Sodium Cyanide Electroplating Zinc Txheej Txheem: Kev Ntsuas Kev Ntsuas

Introduction

Electroplating yog ib qho txheej txheem siv dav hauv ntau yam lag luam los txhim kho cov yam ntxwv ntawm cov hlau nto. Ntawm ntau txoj kev electroplating, Sodium Cyanide electroplating zinc tuav lub luag haujlwm tseem ceeb vim nws cov yam ntxwv tshwj xeeb thiab qhov zoo. Tsab xov xwm no lub hom phiaj yog los muab kev tshuaj xyuas ntxaws ntxaws ntawm Sodium cyanide electroplating zinc txheej txheem, npog nws cov hauv paus ntsiab lus, cov kauj ruam txheej txheem, cov khoom siv da dej, thiab kev txiav txim siab ua haujlwm.

Cov ntsiab lus ntawm Sodium Cyanide Electroplating Zinc

Hauv cov txheej txheem electroplating zinc sodium cyanide , lub hauv paus ntsiab lus tseem ceeb yog raws li electrolysis. Lub dab dej electroplating muaj cov zinc ions thiab lwm yam khoom. Thaum siv hluav taws xob, cov zinc ions hauv lub dab dej raug txo qis ntawm cathode (qhov khoom yuav tsum tau plated), thiab cov zinc atoms raug tso rau ntawm qhov chaw ntawm cathode, tsim cov zinc txheej. Qhov muaj Sodium cyanide hauv lub dab dej ua lub luag haujlwm tseem ceeb. Nws ua haujlwm ua tus neeg sawv cev complexing, tsim cov complexes ruaj khov nrog zinc ions. Qhov complexation no pab tswj cov nqi deposition ntawm zinc thiab txhim kho qhov zoo ntawm cov zinc txheej tso. Piv txwv li, qhov kev tshuaj tiv thaiv tuaj yeem sawv cev yooj yim li: Zn(CN)₄²⁻ + 2e⁻ → Zn + 4CN⁻ ntawm cathode. Cov complexed zinc ions hauv daim ntawv ntawm Zn(CN)₄²⁻ ruaj khov dua hauv lub dab dej, uas ua rau muaj cov zinc deposition sib npaug thiab zoo dua piv rau cov txheej txheem tsis-complexed.

Cov txheej txheem

1. Pretreatment ntawm substrate

Ua ntej electroplating, lub substrate (cov khoom hlau yuav tsum tau plated) yuav tsum tau pretreated kom huv si. Cov kauj ruam no yog qhov tseem ceeb los xyuas kom zoo adhesion ntawm zinc txheej.

• Kev Tshem Tawm Cov Roj : Lub substrate raug tshem tawm cov roj, roj, lossis cov organic contaminants ntawm nws qhov chaw. Qhov no tuaj yeem ua tiav los ntawm cov txheej txheem xws li alkaline degreasing, qhov twg lub substrate raug muab tso rau hauv cov kua alkaline uas muaj surfactants. Cov kua alkaline reacts nrog cov roj, emulsifying nws thiab cia nws raug ntxuav tawm. Piv txwv li, cov kua alkaline degreasing feem ntau yuav muaj sodium hydroxide, sodium Carbonate , thiab surfactants xws li sodium dodecyl sulfate.

• Kev Tua Kab : Tom qab tshem cov roj, kev tua kab yog ua kom tshem tawm cov xeb, oxides, thiab lwm yam inorganic impurities ntawm qhov chaw substrate. Cov kua qaub, xws li hydrochloric acid lossis sulfuric acid, feem ntau yog siv rau kev tua kab. Cov kua qaub reacts nrog cov oxides ntawm qhov chaw, yaj lawv. Piv txwv li, nyob rau hauv cov ntaub ntawv ntawm xeb (hlau oxide) ntawm cov hlau substrate, qhov kev cuam tshuam nrog hydrochloric acid yog: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O. Tom qab tua kab, lub substrate yog rinsed kom huv si nrog dej kom tshem tawm cov kua qaub seem.

2. Kev npaj lub da dej Electroplating

Kev npaj lub dab dej electroplating yog ib kauj ruam tseem ceeb hauv cov txheej txheem sodium cyanide electroplating zinc.

• Cov Khoom Xyaw : Cov khoom tseem ceeb ntawm lub dab da dej muaj xws li zinc oxide (ZnO) ua qhov chaw ntawm zinc ions, sodium cyanide (NaCN) ua tus neeg sawv cev sib xyaw, thiab sodium hydroxide (NaOH) ua ntsev conductive. Tsis tas li ntawd, lwm yam khoom ntxiv yuav raug suav nrog los txhim kho qhov zoo ntawm cov plating, xws li cov khoom ci ntsa iab. Rau lub dab da dej electroplating qis cyanide, cov khoom sib xyaw yuav yog: ZnO 8 - 12 g/L, NaCN 10 - 20 g/L, NaOH 80 - 120 g/L.

• Cov Txheej Txheem Sib Tov : Ua ntej, ib feem ntawm cov dej (kwv yees li ib feem peb ntawm tag nrho cov ntim dej da dej) raug ntxiv rau hauv lub tank plating. Tom qab ntawd, qhov ntau ntawm sodium cyanide thiab sodium hydroxide uas xav tau raug ntxiv thiab do kom txog thaum yaj tag. Tom ntej no, zinc oxide raug ntxiv maj mam rau hauv cov tshuaj thaum lub sijhawm do tas li. Zinc oxide cuam tshuam nrog sodium hydroxide thiab sodium cyanide los tsim cov tshuaj sib xyaw tsim nyog. Tom qab ntxiv zinc oxide, lub da dej raug diluted mus rau qhov ntim xav tau nrog dej. Thaum kawg, cov khoom ntxiv raug ntxiv raws li cov lus qhia ntawm cov chaw tsim khoom.

3. Cov txheej txheem electroplating

• Kev Teeb tsa Lub Cell Electroplating : Lub cell electroplating muaj lub plating bath, lub cathode (lub substrate uas yuav tsum tau plated), thiab lub anode. Lub anode feem ntau yog ua los ntawm cov hlau zinc. Thaum cov hluav taws xob raug hla dhau lub bath, cov zinc ions raug yaj los ntawm lub anode mus rau hauv lub bath thiab tib lub sijhawm tso rau ntawm cathode. Qhov ceev tam sim no, uas yog qhov ntau ntawm cov tam sim no ib cheeb tsam ntawm cathode, raug tswj hwm zoo. Rau sodium cyanide electroplating zinc, qhov ceev tam sim no feem ntau yog txij li 1 - 5 A/dm². Qhov ceev tam sim no qis dua yuav ua rau qhov nrawm qeeb dua tab sis tuaj yeem ua rau muaj cov txheej txheej sib npaug thiab zoo dua. Ntawm qhov tod tes, qhov ceev tam sim no siab dua tuaj yeem ua rau qhov nrawm tso tawm ntau dua tab sis yuav ua rau muaj teeb meem xws li kev plating tsis sib xws thiab hlawv ntawm cov txheej txheej ntawm cov cheeb tsam siab.

• Kub thiab Kev Ntxhov Siab : Qhov kub ntawm lub dab dej electroplating kuj cuam tshuam rau cov txheej txheem plating. Feem ntau, qhov kub ntawm lub dab dej yog tswj nyob rau hauv qhov ntau ntawm 20 - 40 ° C. Qhov kub siab dua tuaj yeem ua rau kom muaj kev tso tawm ntau ntxiv tab sis kuj tseem yuav txo qhov cathode polarization, ua rau muaj txheej txheej coarser. Kev ntxhov siab ntawm lub dab dej yog qhov tseem ceeb kom ntseeg tau tias muaj kev faib tawm ntawm cov ions nyob ib puag ncig cathode. Qhov no tuaj yeem ua tiav los ntawm kev ntxhov siab, xws li siv lub stirrer, lossis los ntawm cua npuas. Kev ntxhov siab pab rov ua kom cov zinc ions nyob ze ntawm qhov chaw cathode, tiv thaiv kev tsim cov concentration gradients uas tuaj yeem ua rau tsis sib xws plating.

4. Post - kev kho mob

• Kev Ntxuav : Tom qab electroplating, cov khoom plated raug ntxuav kom huv si nrog dej kom tshem tawm cov tshuaj plating seem ntawm nws qhov chaw. Tej zaum yuav ua tau ntau kauj ruam ntxuav, nrog rau thawj zaug ntxuav hauv dej txias kom tshem tawm feem ntau ntawm cov tshuaj, tom qab ntawd yaug ntxiv hauv dej huv kom ntseeg tau tias tshem tawm tag nrho cov kuab paug.

• Chromating : Chromating feem ntau yog ua los txhim kho qhov kev tiv thaiv xeb ntawm cov txheej zinc-plated. Cov khoom plated raug muab tso rau hauv cov kua chromating, uas muaj chromic acid lossis nws cov ntsev. Cov txheej txheem chromating tsim ib txheej nyias, tiv thaiv chromate hloov pauv ntawm qhov chaw ntawm cov txheej zinc. Cov txheej txheem no muab kev tiv thaiv ntxiv tiv thaiv xeb los ntawm kev ua haujlwm ua ib qho kev thaiv thiab kuj los ntawm kev kho tus kheej rau qee qhov thaum qhov chaw raug khawb. Muaj ntau hom chromating, xws li daj chromating, xiav - dawb chromating, thiab dub chromating, txhua tus muab ntau qib ntawm kev tiv thaiv xeb thiab kev zoo nkauj.

• Kev Qhuav : Thaum kawg, cov khoom plated thiab chromated raug ziab. Rau cov khoom me me, lawv tuaj yeem ziab hauv lub tshuab ziab centrifugal nrog cua kub, thaum cov khoom loj dua tuaj yeem ziab cua ntawm chav tsev kub. Kev ziab yog qhov tseem ceeb kom tiv thaiv kev tsim cov dej thiab kom ntseeg tau tias lub txheej ruaj khov mus sij hawm ntev.

Bath Composition thiab Nws Influence

1. Zinc Oxide (ZnO)

Zinc oxide yog lub hauv paus ntawm zinc ions hauv electroplating da dej. Qhov concentration ntawm zinc oxide nyob rau hauv da dej cuam tshuam rau tus nqi deposition ntawm zinc. Qhov ntau dua ntawm zinc oxide feem ntau ua rau muaj kev tso nyiaj ntau dua. Txawm li cas los xij, yog tias zinc ion concentration siab dhau lawm, nws tuaj yeem ua rau muaj teeb meem xws li lub zog pov tseg tsis zoo (lub peev xwm ntawm cov tshuaj plating kom tso cov txheej txheem sib xws ntawm cov khoom sib xws) thiab coarser - grained txheej. Hauv cov da dej uas tsis tshua muaj cyanide, qhov tsim nyog zinc oxide concentration feem ntau yog nyob rau hauv ntau yam tau hais ua ntej (8 - 12 g / L), uas muab qhov sib npaug ntawm qhov tso nyiaj thiab txheej txheej zoo.

2. Sodium Cyanide (NaCN)

Sodium cyanide ua haujlwm ua tus neeg sawv cev hauv chav da dej. Nws tsim complexes nrog zinc ions, xws li Zn (CN) ₄²⁻. Qhov concentration ntawm sodium cyanide cuam tshuam rau kev ruaj ntseg ntawm cov complexes thiab, yog li ntawd, tus cwj pwm deposition ntawm zinc. Nyob rau hauv high - cyanide da dej, ib tug kuj siab concentration ntawm sodium cyanide yog siv, uas muab zoo heev pov hwj chim thiab ib tug zoo heev - grained txheej. Txawm li cas los xij, high-cyanide da dej ua rau muaj kev pheej hmoo loj ntawm ib puag ncig thiab kev nyab xeeb vim muaj tshuaj lom ntawm cyanide. Nyob rau hauv sib piv, tsawg - cyanide da dej, uas yog siv ntau niaj hnub no, siv ib tug qis concentration ntawm sodium cyanide (piv txwv li, 10 - 20 g / L). Cov chav da dej no tseem muaj lub zog pov tseg zoo thiab txheej txheej zoo thaum txo cov kev txhawj xeeb ntawm ib puag ncig thiab kev nyab xeeb rau qee qhov. Qhov piv ntawm sodium cyanide rau zinc oxide (NaCN / ZnO piv) kuj ua lub luag haujlwm tseem ceeb. Ib qho piv txwv tsim nyog ua kom cov tsim ntawm cov complexes ruaj khov thiab zoo plating tej yam kev mob. Piv txwv li, hauv qee daim ntawv thov, NaCN / ZnO piv ntawm ib ncig ntawm 1.5 - 2.5 yog nyiam.

3. Sodium Hydroxide (NaOH)

Sodium hydroxide ua raws li cov ntsev conductive hauv da dej, ua kom cov hluav taws xob conductivity ntawm cov tshuaj. Qhov no tso cai rau kom muaj txiaj ntsig zoo dua ntawm kev hloov pauv tam sim no thaum electroplating. Nws kuj pab tswj cov pH ntawm da dej. Lub pH ntawm sodium cyanide electroplating zinc da dej yog feem ntau nyob rau hauv alkaline ntau, nyob ib ncig ntawm pH 12 - 14. Ib qho pH ruaj khov yog qhov tseem ceeb rau kev ruaj ntseg ntawm cov complexes thiab tag nrho cov txheej txheem plating. Yog tias pH tsawg dhau, cov complexes yuav decompose, ua rau cov plating tsis zoo. Ntawm qhov tod tes, yog tias pH siab dhau lawm, nws tuaj yeem ua rau muaj teeb meem xws li kev xeb ntau dhau ntawm cov anode thiab tsim cov zinc hydroxide precipitates hauv da dej.

4. Cov tshuaj ntxiv

• Cov Tshuaj Ci Ntxim : Cov tshuaj ci ntsa iab raug ntxiv rau hauv lub dab da dej kom txhim kho qhov ci ntsa iab thiab ci ntsa iab ntawm cov txheej zinc. Lawv ua haujlwm los ntawm kev hloov kho qhov morphology ntawm qhov chaw ntawm cov txheej zinc uas tau tso rau ntawm qib atomic. Cov organic compounds xws li saccharin, coumarin, thiab qee cov ntsev quaternary ammonium feem ntau yog siv los ua cov tshuaj ci ntsa iab. Piv txwv li, saccharin tuaj yeem nqus tau rau ntawm qhov chaw ntawm cathode thaum lub sijhawm electroplating, txwv tsis pub cov zinc crystals loj hlob hauv qee qhov kev taw qhia thiab txhawb kev tsim ntawm qhov chaw du thiab ci ntsa iab.

• Cov Khoom Siv Qib : Cov khoom siv qib pab ua kom du cov qhov tsis sib xws ntawm qhov chaw ntawm lub substrate thaum lub sijhawm electroplating. Lawv feem ntau tso rau ntawm thaj chaw siab dua ntawm lub substrate, txo qhov sib txawv ntawm cov tuab ntawm thaj chaw siab thiab qis dua thiab ua rau muaj txheej txheej sib xws dua. Qee cov polymers thiab surfactants tuaj yeem ua haujlwm ua cov khoom qib hauv lub dab dej electroplating.

• Cov Tshuaj Antioxidants thiab Stabilizers : Cov tshuaj ntxiv no yog siv los tiv thaiv kev oxidation ntawm cov khoom hauv lub dab da dej, tshwj xeeb tshaj yog cov cyanide ions. Cyanide tuaj yeem raug oxidized nyob rau hauv qhov muaj huab cua thiab qee yam impurities, uas tuaj yeem ua rau txo qis kev ua haujlwm ntawm tus neeg sawv cev complexing thiab kev hloov pauv hauv cov tshuaj lom neeg hauv lub dab da dej. Cov tshuaj antioxidants xws li sodium sulfite tuaj yeem ntxiv rau hauv lub dab da dej kom tshem tawm cov pa oxygen thiab tiv thaiv kev oxidation ntawm cyanide. Cov tshuaj stabilizers kuj tseem raug ntxiv los tswj kev ruaj khov ntawm lub dab da dej dhau sijhawm, kom ntseeg tau tias cov txiaj ntsig plating sib xws.

Kev Xav Txog Kev Ua Haujlwm

1. Ceev Faj Txog Kev Nyab Xeeb

Txij li thaum sodium cyanide yog tshuaj lom heev, yuav tsum tau ceev faj txog kev nyab xeeb thaum tuav thiab ua haujlwm ntawm cov txheej txheem electroplating. Txhua tus neeg ua haujlwm koom nrog hauv cov txheej txheem yuav tsum hnav cov khoom tiv thaiv tus kheej tsim nyog, suav nrog hnab looj tes, tsom iav, thiab lub tshuab ua pa. Electroplating cheeb tsam yuav tsum zoo-ventilated los tiv thaiv cov tsub zuj zuj ntawm cov pa phem. Nyob rau hauv rooj plaub uas muaj dej nchuav los yog xwm txheej cuam tshuam nrog sodium cyanide, yuav tsum tau ua raws li cov txheej txheem thaum muaj xwm txheej ceev. Qhov no tej zaum yuav muaj xws li neutralizing cov cyanide nrog cov tshuaj tsim nyog (xws li cov tshuaj hypochlorite) thiab ceeb toom rau cov neeg saib xyuas kev nyab xeeb.

2. Kev tu da dej

• Kev Tshuaj Xyuas Tsis Tu Ncua : Cov khoom sib xyaw ntawm lub dab da dej electroplating yuav tsum tau tshuaj xyuas tsis tu ncua kom ntseeg tau tias qhov concentration ntawm zinc oxide, sodium cyanide, sodium hydroxide, thiab cov additives nyob rau hauv qhov ntau zoo tshaj plaws. Cov txheej txheem tshuaj xyuas xws li titration tuaj yeem siv los txiav txim siab qhov concentration ntawm cov khoom no. Piv txwv li, qhov concentration ntawm zinc ions tuaj yeem txiav txim siab los ntawm titrating ib qho piv txwv ntawm lub dab da dej nrog tus qauv EDTA (ethylenediaminetetraacetic acid) kua.

• Kev Tswj Xyuas Kev Ua Phem : Kev ua phem ntawm lub dab da dej tuaj yeem tshwm sim los ntawm ntau qhov chaw, xws li cov khoom tsis huv hauv cov khoom siv raw, cov khoom txawv teb chaws los ntawm lub substrate thaum lub sijhawm plating, thiab kev tsim cov khoom cuam tshuam. Txhawm rau tswj kev ua phem, kev lim dej kom zoo ntawm lub dab da dej yuav tsum tau ua. Lub kaw lus lim dej nrog cov khoom lim dej kom zoo tuaj yeem tshem tawm cov khoom khov thiab qee cov organic contaminations. Tsis tas li ntawd, kev ntxuav lub dab da dej tsis tu ncua yuav tsum tau ua. Piv txwv li, yog tias cov hlau hnyav impurities (xws li tooj liab lossis txhuas) sib sau ua ke hauv lub dab da dej, lawv tuaj yeem raug tshem tawm los ntawm kev ntxiv cov tshuaj uas tsim cov precipitates nrog cov impurities no, ua raws li kev lim dej.

• Kev Rov Ua Dua Cov Cheebtsam : Thaum cov txheej txheem electroplating txuas ntxiv mus, cov khoom hauv lub dab da dej raug siv tag. Zinc raug tso rau ntawm cathode, thiab qee cov neeg sawv cev ua ke thiab cov khoom ntxiv yuav raug rhuav tshem lossis siv rau hauv cov tshuaj tiv thaiv sab. Yog li ntawd, kev rov ua dua tsis tu ncua ntawm zinc oxide, sodium cyanide, sodium hydroxide, thiab cov khoom ntxiv yog qhov yuav tsum tau ua kom cov khoom hauv lub dab da dej muaj pes tsawg leeg. Tus nqi ntawm kev rov ua dua tuaj yeem txiav txim siab raws li lub sijhawm plating, qhov ntau ntawm cov khoom raug plated, thiab cov txiaj ntsig ntawm kev tshuaj xyuas da dej.

3. Kev daws teeb meem

• Kev Nplaum Tsis Zoo Rau Txheej : Yog tias txheej zinc tsis nplaum zoo rau cov khoom siv hauv pem teb, tej zaum yuav muaj xws li kev kho ua ntej tsis zoo ntawm cov khoom siv hauv pem teb, cov khoom siv hauv da dej tsis zoo (xws li pH tsis raug lossis cov tshuaj complexing tsawg), lossis cov khoom ua qias tuaj ntau hauv da dej. Txhawm rau daws qhov teeb meem no, cov txheej txheem ua ntej yuav tsum tau saib xyuas thiab ua kom zoo dua. Cov khoom siv hauv da dej yuav tsum tau soj ntsuam thiab kho yog tias tsim nyog, thiab yuav tsum tau ua cov kauj ruam los txo cov khoom ua qias tuaj.

• Kev Sib Tov Tsis Sib Luag : Kev sib tov tsis sib luag tuaj yeem tshwm sim los ntawm cov yam xws li kev faib hluav taws xob tsis raug hauv lub cell electroplating, kev sib xyaw tsis sib xws ntawm lub dab dej, lossis kev hloov pauv hauv cov qauv ntawm lub substrate. Txhawm rau daws qhov teeb meem no, kev teeb tsa lub cell electroplating tuaj yeem hloov kho kom ntseeg tau tias muaj kev faib hluav taws xob sib npaug ntau dua. Txoj kev sib xyaw tuaj yeem ua kom zoo dua, thiab cov khoom siv tuaj yeem tsim los tuav lub substrate hauv txoj hauv kev uas txhawb nqa kev sib xyaw sib xws. Rau cov substrates uas muaj cov duab sib txawv, cov txheej txheem plating tshwj xeeb lossis kev siv cov anodes pabcuam yuav tsum tau ua.

• Txheej Txheem Dub Los Yog Tsaus Ntuj : Txheej txheem zinc dub los yog tsaus ntuj tej zaum yuav yog vim muaj cov tshuaj pleev kom ci ntsa iab tsis txaus hauv lub dab da dej, muaj cov khoom tsis huv ntau dhau, lossis cov txheej txheem plating tsis raug (xws li qhov ceev tam sim no lossis qhov kub ntawm lub dab da dej siab dhau). Yuav tsum kuaj xyuas thiab kho qhov concentration ntawm cov tshuaj pleev kom ci ntsa iab yog tias xav tau. Lub dab da dej yuav tsum tau ntxuav kom huv si kom tshem tawm cov khoom tsis huv, thiab cov txheej txheem plating yuav tsum tau ua kom zoo.

xaus

Cov txheej txheem sodium cyanide electroplating zinc yog ib qho kev siv dav thiab tseem ceeb rau kev muab kev tiv thaiv corrosion thiab kho kom zoo nkauj tiav rau cov khoom hlau. Nkag siab txog nws cov ntsiab cai, txheej txheem txheej txheem, da dej muaj pes tsawg leeg, thiab kev txiav txim siab ua haujlwm yog qhov tseem ceeb rau kev ua tiav cov txiaj ntsig zoo plating. Txawm hais tias nws muaj qee qhov kev sib tw ntawm ib puag ncig thiab kev nyab xeeb cuam tshuam nrog kev siv sodium cyanide, nrog rau kev ntsuas kev nyab xeeb thiab kev txhim kho ntau yam kev nyab xeeb ntawm ib puag ncig (xws li qis - cyanide lossis cyanide - cov txheej txheem dawb), nws tseem ua lub luag haujlwm tseem ceeb hauv ntau yam lag luam, suav nrog tsheb, aerospace, thiab electronics. Los ntawm kev ua tib zoo tswj txhua yam ntawm cov txheej txheem, cov tuam ntxhab tuaj yeem tsim cov khoom siv zinc-plated nrog cov khoom zoo thiab kev ua haujlwm zoo.