Mechanism thiab Composition ntawm Trivalent Chromium Passivation nyob rau hauv hluav taws xob cua sov Tube Electroplating

Mechanism thiab Composition ntawm Trivalent Chromium Passivation nyob rau hauv hluav taws xob cua sov Tube Electroplating

Qhov tseeb thib peb tiam trivalent chromium passivation technology

Lub sealing tus neeg sawv cev yog ncaj qha ntxiv rau lub thib ob tiam passivation tov, kov yeej lub drawback ntawm trivalent chromium passivation tsis muaj peev xwm kho tus kheej, zoo heev txhim kho corrosion kuj ntawm zaj duab xis txheej. Lub corrosion kuj ntawm cov zaj duab xis txheej tau mus txog los yog tshaj lub hexavalent chromium passivation txheej txheem, yog li nws ua tau raws li ib puag ncig tiv thaiv thiab siab corrosion kuj yuav tsum tau ntawm automotive tivthaiv electroplating. Lub Tuam Txhab Dipsol thiab EKEM Lub Tuam Txhab tau txais cov txheej txheem no. Cov khoom lag luam xws li Hongzheng's 251 thiab 252 trivalent chromium muaj yeeb yuj passivation, 261 trivalent chromium xiav dawb passivation, thiab 271 trivalent chromium dub passivation. Lawv tau ua tiav hauv kev tsim khoom.

3. Mechanism thiab muaj pes tsawg leeg ntawm trivalent chromium passivation

Cov tshuaj passivation zaj duab xis ntawm hexavalent chromium yog tsim los ntawm kev sib cais ntawm zinc, txo cov chromate thiab nag lossis daus ntawm trivalent chromium gel. Zaj duab xis muaj hexavalent chromium. Yog li ntawd, cov yeeb yaj kiab passivation muaj peev xwm kho tus kheej, tseem hu ua kev kho tus kheej muaj peev xwm. Lub trivalent chromium zaj duab xis txheej tsim zinc ions los ntawm kev sib cais ntawm zinc, thiab kev sib cais ntawm zinc ions ua rau nce pH tus nqi ntawm zinc nto tov. trivalent chromium ncaj qha reacts nrog zinc ions, hydroxide ions, thiab lwm yam., tsim insoluble tebchaw uas precipitate ntawm zinc nto, tsim ib tug passivation zaj duab xis. Cov tshuaj tiv thaiv tshwj xeeb yog raws li hauv qab no:

1. Zinc dissolution txheej txheem: Zn plus Ox (oxidant) → Zn2 plus plus Ox - ------- (cov tshuaj tiv thaiv formula 1)

Zn plus 2H plus → Zn2 plus plus H2 ↑ -------- (Reaction formula 1a)

2. Zaj duab xis txheej txheem: Zn2 ntxiv rau xCr (III) ntxiv rau yH2O → ZnCrxOy ntxiv 2YH ntxiv ------- (cov tshuaj tiv thaiv formula 2)

3. Dissolving process: ZnCrxOy plus 2yH plus → Zn2 plus plus xCr (III) plus yH2O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Trivalent chromium passivating agents feem ntau muaj cov hauv qab no:

Trivalent chromium Cr (III): Cov khoom tseem ceeb ntawm cov zaj duab xis passivation, thiab trivalent chromium tuaj yeem tau los ntawm chromium sulfate, chromium nitrate, chromium chloride, chromium acetate, thiab lwm yam.

Oxidizing tus neeg sawv cev: Tsim cov zinc ions, txhawb kev tsim cov membrane. Oxidizing agents tuaj yeem yog hydrogen peroxide, nitrate, halide, persulfate, cerium tetravalent, thiab lwm yam. Thaum lub sij hawm passivation txheej txheem siv oxidizing agents, vim tsis siv neeg nce pH, trivalent chromium yuav oxidized rau hexavalent chromium, uas yuav muab sib xyaw rau hauv txheej. , ua rau cov txheej txheem uas muaj hexavalent chromium. Yog li, cov yeeb yaj kiab tsim los ntawm oxidizing passivating cov neeg ua haujlwm muaj xim tsaus, tab sis nws tsis ua raws li ib puag ncig.

Lwm yam hlau: Feem ntau kho cov tsos xim thiab corrosion kuj, siv Mn, Sb, Mo, Ti, Fe, Co, Ni, Ce, thiab lwm yam lanthanide tsawg lub ntiaj teb hais.

Complexing tus neeg saib xyuas: tswj qhov ceev ntawm cov zaj duab xis tsim thiab stability ntawm passivation tov. Muaj zog complexation, qeeb zaj duab xis tsim ceev, nyias zaj duab xis txheej, thiab txawm tsis tuaj yeem tsim ib txheej zaj duab xis; Lub complexation yog tsis muaj zog heev, stability ntawm passivation kua yog tsis zoo, thiab cov zaj duab xis txheej yog npub. Complexing agents muaj fluorides, organic carboxylic acids, thiab lawv cov mixs.

Zaj duab xis txoj kev txhawb nqa: Kho cov xim ntawm zaj duab xis txheej. Xaiv cov yeeb yaj kiab sib txawv ua kom nrawm tuaj yeem tsim cov xim sib txawv. Muaj cov organic thiab inorganic anions, xws li NO3-, SO42-, - PO43-, F -, Cl -, SiO32-, SiF62-, BF4-, RCOOH.

Sealing tus neeg saib xyuas: Yuav kom kov yeej qhov kev tiv thaiv corrosion thiab lwm yam kev cov nyom ntawm cov txheej txheem thib ob ntawm tus neeg sawv cev passivation thiab ua tau raws li kev tiv thaiv ib puag ncig thiab kev tiv thaiv corrosion siab ntawm cov khoom siv tsheb electroplating, EKEM (Hongzheng) lub tuam txhab tau ua tiav hauv kev siv tshuab los ntawm xyoo ntawm kev tshawb fawb. Nws cov kev tshawb fawb qhia tau hais tias vim muaj tej kab txaij nyob rau hauv zaj duab xis txheej ntawm trivalent chromium passivation technology thiab tsis muaj peev xwm kho tus kheej, nws cov corrosion kuj raug cuam tshuam. Sealing tus neeg saib xyuas yog ncaj qha ntxiv rau cov tshuaj passivation, tus neeg saib xyuas sealing siv cov khoom siv nrog ib txoj kab uas hla mus txog nanoscale los sau cov micropores ntawm txheej passivation, ua rau cov zaj duab xis ntau compact, yog li zoo heev txhim kho corrosion kuj ntawm zaj duab xis txheej.

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