Galvanizing
Yam ntxwv:
Zinc kuj ruaj khov nyob rau hauv cov huab cua qhuav thiab tsis yooj yim discolored. Hauv cov dej thiab qhov chaw ntub dej, nws hnov mob nrog oxygen lossis carbon dioxide los ua oxide lossis alkaline zinc carbonate zaj duab xis, uas tuaj yeem tiv thaiv zinc los ntawm kev txuas ntxiv mus rau oxidize thiab muab kev tiv thaiv.
Zinc feem ntau raug rau corrosion hauv acids, alkalis, thiab sulfides. Cov txheej txheej galvanized feem ntau yuav tsum tau txais kev kho mob passivation. Tom qab passivation nyob rau hauv chromic acid los yog chromate tov, cov tsim passivation zaj duab xis yog tsis yooj yim mus rau humid huab cua, zoo heev txhim khu nws anti-corrosion muaj peev xwm. Rau qhov chaw caij nplooj ntoos hlav, nyias-walled qhov chaw (phab ntsa thickness <0.5m), thiab steel qhov chaw uas yuav tsum tau muaj zog txhua yam, yuav tsum tau muab tshem tawm hydrogen, thaum tooj liab thiab tooj liab alloy qhov chaw yuav tsis xav tau hydrogen tshem tawm.
Galvanizing muaj tus nqi qis, ua haujlwm yooj yim, thiab muaj txiaj ntsig zoo. Lub peev xwm txheej txheem ntawm zinc yog qhov tsis zoo, yog li zinc txheej yog anodic txheej rau ntau cov hlau.
Galvanization yog dav siv nyob rau hauv atmospheric tej yam kev mob thiab lwm yam dej siab ib puag ncig. Tab sis nws tsis haum rau siv los ua ib qho kev sib txhuam.
Cchrome plating
Yam ntxwv: Rau qhov chaw uas tuaj rau hauv kev sib cuag nrog dej hiav txwv cua lossis dej hiav txwv, thiab hauv dej kub siab tshaj 70℃, cadmium plating yog qhov ruaj khov, muaj zog corrosion kuj, zoo lubrication, thiab dissolves maj mam nyob rau hauv dilute hydrochloric acid, tab sis yog heev soluble nyob rau hauv nitric acid thiab insoluble nyob rau hauv alkali. Nws cov oxide kuj yog insoluble hauv dej. Cadmium txheej yog softer dua zinc txheej, nrog tsawg hydrogen embrittlement thiab muaj zog adhesion.
Ntxiv mus, nyob rau hauv tej yam kev mob ntawm electrolytic, lub cadmium txheej tau yog ntau aesthetically pleasing tshaj zinc txheej. Tab sis cov roj uas tsim los ntawm cadmium thaum lub sij hawm melting yog tshuaj lom, thiab soluble cadmium ntsev kuj yog tshuaj lom. Raws li ib txwm muaj, cadmium ua raws li cov txheej txheem cathodic ntawm cov hlau thiab ua cov txheej txheem anodic nyob rau hauv dej hiav txwv thiab cov huab cua kub.
Nws yog tsuas yog siv los tiv thaiv qhov chaw los ntawm atmospheric corrosion los ntawm seawater los yog cov ntsev zoo sib xws, nrog rau saturated seawater vapor. Ntau qhov chaw hauv aviation, maritime, thiab hluav taws xob industries, springs, thiab threaded qhov chaw yog plated nrog cadmium. Nws tuaj yeem polished, phosphated, thiab siv los ua cov xim pleev xim, tab sis tsis tuaj yeem siv los ua cov tais diav.
Chromium plating
yam ntxwv:
Chromium yog qhov ruaj khov heev hauv cov huab cua ntub, alkaline, nitric acid, sulfide, carbonate daws, thiab cov organic acids, thiab yooj yim soluble hauv hydrochloric acid thiab kub concentrated sulfuric acid. Nyob rau hauv qhov kev txiav txim ntawm ncaj qha tam sim no, yog hais tias lub chromium txheej ua hauj lwm raws li lub anode, nws yog yooj yim soluble nyob rau hauv caustic soda tov.
Cov txheej chromium muaj zog adhesion, siab hardness, 800-1000V, zoo hnav tsis kam, muaj zog lub teeb pom kev zoo, thiab kub kub kuj. Nws tsis hloov xim hauv qab 480℃, pib oxidize saum 500℃, thiab txo qis hardness ntawm 700℃. Nws qhov tsis zoo yog tias chromium yog ib qho nyuaj, nkig, thiab nws yooj yim rau detachment, tshwj xeeb tshaj yog thaum muaj kev hloov pauv cuam tshuam. Thiab nws muaj porosity.
Chromium hlau yog nquag mus rau passivation nyob rau hauv huab cua, uas ua rau tsim ib tug passivation zaj duab xis thiab yog li hloov lub peev xwm ntawm chromium. Yog li ntawd, chromium dhau los ua cathodic txheej ntawm hlau.
Nws tsis yog qhov zoo tshaj plaws los siv ncaj qha chrome plating raws li cov txheej txheem tiv thaiv corrosion ntawm qhov chaw ntawm cov hlau. Feem ntau, ntau txheej electroplating (piv txwv li tooj liab plating→npib tsib xee plating→chromium plating) yuav tsum ua kom tiav lub hom phiaj ntawm xeb
tiv thaiv thiab kho kom zoo nkauj. Tam sim no dav siv hauv kev txhim kho qhov hnav tsis kam ntawm qhov chaw, kho qhov ntev, lub teeb pom kev zoo, thiab cov teeb pom kev zoo nkauj.
Nickel plating
yam ntxwv:
Nickel muaj tshuaj lom neeg ruaj khov zoo hauv cov huab cua thiab cov tshuaj alkaline, tsis yooj yim discolored, thiab tsuas yog oxidized ntawm qhov kub siab tshaj 600.° C. Nws dissolves maj mam nyob rau hauv sulfuric acid thiab hydrochloric acid, tab sis yog yooj yim soluble nyob rau hauv dilute nitric acid. Nws yog yooj yim passivated nyob rau hauv concentrated nitric acid thiab yog li ntawd muaj zoo corrosion kuj.
Nickel plating muaj siab hardness, yooj yim rau polish, muaj lub teeb pom kev zoo, thiab tuaj yeem ua kom zoo nkauj. Nws qhov tsis zoo yog tias nws muaj porosity. Txhawm rau kov yeej qhov tsis zoo no, siv cov txheej txheem ntau txheej hlau, nrog npib tsib xee ua cov txheej txheem nruab nrab.
Nickel yog txheej txheej cathodic rau hlau thiab anodic txheej rau tooj liab.
Nws yog feem ntau siv los tiv thaiv cov hniav coatings txhawm rau tiv thaiv corrosion thiab ua kom zoo nkauj dua. Nickel plating ntawm cov khoom siv tooj liab yog qhov zoo tshaj plaws rau kev tiv thaiv corrosion, tab sis vim yog tus nqi siab ntawm npib tsib xee, tooj liab tin alloys feem ntau siv los ntawm nickel plating.
Post lub sij hawm: Nov-14-2024
