Aluminium (Al), uas zoo nkaus li silvery dawb, belongs rau lub ntsej muag-centered cubic qauv nrog ib tug lattice tas li ntawm 404959.6 nanometers, ib tug txheeb ze atomic mass ntawm 26.8, ib tug melting point ntawm 658 degree, thiab ib tug boiling point ntawm 2000 degree. Aluminium tsis tshwm sim nyob rau hauv kev lag luam zinc. Txawm li cas los xij, txhuas yog txhob txwm muab ntxiv rau molten zinc thaum kub-dip galvanizing. Lub hom phiaj yog txhawm rau txhim kho qhov ci ntawm zinc txheej ntawm cov kav hlau, txhim kho nws qhov yooj yim, hloov cov qauv ntawm cov hlau-zinc alloy txheej, thiab tiv thaiv kev cuam tshuam ntawm cov hlau hauv cov zinc molten. Ib qho kev qhia ntxaws ntxaws yog raws li hauv qab no:
(1) Aluminium txhim khu lub gloss thiab yooj ntawm galvanized steel kav.
Raws li txoj cai, kom ua tiav qhov no, tsuas yog {{0}} 02% txhuas hauv cov zinc molten txaus. Txawm li cas los xij, vim tias txhuas tau yooj yim oxidized ntawm qhov chaw ntawm cov zinc molten, raws li kev paub dhau los, kwv yees li 0.2% txhuas yuav tsum tau ntxiv kom muaj 0.02% txhuas cov ntsiab lus hauv cov zinc molten. Vim muaj kev sib raug zoo siab ntawm aluminium thiab oxygen, uas tsim cov alumina txheej, txheej txheej no zoo tiv thaiv cov pa oxygen, tiv thaiv lub hauv paus molten zinc thiab molten zinc los ntawm oxidation. Ib yam li ntawd, lwm cov khoom siv hlau hauv cov zinc molten kuj tseem tiv thaiv los ntawm oxidation. Raws li peb paub, zinc oxide tsim tom qab oxidation ntawm molten zinc yog daj, thiab oxides ntawm txhuas thiab cadmium kuj daj. Yog tsis muaj kev cuam tshuam ntawm txhuas, galvanized txheej saum npoo yuav ua rau tarnished nrog cov khoom daj, zoo heev cuam tshuam nws gloss. Yog li ntawd, ib co nyiaj ntawm txhuas yog ntxiv thaum kub-dip galvanizing kom tau ib tug kaj galvanized txheej. Lub caij no, thaum cov zinc molten muaj 0.2% txhuas, cov qauv zoo tshaj plaws tuaj yeem tau txais, thiab qhov yooj ntawm cov txheej galvanized yog qhov zoo.
Txawm li cas los xij, American Society for Testing and Materials pom zoo kom tsis txhob siv cov khoom siv txhuas ua cov xim hlau ua kom ci, thiab yog tias siv, nws yuav tsum txwv qis dua 0.01%.
(2) Hloov kho cov qauv ntawm cov txheej txheem galvanized
Txoj kev xav, kom ua tiav lub hom phiaj ntawm kev hloov kho cov txheej txheem galvanized, cov ntsiab lus txhuas ntawm {{0}}.2 rau 0.3% hauv cov zinc molten yog txaus. Txawm li cas los xij, hauv kev tsim khoom tiag tiag, txhuas hauv cov zinc molten yooj yim reacts nrog oxygen thiab noj. Yog li ntawd, kom tswj tau cov ntsiab lus txhuas ntawm 0.2 mus rau 0.3% hauv cov zinc molten, kwv yees li 1.5% mus rau 3.5% txhuas yuav tsum tau ntxiv. Txhawm rau nthuav qhia cov txiaj ntsig ntawm cov ntsiab lus ntawm txhuas ntawm kev hloov kho cov txheej txheem galvanized, cia peb saib cov kev hloov pauv hauv cov txheej txheem galvanized raws li cov ntsiab lus txhuas maj mam nce los ntawm qis mus rau siab:
Kev nce hauv cov ntsiab lus ntawm txhuas rau 0.05% hauv cov zinc molten yog npaj los txhim kho qhov gloss ntawm txheej galvanized tab sis tsis cuam tshuam rau nws cov qauv. Yog li ntawd, cov txheej txheem galvanized yog tib yam li cov plated los ntawm cov zinc molten ntshiab, muaj cov txheej txheem adhesion (theem a), cov txheej txheem nruab nrab (theem), txheej txheej me ntsis tawg (theem δ₁), txheej drifting (theem S), thiab ib txheej zinc ntshiab (theem η). Qhov sib txawv ntawm galvanized txheej plated los ntawm ntshiab molten zinc yog nyob rau hauv crystalline duab ntawm cov theem.
Thaum cov ntsiab lus txhuas nyob rau hauv cov zinc molten yog 0.1%, cov muaju ntawm cov txheej txheem drifting (theem δ₁) muaj nyob rau hauv cov blocks loj thiab tsis muaj txheej txheem txuas ntxiv lawm tab sis raws li kev sib cais.
Thaum cov ntsiab lus txhuas nyob rau hauv cov zinc molten yog 0.15%, qhov kev faib tawm ntawm cov txheej txheem drifting (theem δ₁) kuj tsis tas mus li tab sis muaj cov loj dua, sib koom ua ke sib cais crystalline pawg, tsuas yog cov txheej (theem δ₁) qhia ib tug me ntsis denser qauv.
Thaum cov ntsiab lus txhuas hauv cov zinc molten yog 0.24%, cov nyhuv inhibiting ntawm etching (alloying) muaj zog. Yog hais tias lub immersion galvanizing yog khaws cia ntawm qhov kub ntawm 440 degree rau 1 teev nyob rau hauv no molten zinc thiab tom qab ntawd soj ntsuam, tsis muaj cov tshuaj tiv thaiv tau tshwm sim. Yog li ntawd, tsuas yog ib txheej zinc ntshiab muaj nyob rau ntawm galvanized txheej ntawm cov qauv. Qhov no yog vim hais tias cov tshuaj tiv thaiv ntawm txhuas thiab cov yeeb nkab steel ua ib zaj duab xis nyias ntawm FeAl₃ (los yog Fe₂Al₅ raws li qee qhov chaw) cov khoom sib txuas, cuam tshuam cov diffusion ntawm hlau ions ntawm zinc.
Los ntawm cov saum toj no, nws tuaj yeem pom tias qhov nyiaj ntawm txhuas yog qhov tseem ceeb hauv kev hloov cov qauv ntawm cov txheej galvanized. Thaum cov ntsiab lus ntawm txhuas yog tsau, cov txheej txheem tsis xws li lub sij hawm immersion, fluidity (raws li qhia hauv daim duab 3-5), thiab immersion kub kuj cuam tshuam qhov kev hloov ntawm zinc txheej txheej txheem. Yog li ntawd, nyob rau hauv kub-dip galvanizing ntau lawm, kev sib raug zoo ntawm peb yam tseem ceeb yog stipulated los ntawm cov txheej txheem specifications, thiab tsuas yog nyob rau hauv nruj tswj kev khiav hauj lwm tej yam kev mob muaj peev xwm xav tau galvanized txheej.
(3) Tiv thaiv kev cuam tshuam ntawm cov hlau hauv cov zinc molten
Aluminium reacts nrog hlau nyob rau hauv molten zinc los ua peb lub tebchaw: FeAl, FeAl₂, thiab FeAl₃, yog li txo nws cov kev cuam tshuam rau cov galvanized txheej.
