Lub passivation ntawm hlau yog ze ze rau electroplating. Cov kev kho tshwj xeeb uas yuav tsum tau ua rau cov ntaub ntawv nyuaj ua ntej plating tuaj yeem pom hauv ntau phau ntawv thiab phau ntawv. Feem ntau ntawm cov laj thawj yog vim li cas cov ntaub ntawv no nyuaj rau cov phaj yog ze rau lawv cov bluntness. Cov lus qhuab qhia thib plaub tau tham luv luv txog qhov teeb meem ntawm kev ua kom dhau thiab ua kom muaj zog. Cov lus qhuab qhia no coj mus rau hauv tus account qhov tseem ceeb ntawm qhov teeb meem no rau electroplating, thiab tom qab ntawd tham txog ntau yam ntxiv. Passivation thiab activation yog tus cwj pwm txawv: passivation ua rau lub peev xwm electrode ntawm cov hlau hloov mus rau qhov zoo, thaum ua kom nws hloov mus rau qhov tsis zoo. Los ntawm kev ntsuas lub peev xwm-lub sij hawm nkhaus ntawm cov hlau hauv cov xov xwm sib txawv, lub xeev passivation thiab ua kom muaj zog tuaj yeem txiav txim siab. Passivation yog vim tias txheej txheej passivation (feem ntau yog txheej oxide) yog tsim rau ntawm cov hlau ntshiab lossis hlau. Tom qab sim tshem tawm cov txheej txheej passivation, cov hlau ntshiab lossis hlau hloov pauv los ntawm lub xeev passivation mus rau lub xeev qhib. Thaum lub sij hawm electroplating, txheej txheej plating tsuas yog tso rau ntawm qhov chaw ua haujlwm tag nrho thiaj li tau txais kev sib txuas zoo thiab zoo li qub. Yog tias muaj txheej txheej passivation ntawm qhov chaw, ntawm ib sab, qhov kev ncua deb ntawm cov txheej plating thiab cov hlau atoms ntawm lub hauv paus lub cev yog loj, thiab universal gravitation raug txo; ntawm qhov tod tes, nws yog tsis yooj yim sua los tsim ib tug hlau daim ntawv cog lus ntawm ob hlau atoms.
Txawm hais tias cov hlau yuav passivate los yog tsis muaj feem xyuam rau qhov nruab nrab, tab sis qhov tseem ceeb tshaj, nws nyob ntawm qhov xwm ntawm cov hlau nws tus kheej. Hauv qhov no, qhov loj ntawm cov hlau "passivity coefficient" tuaj yeem sib piv: cov hlau uas muaj qhov sib txuam loj dua yog yooj yim dua rau passivate thiab cov txheej passivation yog denser. Lub passivation coefficient ntawm qee cov hlau yog: titanium, 2.44; aluminium, 0.82; chromium, 0.74; beryllium, 0.73; molybdenum, 0.49; magnesium, O. 47; nickel, 0.37; xyaum, 0.20; hlau, 0.18; manganese, 0.13; zinc, 0,024; calcium, tooj liab, lead, tin, -0 00. Titanium yog cov hlau uas yooj yim passivated, thaum calcium, tooj liab, lead, thiab tin tsis yooj yim passivated.
Ntxiv ib qho loj feem ntawm ib lossis ntau cov hlau nrog ib qho loj passivation coefficient rau cov hlau uas tsis tshua muaj passivation coefficient los ua ib qho alloy yuav ua rau nws cov passivation yooj yim, yog li txhim kho corrosion kuj. Piv txwv li, ntxiv ntau dua 13 feem pua ntawm chromium rau hlau ua ferritic lossis martensitic stainless hlau (xws li 0Crl3ib 4crl3); ntxiv passivated titanium, thiab lwm yam., ua ntau corrosion-resistant austenitic stainless hlau, raug Nws yog non-ferromagnetic lCrl8Ni9Ti stainless hlau (muaj 18 feem pua chromium, 9 feem pua nickel thiab me me ntawm titanium). Lub molybdenum-muaj stainless hlau muaj zoo sulfuric acid corrosion kuj. Lub corrosion kuj ntawm electroplated zinc-nickel alloy thiab txawm zinc-hlau alloy yog zoo dua li ntawm electroplated ntshiab zinc. Txhawm rau hloov cov passivation ntawm hexavalent chromium zinc plating, nickel ntsev thiab cobalt ntsev feem ntau yog ntxiv rau tam sim no trivalent chromium passivation tov. Txawm hais tias muaj ntau txoj kev tshawb fawb ntawm chromium-dawb passivation, nws cov corrosion kuj tsis zoo li cov chromium-muaj passivation. Qee tus neeg xav tias qhov kev cia siab tshaj plaws ntawm chromium-free passivation yog kev siv cov titanium ntsev thiab cov hlau tsis tshua muaj hauv ntiaj teb, ua raws li molybdate passivation. Thaum kawg ntawm xyoo 1970, tus kws sau ntawv tau pom titanium ntsev nyiaj passivation cov khoom siv titanyl sulfate ua cov ntsev tseem ceeb, uas tsis yog tsuas yog muaj xim dawb xwb, tab sis kuj muaj kev tiv thaiv corrosion zoo; tab sis nws qhov tsis zoo yog los xyuas kom meej tias cov titanium ions nyob rau hauv lub xeev high-valence. Txhawm rau ntxiv ntau qhov tsis ruaj khov hydrogen peroxide, nws tsis tau nce qib.