hauv thawj cov ntaub ntawv, mus ntes ib co kua nplaum ntawm kev puas tsuaj yog yuav luag tsis yooj yim sua - yog tsim nyog los siv tshwj xeeb seev. Qhov no hom ntawm xeb feem ntau ua rau breakdowns.

Qhib rusting hnov mus rau lub liab qab qhov muag. Feem ntau pitting hauj lwm ua ke rau hauv ib qhov chaw. Thaum zoo li no tshwm sim tsis muaj degradation ntawm cov khoom nyob rau hauv qhov tob thiab nyob rau hauv dav, vim hais tias cov neeg uas muaj cov loj loj cheeb tsam tsis xws luag.

daim ntawv ntawm qho to

Daim ntawv ntawm Pitting nyob rau hauv lub voids nyob rau hauv lub siv lead ua ntxaij ntoo uas yog tsim nyob rau hauv thawj theem ntawm xeb txheej txheem. Qhov feem ntau heev tsim ntawm lus zoo - lawv tshwm sim rau ntawm qhov chaw ntawm stainless steel, carbon thiab tsawg alloy steels, txhuas, chromium, npib tsib xee alloys, hlau.

Hemispherical ulcers tsim raws li ib tug tshwm sim ntawm lub isotropic nyias mus nyias. Qhov no tus txheej txheem yog zoo li electro. Nyob rau hauv ib feem no qhia txog lub ci hauv qab ntawm lub semi-ncig ua si nraum zoov. Feem ntau cov raug rau tej degradation, titanium, txhuas, npib tsib xee thiab cobalt khoom, raws li zoo raws li cov qauv ntawm cov tantalum. Kwv yees li tib yam tsiaj nws muaj ib tug Pitting ntawm stainless steels.

Tsis tas li ntawd, Pitting tej zaum yuav polyhedral thiab faceted. "Ulcers" ntawm lub yav tas hom mas feem ntau yog ua ke nrog lwm yam, uas ua rau yus mus rau ib tug loj hemispherical kev puas tsuaj.

ua rau

Lub ntsiab ua rau tshwm sim ntawm pitting xeb yog tiv thaiv cov ntau lawm technology thiab cov neeg kho tshuab txiav txim rau ntawm cov khoom. Raws li ib tug tshwm sim ntawm teeb nyob rau hauv lub hlau casting tshuab tshwm sim ntau yam microinclusions uas cuam tshuam nws cov qauv. Feem ntau cov menyuamuas yuav hu ua zeb scale.

Vim tus neeg kho tshuab kev txiav txim yog heev feem ntau rau ntawm qhov chaw ntawm cov khoom pib tsim Pitting. Yog vim li cas rau qhov no dag nyob rau hauv txoj kev puas tsuaj ntawm sab sauv tiv thaiv zaj duab xis, cuam tshuam lub internal qauv, tawm hauv tus nto ntawm lub grain ib thaj tsam. Feem ntau cov txheej txheem ntawm activating tshaj yuav yog tus dynamic nyhuv, uas ua rau yus mus rau lub tsos ntawm microcracks.

Pitting xeb hlau yog tsim sai rau ntxhib chaw, raws li zoo raws li nyob rau hauv tus ntawm txhoj puab heev xov xwm - lub hiav txwv dej, acidic daws teeb meem.

Txoj kev kev tiv thaiv kom hlau los ntawm xeb Pitting

Yuav kom tiv thaiv hlau cov khoom tiv thaiv pitting siv peb txoj kev:

1. Ntaus kaw tshuab siv daws cov teeb meem ntawm alkaline tebchaw, sulfates, chromates.
2. Introduction ntawm cov khoom Cheebtsam muaj kuj mus rusting ntawm ib tug taw tes - ntawm molybdenum, chromium, pob zeb ntais.
3. Siv anode thiab cathode technology tsim ib tug tiv thaiv txheej.

Tag nrho cov kev los tiv thaiv co ntawm xeb yog tsuas muaj feem xyuam rau zus tau tej cov, kev thov rau high-tech cov khoom thiab ib tug loj capital peev. Nyob rau hauv lub neej txhua hnub yog kiag li tshem tawm txoj kev pheej hmoo ntawm pitting tsis yooj yim sua. Nws muaj peev xwm tsuas tsis muaj zog tus tsis zoo kuj yam los ntawm:

• thov anticorrosive coatings;
• txhim kho lub lag luam los ntawm tej khoom;
• kom txhob muaj cov theem ntawm acidity, uas yog nyob rau hauv kev sib cuag nrog rau cov khoom siv.

Tab sis qhov zoo tshaj thiab muaj txoj kev yog mus ua tib zoo polished: txo nto roughness, koj ib txhij tsub kom nws xeb kuj. Tab sis rau qhov zoo tshaj plaws kev tshwm sim, zoo dua kev siv ntawm tag nrho txoj kev los tiv thaiv co tiv thaiv xeb nyob rau tib lub sij hawm.