Vim li cas Corrosion Resistance Matters hauv Aluminium Qws
Aluminium pas nrig yog siv nyob rau hauv cov qauv kev txhawb nqa, machined fittings, hluav taws xob connectors thiab fasteners, thiab nyob rau hauv ntau yam ntawm cov kev siv cov pas nrig yuav tsum muaj sia nyob xyoo ntawm raug ya raws, tshuaj los yog ntsev cua. Aluminium yog intrinsically corrosion resistant vim hais tias ib tug nyias, ntom oxide zaj duab xis ntaub ntawv instantly ntawm ib tug tshiab nto thiab blocks ntxiv tua. Qhov kev tiv thaiv ntuj tuaj yeem ua rau tsis muaj zog lossis ntxiv dag zog los ntawm cov khoom siv hlau alloy thiab los ntawm kev npaj qhov saum npoo li cas, uas yog vim li cas ob lub pas nrig ntawm qhov loj me tuaj yeem coj txawv txawv hauv tib qhov chaw.
Yam Uas Txiav Txim Corrosion Resistance
Alloy muaj pes tsawg leeg yog thawj yam. Cov qib ntshiab aluminium xws li 1xxx series muab qhov zoo tshaj plaws kev tiv thaiv corrosion, thaum tooj liab - muaj cov alloys hauv 2xxx thiab 7xxx series yog ntau dua rau pitting thiab galvanic nres. Magnesium-cov kabmob 5xxx alloys xws li 5052 thiab 5083 yog tshwj xeeb muaj nuj nqis rau cov dej ntsev. Kev kho saum npoo yog qhov thib ob: anodizing electrochemically thickens oxide txheej thiab tuaj yeem ua kom ntev kev pab cuam lub neej. Qhov thib peb yam yog ib puag ncig nws tus kheej. Chlorides nyob rau hauv marine huab cua, acidic los yog alkaline txheej txheem kua, thiab kev sib cuag nrog ntau noble hlau tag nrho ua rau corrosion, thiab tus pas nrig yuav tsum tau teev nyob rau hauv lub siab.
Yuav ua li cas Anodizing tiv thaiv Aluminium Qws
Anodizing yog txheej txheem electrochemical uas loj hlob ib txheej tswj oxide ntawm tus pas nrig. Hauv hom II sulfuric acid txheej txheem, tus pas nrig yog muab tso rau hauv 15-20% sulfuric acid da dej ntawm ib ncig ntawm 20 C thiab kho hauv qab 12-18 V DC los tsim ib txheej ntawm 10-25 microns. Cov txheej anodic yog ib qho nyuaj, feem ntau yog 500-800 HV, thiab muab khi rau hauv dej kub los yog npib tsib xee acetate kaw lub qhov hws txhawm rau txhawm rau tiv thaiv corrosion. Anodized 6061 pas nrig feem ntau tiv taus ntau dua 1,000 xuab moos hauv kev ntsuas ntsev ntsev ib ASTM B117, qib kev ua tau zoo uas cov pas nrig tsis sib xws.
Common Corrosion Hom thiab Kev Tiv Thaiv
Galvanic corrosion tshwm sim thaum txhuas ua ke nrog cov hlau zoo dua qub xws li hlau lossis tooj dag nyob rau hauv lub xub ntiag ntawm electrolyte. Nws yog tiv thaiv los ntawm kev cais cov hlau nrog insulating gaskets, coatings los yog xaiv fastener kom raug. Pitting yog tshwm sim los ntawm chlorides thiab tshwm raws li cov kab noj hniav me me; nws yog mitigated los ntawm xaiv magnesium los yog manganese- bearing alloys thiab los ntawm anodizing los yog pleev xim rau saum npoo. Crevice corrosion tsim nyob rau hauv shielded thaj chaw uas stagnant noo noo sau, yog li nws yog qhov zoo tshaj plaws zam los ntawm cov kua dej- tus phooj ywg tsim thiab tu tsis tu ncua. Kev ntxhov siab corrosion cracking yog ib qho kev pheej hmoo nyob rau hauv qee qhov siab -lub zog tempers, uas yog vim li cas overaged tempers xws li T73 yog teev rau 7xxx tseem ceeb daim ntawv thov.
Kev kuaj Corrosion Resistance
Kev ntsuam xyuas tus qauv tso cai rau cov neeg yuav khoom sib piv cov pas nrig ntawm qhov zoo li-rau{{1} zoo li hauv paus. ASTM B117 yog qhov kev ntsuam xyuas cov tshuaj ntsev tsis zoo, thaum ASTM G85 npog cov txheej txheem tshuaj tsuag ntsev hloov rau cov khoom coated. Rau kev pabcuam hauv hiav txwv, ASTM G44 siv alternating immersion hauv 3.5% sodium chloride tov los simulate tidal aav. Alloys xws li 5086 nrog ib ncig ntawm 4% magnesium qhia qhov corrosion qis dua 0.1 hli hauv ib xyoos hauv dej hiav txwv, thiab qhia qhov kev ntsuam xyuas tsim nyog hauv kev txiav txim yuav muab ob tus neeg yuav khoom thiab tus neeg muag khoom pom meej qhov kev lees paub.
Xaiv Txoj Cai Qws rau Ib puag ncig
Rau cov ntug dej hiav txwv thiab sab ntug dej hiav txwv, xaiv ib qho 5xxx alloy xws li 5052 lossis 5083 thiab qhia kom meej anodized lossis pleev xim tiav yog tias qhov saum npoo yuav ncaj nraim nrog dej ntsev. Rau kev ua tshuaj, 1xxx thiab 3xxx alloys tiv taus ntau cov kua qaub me me thiab alkalis thiab yooj yim los ntxuav. Rau siab - daim ntawv thov muaj zog qhov twg corrosion yog qhov kev txhawj xeeb thib ob, 6061-T6 nrog anodizing muaj qhov ua tau zoo, thaum 7075 yuav tsum tau siv tsuas yog nyob rau hauv qhov kub thiab txias thiab tiv thaiv txheej hauv qhov chaw ntub dej. Kev lees paub cov alloy, npau taws, ua tiav thiab ntsuas tus qauv ntawm kev txiav txim theem tiv thaiv kev ua haujlwm tsis zoo tom qab.
Cov lus nug nquag
Q: Puas yog ntshiab txhuas pas nrig corrode hauv dej ntsev?
Yog lawm, dhau sij hawm: 1050 thiab 1060 pitting tshwm sim nyob rau hauv ib puag ncig chloride vim tias cov oxide tiv thaiv hauv zos raug tawm tsam. Rau kev pabcuam marine, 5083, 5052 lossis anodized 6061 tau teev tseg.
Q: Ntev npaum li cas anodized aluminium pas nrig sab nraum zoov?
Nrog rau 20 mus rau 25 micron kaw anodic zaj duab xis, 15 mus rau 30 xyoo nyob ntawm ib puag ncig. Cov chaw lag luam thiab cov ntug dej hiav txwv xav tau cov zaj duab xis tuab dua thiab ntxuav tsis tu ncua.
Q: Puas tuaj yeem aluminium pas nrig corrode thaum sib cuag nrog hlau?
Yog, galvanic corrosion: nyob rau hauv ib qho electrolyte, cov hlau thiab txhuas ob peb corrodes cov txhuas nyob ze ntawm qhov sib koom ua ke. Cais cov hlau nrog cov ntxhua khaub ncaws, pleev xim, lossis anodizing tiv thaiv kev sib cuag.
Q: Qhov twg aluminium alloy muaj qhov zoo tshaj plaws corrosion kuj?
5083, 5052 thiab 6061 nyob rau hauv 5xxx thiab 6xxx tsev neeg, nrog rau cov ntshiab 1060, muab qhov zoo tshaj plaws dav dav thiab marine resistance. 5083 yog qhov ntsuas rau seawater service.
Q: Puas yog pitting corrosion tiv thaiv ntawm txhuas pas nrig?
Tsis yog hauv cov tshuaj chloride nkaus xwb, tab sis nws yog tswj tau: xaiv 5xxx alloy, ua kom lub ntsej muag anodized los yog pleev xim rau, tsis txhob galvanic khub niam txiv, thiab yaug qhov chaw marine nrog dej tshiab.
Q: Yuav ua li cas pH cuam tshuam rau corrosion kuj ntawm txhuas pas nrig?
Aluminium cia siab rau cov yeeb yaj kiab oxide uas ruaj khov nyob nruab nrab ntawm pH 4 thiab pH 9. Sab nraum lub qhov rais zaj duab xis tawg thiab cov amphoteric hlau corrodes sai, yog li muaj zog acids thiab muaj zog alkalis tua txhuas pas nrig txawm tias nws ua tau zoo hauv nruab nrab cov dej tshiab thiab cov cua.