Chrome plating txheej txheem cov yam ntxwv
Piv nrog rau lwm hom plating, chrome plating yog hom plating heev thiab muaj cov yam ntxwv hauv qab no:
(1) Chromium yog yooj yim passivated thiab yog li ruaj khov nyob rau hauv ntau yam xov xwm. Los ntawm cov qauv atomic, nws muaj cov yam ntxwv sib txawv piv nrog rau lwm cov hlau. Chromium yog cov hlau nquag heev. Thaum plating chromium nyob rau hauv chromic acid, ib txheej nruam yuav tsum tau txais ntawm lub peev xwm tsawg heev. Piv nrog rau cov txheej txheem electroplating ntawm lwm cov hlau, cov tshuaj tiv thaiv cathode ntawm chromium plating yog qhov nyuaj. Muaj cov deposition ntawm hlau chromium, tiam ntawm trivalent chromium, thiab ib tug loj npaum li cas ntawm hydrogen yog txo. Yog li ntawd, cov cathode tam sim no efficiency yog tsawg heev (10-18%). Cov tshuaj tiv thaiv electrode los ntawm chromate ions kom txo tau cov hlau chromium kuj yog qhov nyuaj heev. Txog rau tam sim no, nws cov txheej txheem nruab nrab yog qhov teeb meem ntawm kev sib cav. Tsis tas li ntawd, muaj qee qhov nyiaj ntawm Cr3+ hauv chromium plating electrolyte rau cov txheej txheem chromium plating kom paub.
(2) Qhov ceev tam sim no siv nyob rau hauv chromium plating yog siab heev, kaum ob lub sij hawm siab tshaj ntawm cov plating. Lub tank voltage thaum lub sij hawm chromium plating txheej txheem kuj yog siab heev, uas yog ob zaug siab li lub tank voltage (6V) ntawm lwm hom plating. Feem ntau nyob ib ncig ntawm 12V.
(3) Cov anode siv nyob rau hauv chromium plating tsis yog xim hlau chromium, tab sis lead + antimony los yog lead + tin alloy li anode insoluble. Qhov no yog vim cov hlau chromium yog nkig thiab yooj yim tawg, ua rau nws nyuaj rau ua rau cov nplooj ntawv. Tsis tas li ntawd, thaum hlau chromium dissolves, nws nkag mus rau hauv cov kev daws teeb meem hauv ntau lub xeev valence, uas yuav ua rau muaj kev hloov loj hauv cov tshuaj thiab ua rau nws nyuaj rau kev tswj. Yog li ntawd, insoluble anodes yog siv, thiab lub peev xwm dispersion ntawm cov tshuaj chromium plating yog tsawg heev. Rau complex-shaped plated qhov chaw, yuav tsum tau ib tug auxiliary anode kom tau ib tug txheej nrog uniform thickness.
(4) Thaum lub sij hawm chromium plating txheej txheem, tsis muaj hluav taws xob raug tso cai. Qhov kub thiab qhov tam sim no yuav tsum ruaj khov. Qhov sib txawv ntawm qhov ntau thiab tsawg thiab thickened chrome-plated qhov chaw yuav tsum tsis txhob nyob rau hauv tib lub tank. Tsis tas li ntawd, cov duab sib txawv ntawm qhov chaw yuav tsum muaj cov qauv sib txawv ntawm cov khoom dai, yog li kev saib xyuas yuav tsum tau them rau kev xaiv cov khoom dai.
(5) Txhawm rau kom ntseeg tau tias cov txheej txheem muaj lub zog sib txuas, cov khoom yuav tsum tau dai rau hauv lub tank plating lossis lub tank dej kub ua ntej ua ntej chromium plating, kom qhov kub ntawm qhov chaw thiab cov tshuaj plating zoo ib yam. Rau tooj liab thiab hniav chrome-plated qhov chaw, tsis txhob muab cov chromium qhov chaw rau hauv lub plating tank rau kev kho ua ntej. Kub, tuaj yeem preheated hauv dej kub.
(6) Rau qhov chaw nrog cov duab tsis yooj yim, txhawm rau txhim kho qhov sib sib zog nqus plating muaj peev xwm, thaum pib ua kom muaj zog, lub zog tam sim no tuaj yeem siv tau, uas yog, tam sim no tuaj yeem yog 50% -60% siab dua li qub. tam sim no yog siv, thiab cov impulse tam sim no yog thawj zaug thov rau 2-3 feeb thiab tom qab ntawd ntawm qhov qub tam sim no. Chrome plated raws li kev ua haujlwm tshwj xeeb.
(7) Cov txheej chromium yog microporous thaum nws yog 0.25 μm. Yog tias qhov tuab tshaj 0.25 μm, cov kab nrib pleb yuav tshwm sim hauv cov txheej chromium. Tsuas yog thaum lub thickness ntawm chromium txheej tshaj 20 μm nws yuav muaj kev tiv thaiv txhua yam ntawm cov substrate, thiab chromium txheej yuav muaj cov kab nrib pleb. Ib qho ntawm cov laj thawj yog vim li cas qhov ua rau micro-cracks nyob rau hauv txheej txheej ntawm high-stress npib tsib xee tau tham nyob rau hauv cov kev ntxhov siab nickel ib feem. Ntawm no, kev tshawb fawb tshwj xeeb thiab kev tshuaj xyuas ntawm chromium plating txheej yog xav tau. Qhov laj thawj yog vim li cas chromium tawg tshwm sim yog tias thaum lub sij hawm electrodeposition ntawm chromium, nws absorbs ib tug npaum li cas ntawm hydrogen los ua chromium hydride, thiab kuj absorbs ib co ntawm cov pa oxygen. Chromium hydride nrog hexagonal lattice qauv tsis ruaj khov heev. Nws decomposes tsim ib txheej chromium nrog lub cev-centered cubic lattice. Vim lub ntim shrinkage thaum lub sij hawm decomposition, chromium txheej muaj kev ntxhov siab sab hauv, thiab micropores los yog network tawg yog tsim nyob rau hauv chromium txheej.
Qhov tshwj xeeb ntawm chrome plating
Ntxiv rau cov yam ntxwv saum toj no, hauv cov txheej txheem chromium plating tiag tiag, ntxiv rau cov yam ntxwv ntawm lwm hom plating, tshwj xeeb yuav tsum tau them rau daim ntawv thov:
(1) Vim tias qhov muaj peev xwm tsis zoo ntawm cov txheej txheem plating, ua kom cov txheej txheej plating tsis zoo, nws yog ib qho tsim nyog los tsim tshwj xeeb hangers thiab fixtures (xws li ntxhw anodes) raws li cov duab geometric ntawm cov khoom plated. Lub workpiece dai txoj kev thiab rwb thaiv tsev txheej ntawm cov hangers yog txhua yam tseem ceeb heev.
(2) Nws yuav tsum tau muab sau tseg tias thaum lub sij hawm chromium plating txheej txheem, ib tug loj npaum li cas ntawm hydrogen yog generated nyob rau hauv cathode thiab ib tug loj npaum li cas ntawm cov pa yog generated ntawm lub anode. Yog tias cov cuab yeej tso pa tawm tsis zoo, cov pa hydrogen thiab oxygen yuav tawg, thiab ntau cov hydrogen thiab oxygen yuav raug tso tawm, nqa tawm cov tshuaj lom chromium pos huab thiab kua qaub. Cov cuab yeej siv hluav taws xob zoo tuaj yeem siv tau, thiab cov pos huab tuaj yeem raug ntxiv kom tsim nyog los tiv thaiv thiab txo cov pa phem los ntawm kev xav, thiab xyuam xim rau kev nyab xeeb ntawm kev tsim khoom.
(3) Txhawm rau kom tau txais cov txheej txheem chromium plating ruaj khov, chromium plating ntau lawm yuav tsum muaj qhov siab tam sim no, uas tsis tsuas yog yuav tsum muaj lub peev xwm loj ntawm tam sim no, tab sis kuj muaj peev xwm loj, ntawm qhov sib piv ntawm 1 ~ 1.2A ib liter ntawm plating tov. (lwm cov electroplating feem ntau yog 0.3-0.5A/L rau electroplating), cua txias yuav tsum tau thaum tsim nyog, thiab cov khoom siv tu yuav tsum tau them nyiaj mloog mus rau hauv kev tsim txhua hnub kom ntseeg tau tias cov khoom siv chromium plating zoo .
(4) Lub electrodeposition kev nyuaj siab ntawm chromium plating txheej yog loj. Yog tias nws nyias, nws yuav muaj qhov pores ntau dua, thiab yog tias nws tuab, nws yuav ua rau tawg. Yog li ntawd, peb yuav tsum ua tib zoo tswj qhov tsim nyog thickness ntawm lub plating txheej. Cov hniav chromium plating txheej feem ntau yog 0.1-0.5 μm, thiab lub sij hawm plating yog 1-4 feeb. Piv nrog rau lwm hom plating, lub sij hawm sai dua thiab cov txheej yog nyias. Vim nws tsis zoo dispersion thiab npog lub hwj chim, qhov chaw uas muaj tam sim no ceev ntawm qhov kawg ntawm ib co workpieces feem ntau plated thickly thiab cov kab nrib pleb tshwm sim, thaum lub sij hawm qhov chaw uas tsis tshua muaj tam sim no ceev xws li concave qhov chaw feem ntau tsis plated, yog li ntawd lub lag luam yuav tsum tau hloov tau.
Classification ntawm chrome plating
Chrome plating tuaj yeem muab faib ua ob pawg raws li nws siv thiab cov yam ntxwv ntawm chromium plating: ib qho yog kev tiv thaiv zoo nkauj chrome plating, feem ntau hu ua hniav chrome; Lwm qhov yog ua haujlwm chrome plating.
Thaum tiv thaiv cov hniav chrome plating, tooj liab, npib tsib xee, npib tsib xee-hlau alloy lossis tooj liab-tin alloy feem ntau yog siv los ua cov txheej txheem nruab nrab. Qhov saum npoo ntawm cov txheej nruab nrab ci ci yog tom qab ntawd plated nrog 0.2-0.5μm chromium los txhim kho qhov zoo nkauj, corrosion kuj thiab kev pab cuam lub neej ntawm cov khoom xws li cov khoom siv kho tshuab, cov khoom siv hluav taws xob, cov khoom siv kho mob, cov khoom siv kho mob. , thiab lwm yam. Ordinary chromium plating nrog cov tshuaj plating uas muaj sulfuric acid thiab chromic anhydride hauv kev tiv thaiv cov hniav chromium plating: Composite chromium plating nrog cov tshuaj plating uas muaj cov txheej txheem chromium plating cov yam ntxwv, kev faib tawm thiab siv raws li qhia hauv daim duab 2; Kev nrawm chromium plating los ntawm kev ntxiv ib qho nyiaj ntawm H3BO3 thiab MgO rau tus qauv chrome plating electrolyte Chrome plating; tsis siv neeg hloov ntawm chromium plating siv SrSO4 thiab K2SiF6 li catalysts rau chromium plating kua, nrog rau microcrack chromium, microporous chromium, tetrachromic acid thiab ntsev chromium plating; trivalent chromium plating, chim chromium plating, thiab lwm yam.
hais txog cov khoom hauv ehisen
