Dab tsi yog qhov cuam tshuam ntawm hydrogen evolution los ntawm hluav taws xob cua sov raj ntawm electroplating?

Dab tsi yog qhov cuam tshuam ntawm hydrogen evolution los ntawm hluav taws xob cua sov raj ntawm electroplating?

Teb: Hydrogen evolution yuav luag inevitable thaum lub sij hawm electroplating txheej txheem. Lub precipitated hydrogen nkag mus rau hauv cov txheej thiab substrate hlau, ua rau hydrogen embrittlement thiab cuam tshuam rau cov khoom siv ntawm cov khoom. Yog hais tias precipitated hydrogen nyob rau ntawm qhov chaw nyob rau hauv daim ntawv ntawm cov npuas, nws yuav ua rau pores thiab pits nyob rau hauv lub txheej. Txoj kev tshem tawm yog ntxiv oxidants, wetting agents, thiab tom qab plating hydrogen tshem tawm kev kho mob. Lub xub ntiag ntawm cov organic impurities muaj cov nyhuv adsorption ntawm hydrogen, ua rau nws nyuaj rau hydrogen npuas kom dim ntawm lub cathode nto, ua rau nws yooj yim rau pinholes thiab pitting.

Txhim kho qhov sib tov ntawm cov tshuaj plating yuav muaj qee yam cuam tshuam rau kev txo qis cov pa roj hydrogen ntawm cov plating.

67. Nyob rau hauv cov txheej txheem tshem tawm cov roj, hom roj zoo li cas rau cov kuab tshuaj organic (xws li trichloroethylene) tshem tawm?

Teb: Nws yog tsim nyog tshem tawm cov roj ntxhia uas tsis yog saponified los ntawm qhov chaw. Cov rog muaj peev xwm muab faib ua tsiaj, zaub, thiab roj ntxhia raws li lawv qhov chaw. Tsiaj thiab zaub roj tau txais saponification nyob rau hauv alkaline tej yam kev mob, yog li lawv kuj hu ua "saponified roj"; Cov roj ntxhia uas tsis muaj cov nyhuv no tseem hu ua "tsis yog saponified roj".

Saponified roj thiab cov rog tuaj yeem raug tshem tawm tau zoo nrog alkali, thaum cov roj uas tsis yog saponified thiab cov rog tsis tuaj yeem raug tshem tawm nrog alkali vim lawv tsis muaj tshuaj lom neeg nrog alkali. Organic kuab tshuaj muaj peev xwm ua tau zoo yaj cov roj uas tsis yog saponified thiab cov rog, yog li lawv yog qhov tsim nyog rau tshem tawm cov roj ntxhia uas tsis yog saponified thiab cov rog.

68. Piav txog lub hauv paus ntsiab lus ntawm kev tshem tawm cov roj electrolytic?

Teb: Thaum tshem cov roj los ntawm electrolysis, txawm tias cov khoom siv los ua cathodes lossis anodes, cov pa roj ntau tawm ntawm lawv qhov chaw. Cov txheej txheem no yog qhov tseem ceeb ntawm electrolysis ntawm dej:

2H2O=2H2↑ plus O2↑

Thaum lub workpiece ua hauj lwm pab raws li ib tug anode, lub nto mus rau ib tug oxidation txheej txheem thiab tso pa oxygen:

4OH--4e=O2↑ plus 2H2O

Thaum lub workpiece ua hauj lwm raws li lub cathode, lub nto undergoes ib tug txo cov txheej txheem thiab tso tawm hydrogen gas:

4H2O + 4e=2H2↑ plus 4OH-

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