Kev nce qib hauv trivalent chromium passivation tshuab rau electroplated hluav taws xob cua sov raj

Kev nce qib hauv trivalent chromium passivation tshuab rau electroplated hluav taws xob cua sov raj

Kev tshawb fawb ntawm hexavalent chromium dawb passivation ntawm zinc tau ua tiav rau ntau tshaj kaum xyoo, feem ntau yog siv ob qho kev qhia: trivalent chromium passivation thiab chromium free passivation. Chromium free passivation systems muaj xws li titanate, molybdate, tungstate, tsis tshua muaj ntiaj teb thiab silicate [2]. Txawm hais tias cov chromium dawb passivation systems tsis muaj tshuaj lom thiab zoo ib puag ncig, lawv cov kev tiv thaiv corrosion thiab cov tsos tsis zoo li cov hexavalent chromium passivation, uas tsis tuaj yeem ua tau raws li cov kev cai ntawm electroplating ntawm cov khoom siv zoo tib yam, cia nyob ib leeg siab corrosion kuj yuav tsum tau ntawm automotive qhov chaw. electroplating. Yog li ntawd, chromium free passivation technology tsis tau siv dav hauv kev lag luam. Yog li ntawd, thev naus laus zis ntawm hexavalent chromium dawb passivation yog tsuas yog raws li trivalent chromium passivation technology, uas tau paub tab thiab siv hauv kev tsim khoom. Ib yam li qhov kev ua tau zoo ntawm niaj hnub alkaline cyanide dawb zinc plating txheej txheem tshiab tau dhau los ntawm cyanide zinc plating thiab acid zinc plating, qhov tseeb thib peb tiam trivalent chromium passivation kev ua tau zoo tau mus txog lossis txawm tias dhau cov txheej txheem hexavalent chromium passivation.

2.1 Thawj tiam trivalent chromium passivation

Lub ntsiab chelating tus neeg sawv cev yog fluoride, uas yog ib tug ruaj khov nyob rau hauv complexing nrog Cr (III) thiab muaj ib tug nyias txheej txheej. Yog li ntawd, cov xim ntawm cov txheej txheej zaj duab xis yog feem ntau silver dawb los yog xiav dawb, nrog tsis zoo corrosion kuj. Qhov nruab nrab ntsev tshuaj tsuag tsis pub tshaj 8-16H. Txhawm rau ua kom muaj kev tiv thaiv corrosion zoo, tsuas yog los ntawm kev sib khi, thiab xim tom qab sealing ua nyiaj dawb, nrog cov xim monotonous. Lub kaw lus no muaj qhov siab dua ntawm Cr (III) thiab ua haujlwm kub dua.

2.2 Thib ob tiam trivalent chromium passivation technology

Thaum ntxov thib ob tiam trivalent chromium passivation txheej txheem muaj oxidants, nrog corrosion kuj thiab zaj duab xis xim zoo ib yam li hexavalent chromium. Txawm li cas los xij, vim muaj cov hexavalent chromium hauv txheej zaj duab xis, nws raug tshem tawm. Cov txheej txheem thib ob nyob rau theem tom qab tsis muaj oxidants, thiab cov xim muaj xim kuj yog lub teeb. Cov yam ntxwv ntawm ob tiam trivalent chromium passivation tus neeg sawv cev yog kev siv cov organic complexing agents thiab ntxiv rau lwm cov hlau, uas zoo heev txhim kho corrosion kuj thiab muaj peev xwm tau txais cov xim sib txawv ntawm passivation films, xws li xiav dawb, multicolored, thiab dub. Cov kev cai rau kev khiav hauj lwm tej yam kev mob yog tsawg. Cov khoom lag luam muaj xws li Rodip248 los ntawm Atotech, Chromiting680 los ntawm Surtec, thiab TR-173 los ntawm Jasco, uas tau ua tiav hauv kev tsim khoom.

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