Kawm Txog Kev Tiv Thaiv Corrosion Ntawm Titanium Alloy Roj Zoo Yeeb Nkab
Lub ntsiab lus ntawm titanium alloy corrosion kuj yog tias titanium yog ib qho thermodynamically tsis ruaj khov nrog tus qauv electrode peev xwm ntawm tsuas yog -1.63 V (tus qauv hydrogen electrode HSE). Yog li ntawd, titanium thiab titanium alloys yog yooj yim heev los tsim ib tug nruam, ntom thiab nyias nto oxide zaj duab xis nyob rau hauv cov huab cua los yog txawm dej, uas yog tsim los ntawm ib tug puab txheej ntawm Ti2O3 thiab ib txheej txheej ntawm TiO2, thiab nws tseem mus thicken li lub redox cov tshuaj tiv thaiv tshwm sim. Cov oxide zaj duab xis npog saum npoo ntawm titanium alloy cuam tshuam cov tshuaj tiv thaiv kev hloov pauv thiab txo lossis cuam tshuam cov kev sib cais ntawm titanium alloy hauv nruab nrab corrosive, ua rau passivation.
Txawm li cas los xij, titanium alloy muaj peev xwm zoo dua li lwm cov alloys. Thaum ua ke nrog cov sib txawv alloys, titanium alloy yog tiv thaiv raws li ib tug cathode, uas accelerates corrosion ntawm cov hlau txuas thiab tuaj yeem ua rau kev puas tsuaj. Yog li ntawd, cov kws tshawb fawb hauv tsev thiab txawv teb chaws kuj tau ua qee yam kev tshawb fawb txog kev tiv thaiv corrosion ntawm titanium alloy hauv cov kav dej thiab cov roj casing.
1. Titanium alloy laum yeeb nkab
Peng et al. soj ntsuam kev qaug zog ntawm titanium alloy laum kav. Cov txiaj ntsig tau pom tias nyob rau hauv huab cua, nrog rau qib steel nce, lub neej qaug zog ntawm lub laum yeeb nkab yuav txuas ntxiv, thaum nyob rau hauv drilling av nkos, kev qaug zog ntawm titanium alloy laum yeeb nkab yog qhov zoo tshaj plaws. Daim duab 3a qhia txog kev qaug zog ntawm cov tho yeeb nkab sib txawv hauv chav kub H2S av nkos. Lub xub ntiag ntawm H2S av nkos yuav txo tau lub neej qaug zog ntawm txhua qhov kev xyaum yeeb nkab, qhia tias cov yeeb nkab laum muaj qhov rhiab heev rau H2S av nkos. Nyob rau hauv H2S av nkos ib puag ncig, lub neej qaug zog ntawm titanium alloy laum yeeb nkab yog siab dua li ntawm cov yeeb nkab steel laum xws li G105, S135 thiab V150. Daim duab 3b qhia txog SN nkhaus ntawm cov kav dej sib txawv hauv H2S av nkos ntawm 100 degree. Piv nrog rau chav tsev kub huab cua, lub neej qaug zog ntawm G105, S135, V150 thiab Ti qauv yog txo qis. Qhov sib txuas ntawm H2S av nkos thiab qhov kub thiab txias muaj kev cuam tshuam ntau dua rau lub neej qaug zog ntawm cov yeeb nkab laum tshaj li ib qho. Raws li qhov kev sib txuas no, lub neej qaug zog ntawm titanium laum yeeb nkab tseem muaj qhov zoo dua li lwm cov yeeb nkab laum.
Fig.3 Fatigue curves ntawm G105, S135, V150 thiab Ti laum yeeb nkab qauv nyob rau hauv txawv kev ua hauj lwm
Chen et al. siv cov kev kho deg tshiab micro-arc oxidation thev naus laus zis los ntxiv qhov sib txawv ntawm sodium tungstate rau cov tshuaj oxidation los ua micro-arc oxidation ntawm qhov chaw ntawm TC4 titanium alloy laum yeeb nkab. Cov kev tshawb fawb tau pom tias tungsten doping tuaj yeem txhim kho qhov nyuaj thiab corrosion kuj ntawm TC4 titanium alloy laum yeeb nkab. Thiab thaum lub concentration ntawm sodium tungstate yog 3 g / L, qhov kev ua tau zoo ntawm micro-arc oxidation txheej ntawm titanium alloy laum yeeb nkab yog qhov zoo tshaj plaws.
Nyob rau hauv cov ntsiab lus, corrosion qaug zog lub neej ntawm titanium alloy laum yeeb nkab nyob rau hauv high kub thiab siab sulfur ib puag ncig yog zoo dua li ntawm steel laum yeeb nkab, thiab kev kho deg ntawm TC4 titanium alloy yuav zoo txhim kho hardness thiab corrosion kuj ntawm laum yeeb nkab. Txawm li cas los xij, tseem muaj qee qhov kev tshawb fawb txog kev txhim kho corrosion kuj ntawm titanium alloy laum yeeb nkab los ntawm kev kho saum npoo, uas tseem muab kev taw qhia rau kev tshawb fawb yav tom ntej.
2. Titanium alloy roj casing
Wang et al. tau kawm txog cov khoom siv titanium alloy TC4 uas tuaj yeem siv los ua cov roj casing. Lawv pom tias nyob rau hauv ib puag ncig acidic corrosion, muaj lub zos electrochemical corrosion nyob rau saum npoo ntawm TC4 alloy, feem ntau pitting corrosion. Hauv kev ua tiav cov kua dej uas muaj CO2, qhov kev txhim kho corrosion ntawm TC4 alloy yog qhov hnyav dua, tab sis qhov corrosion kuj zoo dua hauv cov dej tsim muaj CO2. Nyob rau saum toj no ob CO2-muaj cov xov xwm corrosive, TC4 alloy muaj kev tiv thaiv zoo heev rau kev ntxhov siab corrosion tawg. Piv nrog rau thaj av ib puag ncig, TC4 alloy yog rhiab heev rau kev ntxhov siab corrosion cracking nyob rau hauv lub hiav txwv tob.
Nyob rau tib lub sijhawm, Wang et al. kuj tau kawm txog kev txhim kho corrosion ntawm TC4 titanium alloy nyob rau hauv qhov sib txawv ntawm kev ntxhov siab loading thiab pom tias pits tshwm nyob rau saum npoo ntawm cov qauv loaded elastic kev nyuaj siab, tab sis lub degree ntawm pitting kuj yog lub teeb, thiab cov nto zaj duab xis txheej qhia n-hom semiconductor. Cov khoom thiab muaj cation selective permeability. Thaum cov pits saum npoo ntawm cov qauv raug cov yas kev nyuaj siab tau tob dua thiab dav dua, thiab cov semiconductor hom ntawm cov yeeb yaj kiab saum npoo tau hloov mus rau p-hom, anions xws li Cl- thiab CO32- tau yooj yim dua adsorbed thiab rhuav tshem. cov yeeb yaj kiab tiv thaiv, thiab tiv tauj nrog lub substrate los ntawm cov yeeb yaj kiab tiv thaiv, ua rau txo qis hauv corrosion kuj ntawm TC4 titanium alloy.
Tam sim no, cov kev ua haujlwm ntawm cov roj thiab cov roj tsis zoo yog qhov hnyav. Qhov kub thiab txias yuav txo tau lub zog tawm los thiab elastic modulus ntawm tubing thiab casing, thiab kev kub siab yuav ua rau kom lub siab ntawm tubing thiab casing. Raws li qhov kev txiav txim ntawm H2S, CO2 thiab Cl- ib leeg lossis ua ke, qhov corrosion ntawm tubing thiab casing tau dhau los ua hnyav dua. Titanium alloy tubing thiab casing tuaj yeem daws tau qhov teeb meem ntawm downhole corrosion tsis ua hauj lwm, tab sis tam sim no kev tshawb fawb ntawm corrosion kuj ntawm titanium alloy tubing thiab casing tseem tsis tiav thiab xav tau kev tshawb fawb ntxiv.
3. Titanium alloy roj zoo kav
Schutz et al. piv cov kev tiv thaiv corrosion ntawm UNS R55400 alloy yeeb nkab hlua nrog rau lwm yam oilfield titanium alloy yeeb nkab hlua. Cov ntaub ntawv kuaj xyuas corrosion ntawm UNS R55400 pipeline txoj kev loj hlob tau pom tias titanium alloy tau txhim kho kev tiv thaiv rau SSC thiab hauv zos pitting thiab crevice corrosion nyob rau hauv acidic thiab non-acidic chloride-nplua nuj dej ib puag ncig cuam tshuam nrog kev lag luam roj.
Table 2 qhia txog qhov kwv yees ib puag ncig kev pab cuam txwv ntawm ntau hom titanium alloys nyob rau hauv qhov chaw sib txawv oilfield. Nws tuaj yeem pom tau tias UNS R55400 thiab UNS R56404 titanium alloys muaj qhov ua tau zoo tshaj plaws nyob rau hauv acidic thiab non-acidic chloride-nplua nuj dej puag ncig, thiab lub zog siab tshaj plaws yog UNS R58640 beta titanium alloy.
Wei et al. Kawm txog cov nyhuv ntawm qhov kub thiab txias ntawm kev hloov pauv ntawm microstructure thiab tus cwj pwm corrosion ntawm Ti-Mo titanium alloy hauv hydrochloric acid. Lawv pom tias thaum lub annealing kub tshaj 850 degree, lub MoO3 thiab TiO2 passivation films tsim nyob rau saum npoo ntawm cov titanium alloy ceev dissolution, tus nqi corrosion nce, thiab -phase thiab -phase microgalvanic hlwb raug tsim. Tsis tas li ntawd, cov zaj duab xis passivation qhia tau hais tias n-hom semiconductor yam tsis muaj kev ywj pheej ntawm annealing kub.
Los ntawm cov kev tshawb fawb saum toj no, nws tau pom tias qhov kub thiab txias, cov kua qaub siab, thiab cov dej uas tsis yog-acidic chloride-nplua nuj nyob ib puag ncig yuav cuam tshuam rau corrosion kuj ntawm titanium alloys. Qhov kev txiav txim siab no muaj kev taw qhia tseem ceeb rau kev ua kom zoo ntawm titanium alloy cov ntaub ntawv yav tom ntej.
