Kev kho saum npoo ntawm cov raj mis yas khoom siv ntau nrog txheej kev kho mob thiab txheej kho. Feem ntau, cov crystallinity ntawm cov yas muaj qhov loj, qhov polarity yog me lossis tsis ncov qaum, thiab lub zog saum npoo muaj tsawg, uas yuav cuam tshuam rau kev nplaum ntawm txheej. Raws li yas yog ib hom ntawm cov tsis muaj qhov thaiv tsis tau, nws tsis tuaj yeem ncaj ncaj rau ntawm cov yas raws li cov txheej txheem txheej txheem electroplating. Yog li no, ua ntej kev kho saum npoo, tsim nyog ua ntej yuav tsum tau nqa tawm txhawm rau txhim kho qhov nplaum ntawm cov xim txheej thiab muab cov kev coj ua hauv qab nrog cov nplaum zoo rau cov txheej.
1. pretreatment ntawm txheej
Qhov kev txiav txim siab ua ntej suav nrog kev kho deg ntawm cov yas nto, uas yog, cov roj thiab pwm tso tawm tus neeg saib xyuas kev ntxuav tu nto, thiab kev ua kom zoo kho cov yas kho, kom thiaj li txhim kho qhov nplaum ntawm cov xim.
(1) tsis zoo ntawm cov khoom siv yas fwj. Zoo ib yam li saum npoo degreasing ntawm cov khoom lag luam hlau, lub raj mis yas khoom tuaj yeem ntxuav nrog cov kuab tshuaj organic los yog degreased nrog cov dej ua kua alkaline uas muaj surfactant. Cov kuab tshuaj organic degreasing yog qhov tsim nyog rau kev ntxuav paraffin, beeswax, roj thiab lwm cov av plua plav tawm ntawm cov yas. Cov kuab tshuaj organic siv yuav tsum tsis yaj, yauv los yog tawg rau yas, nrog lub rwj qis, tsis ruaj, tsis muaj tshuaj lom thiab tsis txhuam.
Cov dej ua kua alkaline yog tsim nyog rau degreasing ntawm alkali resistant plastics. Kev daws muaj caustic sis dej qab zib, kua ntsev ua kua ntsev thiab ntau yam tshuaj muaj zog. Qhov feem ntau siv surfactant yog op series, piv txwv li alkylphenol polyoxyethylene ether, uas yuav tsis ua npuas ncauj lossis nyob twj ywm rau ntawm cov yas.
(2) kev ua kom zoo ntawm cov nplaim yas ntim khoom muag. Qhov kev ua kom zoo li no yog txhawm rau txhim kho lub zog saum npoo ntawm plastics, uas yog kom hais, tsim ib co ncov qaumteb qabteb pawg rau ntawm cov pob zeb los yog ua kom lawv coarsen, thiaj li ua rau cov xim ua kom yooj yim ntub thiab adsorbed nyob rau saum npoo ntawm cov khoom. Muaj ntau txoj hauv kev ntawm kev ua kom nto, xws li tshuaj lom neeg oxidation, nplaim oxidation, hnyav vapor etching thiab corona paug oxidation. Ntawm lawv, txoj kev siv ntau tshaj plaws yog tshuaj siv lead ua oxidation, uas feem ntau siv los ua cov tshuaj chromic acid kho. Nws cov mis ib txwm yog potassium dichromate 4.5%, dej 8.0%, concentrated sulfuric acid (tshaj li 96%) 87.5%. Qee cov khoom siv yas hwj, xws li polystyrene thiab ABS yas, kuj tseem tuaj yeem pleev xim ncaj qha.
2. pretreatment ntawm txheej
Lub hom phiaj ntawm txheej txheej txheej ua kom tsis txhob muaj txheej txheem txhawm rau txhim kho qhov nplaum ntawm cov xim thiab cov yas yas thiab ua kom muaj txheej txheem ntawm cov xim hlau zoo nkauj rau cov yas. Cov txheej txheem txheej txheem feem ntau suav nrog kev kho coarsening, kev siv roj tawm, tshuaj coarsening, tshuaj kho kom haum, ua kom rov ua kom zoo dua, txo kev kho thiab tshuaj plating. Thawj peb yog txhawm rau txhim kho lub adhesion ntawm txheej, thiab plaub kawg yog los tsim cov hlau nplaum uas muaj txheej txheem.
(1) tshuab coarsening thiab coarsening tshuaj lom neeg. Mechanical coarsening thiab coarsening tshuaj yog siv los coarsen yas nto los ntawm kev siv tshuab thiab tshuaj feem, yog li ua kom qhov chaw sib tiv tauj ntawm cov txheej thiab lub substrate. Feem ntau hais lus, txoj hlua khi ntawm kev sib tsoo ntawm cov neeg kho tshuab tsuas yog kwv yees li 10% ntawm kev sib koom tes tshuaj.
(2) tshuaj roj tshem tawm. Cov txheej txheem ntawm degreasing ua ntej txheej ntawm yas saum npoo yog tib yam li uas ua ntej txheej.
