Sodium Cyanide Electroplating Zinc Txheej Txheem: Kev Ntsuas Kev Ntsuas

Introduction

Electroplating yog txheej txheem siv dav hauv ntau qhov kev lag luam los txhim kho cov khoom ntawm cov hlau nto. Ntawm cov txheej txheem electroplating sib txawv, Sodium Cyanide electroplating zinc tuav txoj haujlwm tseem ceeb vim nws cov yam ntxwv tshwj xeeb thiab qhov zoo. Kab lus no aims muab cov ncauj lus kom ntxaws tsom xam ntawm cov Sodium cyanide electroplating zinc txheej txheem, npog nws cov hauv paus ntsiab lus, txheej txheem txheej txheem, da dej muaj pes tsawg leeg, thiab kev txiav txim siab ua haujlwm.

Cov ntsiab lus ntawm Sodium Cyanide Electroplating Zinc

Nyob rau hauv lub sodium cyanide electroplating zinc txheej txheem, lub hauv paus ntsiab lus tseem ceeb yog raws li electrolysis. Electroplating da dej muaj zinc ions thiab lwm yam khoom. Thaum siv hluav taws xob tam sim no, zinc ions hauv da dej raug txo qis ntawm cathode (cov khoom yuav tsum tau plated), thiab zinc atoms tau muab tso rau ntawm qhov chaw ntawm cathode, tsim cov zinc txheej. Lub xub ntiag ntawm Sodium cyanide hauv da dej plays lub luag haujlwm tseem ceeb. Nws ua raws li tus neeg sawv cev complexing, tsim cov complexes ruaj khov nrog zinc ions. Qhov no complexation pab tswj cov deposition tus nqi ntawm zinc thiab txhim kho qhov zoo ntawm deposited zinc txheej. Piv txwv li, cov tshuaj tiv thaiv tuaj yeem sawv cev tsuas yog: Zn(CN)₄²⁻ + 2e⁻ → Zn + 4CN⁻ ntawm cathode. Lub complexed zinc ions nyob rau hauv daim ntawv ntawm Zn (CN) ₄²⁻ yog ruaj khov nyob rau hauv da dej, uas ua rau ib tug ntau uniform thiab nplua-grained zinc deposition piv rau cov uas tsis yog-complexed systems.

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.

• NtsigUa ntej, cov substrate raug degreased kom tshem tawm cov roj, roj, lossis cov organic impurities ntawm nws qhov chaw. Qhov no tuaj yeem ua tiav los ntawm cov txheej txheem xws li alkaline degreasing, qhov twg cov 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 ib txwm muaj peev xwm muaj sodium hydroxide, sodium carboncov tshuaj surfactants xws li sodium dodecyl sulfate kuj tseem siv tau.

• Pickling: Tom qab degreasing, pickling yog nqa tawm kom tshem tawm xeb, oxides, thiab lwm yam inorganic impurities los ntawm substrate nto. Cov kua qaub, xws li hydrochloric acid lossis sulfuric acid, feem ntau yog siv rau pickling. Cov kua qaub reacts nrog oxides ntawm qhov chaw, dissolving lawv. Piv txwv li, nyob rau hauv cov ntaub ntawv ntawm xeb (hlau oxide) ntawm ib tug steel substrate, cov tshuaj tiv thaiv nrog hydrochloric acid yog: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O. Tom qab pickling, lub substrate yog rinsed kom huv si nrog dej kom tshem tawm tag nrho cov acids.

2. Kev npaj lub da dej Electroplating

Kev npaj ntawm da dej electroplating yog ib kauj ruam tseem ceeb hauv sodium cyanide electroplating zinc txheej txheem.

• Cov khoom xyaw: Cov khoom tseem ceeb ntawm cov da dej muaj xws li zinc oxide (ZnO) ua lub hauv paus ntawm zinc ions, sodium cyanide (NaCN) ua tus neeg sawv cev complexing, thiab sodium hydroxide (NaOH) ua cov ntsev ntsev. Tsis tas li ntawd, lwm yam khoom siv ntxiv tuaj yeem suav nrog txhawm rau txhim kho qhov zoo ntawm cov plating, xws li brighteners. Rau ib qho qis-cyanide electroplating da dej, muaj pes tsawg leeg yuav yog: ZnO 8 - 12 g / L, NaCN 10 - 20 g / L, NaOH 80 - 120 g / L.

• Kev sib tov: Ua ntej, ib feem ntawm cov dej (kwv yees li ib feem peb ntawm tag nrho cov da dej ntim) yog ntxiv rau lub plating tank. Tom qab ntawd, qhov xav tau ntawm sodium cyanide thiab sodium hydroxide yog ntxiv thiab nplawm kom txog thaum yaj tag. Tom ntej no, zinc oxide maj mam ntxiv rau cov tshuaj thaum tsis tu ncua stirring. Zinc oxide reacts nrog sodium hydroxide thiab sodium cyanide los tsim cov complexes tsim nyog. Tom qab ntxiv zinc oxide, da dej yog diluted mus rau qhov xav tau ntim nrog dej. Thaum kawg, cov tshuaj ntxiv tau ntxiv raws li cov neeg tsim khoom cov lus qhia.

3. Cov txheej txheem electroplating

• Kev teeb tsa Electroplating Cell: Lub xov tooj ntawm tes electroplating muaj cov plating da dej, cathode (lub substrate yuav tsum plated), thiab anode. Lub anode feem ntau yog ua los ntawm zinc hlau. Thaum cov hluav taws xob tam sim no dhau los ntawm lub da dej, zinc ions yog yaj los ntawm anode mus rau hauv da dej thiab ib txhij tso rau ntawm cathode. Qhov ceev tam sim no, uas yog tus nqi tam sim no ntawm ib cheeb tsam ntawm cathode, ua tib zoo tswj. Rau sodium cyanide electroplating zinc, qhov tam sim no ntom ntom ntawm 1 - 5 A / dm². Qhov qis dua tam sim no yuav ua rau qeeb qeeb qeeb tab sis tuaj yeem ua rau muaj qhov sib xws thiab zoo dua - grained txheej. Ntawm qhov tod tes, qhov ceev tam sim no ntau dua tuaj yeem ua rau nce tus nqi deposition tab sis yuav ua rau muaj teeb meem xws li plating tsis sib xws thiab kub kub ntawm cov txheej txheem ntawm qhov siab - tam sim no.

• Kub thiab txias: Qhov kub ntawm lub da dej electroplating kuj cuam tshuam rau cov txheej txheem plating. Feem ntau, da dej kub yog khaws cia nyob rau hauv thaj tsam ntawm 20 - 40 ° C. Kev kub siab dua tuaj yeem ua rau nce tus nqi deposition tab sis kuj tseem tuaj yeem txo cov cathode polarization, ua rau coarser - grained txheej. Agitation ntawm da dej yog ib qho tseem ceeb kom ntseeg tau tias kev sib faib ntawm ions nyob ib ncig ntawm lub cathode. Qhov no tuaj yeem ua tiav los ntawm kev ua kom muaj zog, xws li siv lub tshuab ua kom sov, lossis los ntawm huab cua bubbling. Agitation pab ntxiv cov zinc ions nyob ze ntawm lub cathode nto, tiv thaiv kev tsim cov concentration gradients uas tuaj yeem ua rau tsis sib xws.

4. Post - kev kho mob

• Rinsing: Tom qab electroplating, cov khoom plated yog rinsed kom huv si nrog dej kom tshem tawm cov residual plating tov ntawm nws nto. Ntau cov kauj ruam yaug tuaj yeem ua tiav, nrog rau thawj zaug yaug hauv dej txias kom tshem tawm cov tshuaj ntau, ua raws li cov dej huv ntxiv kom tshem tawm tag nrho cov kab mob.

• Chromating: Chromating feem ntau ua los txhim kho corrosion kuj ntawm zinc-plated txheej. Cov khoom plated yog raus rau hauv cov tshuaj chromating, uas muaj chromic acid los yog nws cov ntsev. Cov txheej txheem chromating tsim ib txheej nyias, tiv thaiv chromate hloov dua siab tshiab rau saum npoo ntawm zinc txheej. Cov txheej no muab kev tiv thaiv ntxiv tiv thaiv corrosion los ntawm kev ua raws li ib qho kev thaiv thiab kuj los ntawm nws tus kheej - kho rau qee yam thaum nto khawb. Muaj ntau hom chromating, xws li daj chromating, xiav - dawb chromating, thiab dub chromating, txhua tus muab ntau theem ntawm corrosion kuj thiab zoo nkauj tsos.

• Kom qhuav: Thaum kawg, cov khoom plated thiab chromated yog qhuav. Rau qhov me me, lawv tuaj yeem qhuav hauv lub tshuab ziab khaub ncaws centrifugal nrog cua kub, thaum qhov loj dua tuaj yeem yog cua - qhuav ntawm chav tsev kub. Kev ziab yog qhov tseem ceeb los tiv thaiv kev tsim cov dej me me thiab ua kom lub sij hawm ntev ntawm cov txheej txheej.

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

• Brighteners: Brighteners tau ntxiv rau hauv da dej los txhim kho lub ci ci thiab luster ntawm zinc txheej. Lawv ua haujlwm los ntawm kev hloov kho qhov chaw morphology ntawm cov txheej zinc deposited ntawm qib atomic. Organic compounds xws li saccharin, coumarin, thiab qee yam quaternary ammonium ntsev feem ntau yog siv los ua cov ci ci. Piv txwv li, saccharin tuaj yeem adsorb rau ntawm qhov chaw ntawm cathode thaum lub sij hawm electroplating, inhibiting kev loj hlob ntawm zinc crystals nyob rau hauv tej yam kev qhia thiab txhawb kev tsim ntawm ib tug du thiab ci nto.

• Qib: Levelers pab kom du tawm tej yam tsis xws luag ntawm lub substrate nto thaum electroplating. Lawv nyiam tso rau ntawm qhov siab dua - tam sim no - qhov ntom ntom ntawm cov substrate, txo cov thickness sib txawv ntawm qhov siab - thiab qis - tam sim no - qhov ntom ntom thiab ua rau cov txheej txheem ntau dua. Qee cov polymers thiab surfactants tuaj yeem ua haujlwm raws li cov qib hauv cov da dej electroplating.

• Antioxidants thiab Stabilizers: Cov tshuaj ntxiv no yog siv los tiv thaiv oxidation ntawm cov khoom hauv da dej, tshwj xeeb tshaj yog cov cyanide ions. Cyanide tuaj yeem oxidized nyob rau hauv lub xub ntiag ntawm huab cua thiab qee yam impurities, uas tuaj yeem ua rau txo qis hauv kev ua haujlwm ntawm tus neeg sawv cev complexing thiab hloov pauv hauv chav da dej chemistry. Antioxidants xws li sodium sulfite tuaj yeem muab ntxiv rau hauv da dej kom tshem tawm cov pa oxygen thiab tiv thaiv oxidation ntawm cyanide. Stabilizers kuj tseem ntxiv kom muaj kev ruaj ntseg ntawm lub da dej thaum lub sij hawm, kom ntseeg tau tias cov txiaj ntsig zoo 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 soj ntsuam tsis tu ncua: Cov muaj pes tsawg leeg ntawm electroplating da dej yuav tsum tau soj ntsuam tsis tu ncua kom ntseeg tau tias cov concentrations ntawm zinc oxide, sodium cyanide, sodium hydroxide, thiab additives nyob rau hauv qhov kev pom zoo. analytical txoj kev xws li titration tuaj yeem siv los txiav txim siab cov ntsiab lus ntawm cov khoom no. Piv txwv li, qhov concentration ntawm zinc ions tuaj yeem txiav txim siab los ntawm titrating tus qauv ntawm da dej nrog tus qauv EDTA (ethylenediaminetetraacetic acid) tov.

• Kev Tiv Thaiv Kab Mob: Kev sib kis ntawm cov da dej tuaj yeem tshwm sim los ntawm ntau qhov chaw, xws li impurities nyob rau hauv cov ntaub ntawv raw, 带入 ntawm cov khoom txawv teb chaws los ntawm lub substrate thaum lub sij hawm plating, thiab lub build-up ntawm cov tshuaj tiv thaiv los ntawm cov khoom. Txhawm rau tswj kev sib kis, kev lim dej kom zoo yuav tsum tau ua. Lub tshuab lim nrog cov khoom lim tsim nyog tuaj yeem tshem tawm cov khoom siv thiab qee cov kab mob organic. Tsis tas li ntawd, lub sijhawm ua kom huv ntawm lub da dej yuav tsim nyog. Piv txwv li, yog hais tias hnyav hlau impurities (xws li tooj liab los yog txhuas) nyob rau hauv lub da dej, lawv tuaj yeem raug tshem tawm los ntawm kev ntxiv cov tshuaj uas ua rau precipitates nrog cov impurities, ua raws li kev pom.

• Replenishment ntawm Cheebtsam: Raws li cov txheej txheem electroplating pib, cov khoom hauv da dej tau noj. Zinc yog tso rau ntawm cathode, thiab qee cov tshuaj complexing thiab additives tej zaum yuav decomposed los yog noj nyob rau hauv cov tshuaj tiv thaiv. Yog li ntawd, tsis tu ncua ntxiv ntawm zinc oxide, sodium cyanide, sodium hydroxide, thiab additives yuav tsum tau ua kom lub da dej muaj pes tsawg leeg. Tus nqi ntawm cov khoom ntxiv tuaj yeem txiav txim siab raws li lub sijhawm plating, tus nqi ntawm cov khoom raug plated, thiab cov txiaj ntsig ntawm kev tshuaj xyuas da dej.

3. Kev daws teeb meem

• Cov txheej txheem tsis zoo: Yog hais tias cov zinc txheej tsis zoo adhesion rau lub substrate, tej zaum yuav muaj xws li tsis txaus pretreatment ntawm lub substrate, da dej tsis zoo muaj pes tsawg leeg (xws li pH tsis raug los yog tsawg complexing tus neeg saib xyuas concentration), los yog muaj cov kab mob nyob rau hauv lub da dej. Txhawm rau daws qhov teeb meem no, cov txheej txheem ua ntej yuav tsum tau tshuaj xyuas thiab kho kom zoo. Lub da dej muaj pes tsawg leeg yuav tsum tau soj ntsuam thiab kho yog tias tsim nyog, thiab cov kauj ruam yuav tsum tau ua kom txo tau cov kab mob.

• Tsis sib npaug Plating: Cov plating tsis sib xws tuaj yeem tshwm sim los ntawm cov yam ntxwv xws li kev faib tawm tam sim no tsis zoo hauv lub xov tooj ntawm tes electroplating, tsis muaj kev ntxhov siab ntawm chav da dej, lossis kev hloov pauv hauv cov geometry ntawm lub substrate. Txhawm rau daws qhov teeb meem no, lub teeb tsa hluav taws xob electroplating tuaj yeem hloov kho kom ntseeg tau tias muaj kev faib tawm ntau dua tam sim no. Txoj kev ntxhov siab tuaj yeem ua kom zoo, thiab cov khoom siv tuaj yeem tsim los tuav lub substrate nyob rau hauv ib txoj kev uas txhawb nqa cov plating. Rau cov txheej txheem-puab substrates, cov txheej txheem tshwj xeeb plating lossis kev siv cov anodes auxiliary tej zaum yuav xav tau.

• Dull los yog Tsaus Txheej: Zinc txheej npub los yog tsaus nti tuaj yeem yog vim tsis muaj qhov ci ntsa iab hauv chav da dej, qib siab ntawm impurities, lossis tsis raug plating tsis raug (xws li qhov kub siab tam sim no lossis da dej kub). Lub brightener concentration yuav tsum tau kuaj xyuas thiab kho yog tias xav tau. Lub da dej yuav tsum tau ntxuav kom huv si kom tshem tawm cov impurities, 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.