Kev tshuaj ntsuam titanium
Raws li cov khoom siv ua haujlwm tseem ceeb, cov hlau siv tau dav hauv kev lag luam, kev lag luam kho mob xws li lwm yam kev kho mob xws li tsis muaj zog, muaj zog ua haujlwm thiab zoo corrosion tsis kam. Kev txhim kho txheej txheem ntawm kev kho mob titanium thiab titanium alloys tuaj yeem faib ua peb lub sijhawm:
Thawj lub sij hawm yog sawv cev los ntawm ntshiab titanium thiab Ti-6AI-4V; lub sij hawm thib ob yog -type alloys, sawv cev los ntawm Ti-5A1-2.5Fe thiab Ti-6Al-7Nb; lub sij hawm thib peb yog cov khoom lom neeg zoo dua thiab elasticity txoj kev loj hlob ntawm. Beta titanium alloys nrog qis modulus yog cov kab tseem ceeb ntawm kev tiv thaiv. Daim ntawv thov ntawm cov ntaub ntawv tshiab titanium alloy yuav yog txoj kev loj hlob ntawm cov khoom siv kho mob tam sim no.
Kev tshawb fawb txog kev kho mob titanium alloy cov ntaub ntawv hauv kuv lub tebchaws tau pib xyoo 1970s. Northwest Nonferrous Metal Research Institute tsim Ti-2.5Al-2.5Mo-2.5Zr (TAMZ). Hauv xyoo 1990, Ti-2.5Al-2.5Mo-2.5Zr (TAMZ) nrog kev ywj pheej cov tswv cuab kev txawj ntse tau tsim. -6Al-4V, Ti-Al{17}}.5Fe thiab Ti{19}}Al-7Nb cov ntaub ntawv. Suav Academy ntawm Sciences kuj tau tsim ib qho tshiab beta titanium alloy Ti-24Nb-4Zr-7.6Sn. Tam sim no, txoj kev loj hlob ntawm titanium alloys hauv kuv lub teb chaws yog lub hom phiaj tseem ceeb ntawm kev tawg ntawm cov ntaub ntawv tshiab thiab kev siv cov khoom siv titanium alloy.
Corrosion ntawm titanium
Titanium yog ib qho thermodynamically tsis ruaj khov hlau nrog ib tug kuj tsis zoo passivation muaj peev xwm, nrog tus qauv electrode peev xwm ntawm -1.63V. Yog li ntawd, nws yog ib qho yooj yim los tsim ib tug oxide zaj duab xis nrog passivation zog nyob rau hauv cov huab cua thiab aqueous tov, thiab muaj zoo corrosion kuj.
Corrosion tsis kam ntawm titanium hauv cov xov xwm sib txawv
Nws yog ib qho tseem ceeb heev los kawm txog kev tiv thaiv corrosion ntawm cov ntaub ntawv kho mob. Ntawm qhov tod tes, qee cov hlau ions lossis cov khoom siv corrosion ntawm cov khoom cog nkag mus rau hauv cov ntaub so ntswg lom, uas tuaj yeem ua rau muaj kev cuam tshuam ntawm lub cev sib txawv; ntawm qhov tod tes, vim muaj cov kua dej hauv lub cev, kev ua haujlwm ntawm qee cov ntaub ntawv yuav raug degraded heev, ua rau muaj kev puas tsuaj sai lossis txawm tias tsis ua haujlwm. Tib neeg lub cev ib puag ncig yog qhov nyuaj, uas muaj feem ntau yuav ua rau kom tawg ntawm cov kab mob thiab hloov qhov ruaj khov ntawm oxide txheej. Kev sib txhuam me ntsis yuav ua rau muaj qhov sib txawv ntawm kev puas tsuaj rau cov zaj duab xis passivation tsim ntawm titanium nto. Piv txwv li, nyob rau hauv ib qho chaw tsis muaj oxygen, kev ruaj ntseg ntawm cov oxide txheej tsis muaj zog. Thaum puas lawm, nws tsis tuaj yeem kho tam sim ntawd lossis txheej txheej oxide tshiab tuaj yeem tsim, ua rau nws yooj yim dua ua rau corrosion. Qhov xwm txheej no yuav luag tsis pom thaum rov ua dua ntawm tib neeg lub cev thiab siv cov cuab yeej siv. Yas deformation yuav hloov cov txheej txheem ntawm cov khoom, yog li cuam tshuam rau corrosion ntawm cov khoom. Cov qib sib txawv ntawm cov yas deformation muaj qhov sib txawv heev ntawm cov khoom siv corrosion ntawm cov khoom. Thaum lub sij hawm cov txheej txheem yas deformation, kev ntxhov siab sab hauv yog concentrated, ua rau muaj kev cuam tshuam hauv kev sib tshuam thiab cov nplej. Yog li ntawd, yas deformation tsis muaj zog corrosion kuj ntawm cov khoom.
Titanium corrosion mechanism
Titanium yog ib qho kev hloov pauv ntawm Pawg IVB. Cov khoom siv tshuaj lom neeg yog cov nquag nquag thiab muaj kev sib raug zoo nrog oxygen. Nyob rau hauv ib qho nruab nrab uas muaj cov pa oxygen, ib zaj duab xis ntom ntom tau yooj yim tsim rau ntawm titanium nto. Qhov no passivation zaj duab xis yog nyias nyias, nrog ib tug tuab feem ntau xws li los ntawm ob peb nanometers mus rau kaum nanometers. Lub hav zoov ntawm titanium alloy passivation zaj duab xis txo qhov chaw ntawm qhov chaw ua haujlwm tawg thiab ua kom qeeb ntawm qhov tawg, yog li tiv thaiv kev puas tsuaj los ntawm kev tawg. Tsis tas li ntawd, cov zaj duab xis passivation tuaj yeem kho tau thiab cov yeeb yaj kiab tiv thaiv tshiab tuaj yeem tsim sai sai thaum puas. Yog li ntawd, titanium muaj zoo corrosion kuj. Cov ntaub ntawv corrosion ntawm titanium hlau implanted nyob rau hauv cov kab mob yuav muab faib ua pitting corrosion, kev nyuaj siab corrosion, crevice corrosion, galvanic corrosion thiab hnav corrosion.
Kev ntxhov siab corrosion yog hais txog qhov tshwm sim ntawm cov hlau tawg thaum lub zog tensile thiab corrosion ua ib txhij. Cov txheej txheem dav dav yog: qhov kev txiav txim ntawm tensile kev ntxhov siab ua rau cov yeeb yaj kiab tiv thaiv tsim ntawm cov hlau nto pib tawg, ua rau tawg qhov chaw ntawm pitting corrosion los yog crevice corrosion, uas tsim ntxaum. Nyob rau tib lub sijhawm, qhov kev txiav txim ntawm tensile kev ntxhov siab yuav ua rau cov yeeb yaj kiab tiv thaiv kom tawg ntau zaus, tsim cov kab nrib pleb perpendicular mus rau cov kev taw qhia ntawm tensile stress. Kev tawg lossis tawg.
Cov yam ntxwv cuam tshuam kev ntxhov siab corrosion ntawm titanium alloys
Qhov tshwm sim ntawm titanium alloy SCC yog qhov tshwm sim ntawm kev sib cuam tshuam ntawm peb yam: ib puag ncig, kev ntxhov siab thiab khoom siv. SCC yog kev xaiv heev. Tsuav yog ib qho ntawm peb yam saum toj no hloov, SCC yuav tsis tshwm sim.
Titanium alloys tej zaum yuav raug kev nyuaj siab corrosion cracking nyob rau hauv qhov kev txiav txim ntawm ntau yam xov xwm xws li aqueous tov, distilled dej, organic tov, ntsev kub, thiab lwm yam SCC mechanisms nyob rau hauv txawv media yog txawv.
Tseem muaj qhov sib txawv loj hauv kev cuam tshuam ntawm pH tus nqi ntawm titanium alloy SCC. Feem ntau hais lus, raws li tus nqi pH nce, SCC rhiab heev ntawm titanium alloys txo. Thaum tus nqi pH yog 13-14, SCC feem ntau tuaj yeem cuam tshuam. Txawm li cas los xij, nyob rau hauv pem hauv ntej ntawm cov kab nrib pleb hauv zos qhov twg SCC hloov, ib puag ncig muaj zog corrosive nrog tus nqi pH ntawm 2 txog 3 kuj tseem tuaj yeem tsim.
Kev cuam tshuam ntawm hluav taws xob muaj peev xwm ntawm qib SCC yog qhov tseem ceeb. Cov txheej txheem corrosion tsim los ntawm cov alloys thiab cov xov xwm sib txawv, thiab lawv cov SCC rhiab heev muaj peev xwm kuj txawv. Piv txwv li, nyob rau hauv B-titanium alloys nyob rau hauv aqueous tov uas muaj halides, SCC nce thaum lub peev xwm nyob ib ncig ntawm -600mV; Cov kab nrib pleb kuj yuav tshwm sim ntawm qhov muaj peev xwm dhau-passivation; tab sis ntawm qhov muaj peev xwm qis dua -1000mV, yuav tsis muaj qhov tawg. tawg. Hauv cov tshuaj aqueous uas muaj Cl- thiab Br-, SCC rhiab heev ntawm Ti8Al1Mo1V yog -500mV{{10}}mV. Hauv cov tshuaj aqueous uas muaj I-, qhov chaw muaj peev xwm nkag siab yog siab dua 0mV.
Qhov kub thiab txias yog ib qho tseem ceeb cuam tshuam qhov tshwm sim ntawm SCC hauv titanium alloys. Feem ntau, thaum kub nce, qhov susceptibility ntawm SCC nce. Nyob rau hauv ib puag ncig kub ntsev ntawm {{0}} degree, qhov kev nyuaj siab corrosion ntawm Ti6Al3Mo2Zr0.5Sn alloy yog rhiab heev rau SCC saum 450 degree. Lub SCC rhiab heev ntawm Ti6Al4V alloy nrog ib tug npaum li cas ntawm Pd los yog Mo ntxiv nyob rau hauv H2S CO2 NaCl S tov ntawm 200 degree yog tsawg tshaj li ntawm 250 degree. Txawm li cas los xij, cov khoom siv cog rau hauv tib neeg lub cev muaj qhov tsis txaus siab rau qhov kub thiab txias.
When the medium is in the gap formed between the metal component and the metal or non-metal, it can accelerate the corrosion of the metal in the gap, which is called crevice corrosion. Crevice corrosion is a type of localized corrosion. When there are gaps in titanium and titanium alloys, due to the lack of oxidized substances in the gaps, they become anodes and corrode, destroying the passivation film. Generally, crevice corrosion goes through three stages: ① The consumption of oxygen in the crevice; ② The formation of macro cells and the reduction of pH value; ③ The passivation film is activated and dissolved until it is completely destroyed. The study found that in Hanks solution at 37°C, the crevice corrosion degree of the materials in descending order is: NiTi>NiTiCu>316L>Ti6Al4V≈Ti; Ti thiab Ti6AI4V muaj zog crevice corrosion kuj nyob rau hauv Hanks tov. .
Hnav corrosion yog thaum hlau los rau hauv kev sib cuag nrog nruab nrab, tus txheeb ze txav ceev yog loj, ua rau cov hlau nto yuav tsum tau hnav, uas nyob rau hauv lem ua kom ceev corrosion ntawm hlau. Thaum titanium yog cog raws li kev cog qoob loo, nws yuav hnav rau qee yam nrog cov cuab yeej phais, ua rau cov oxide zaj duab xis uas twb muaj lawm ntawm qhov chaw raug puas tsuaj. Yog hais tias cov oxide zaj duab xis no tsis tuaj yeem kho tau raws sijhawm, cov hlau implanted yuav ntxiv corrode los yog ua tsis tiav.
Biomedical cov ntaub ntawv yog cov ntaub ntawv tseem ceeb rau kev loj hlob sai ntawm kev kho mob niaj hnub thiab yog lub ntsiab lus tseem ceeb ntawm cov ntaub ntawv tshawb fawb nyob rau hauv lub xyoo pua 21st. Titanium tau ua tiav zoo raws li cov khoom siv corrosion-resistant tshiab thiab yog dav siv hauv biomedical teb vim nws zoo biocompatibility thiab corrosion kuj. Txawm li cas los xij, tseem muaj ntau yam teeb meem uas yuav tsum tau daws rau kev siv titanium hauv tib neeg ib puag ncig. Yog li ntawd, nws yog ib qho tsim nyog yuav tsum tau ua qhov kev tshawb fawb tob txog ntau yam ntawm cov khoom ntawm titanium cov ntaub ntawv los tsim thiab pib txhim kho sai ntawm cov ntaub ntawv biomedical.
xa mus rau:
[1] Qin Ying, Wang Shaoan. Kev tshawb fawb txog kev txhim kho corrosion ntawm titanium thiab titanium alloy hniav cog hniav [J]. International Journal of Oral Medicine, 2008, 35(4): 255-258.
[2] Huang Yongguang. Titanium alloy cov ntaub ntawv rau kev phais implantation thiab lawv standardization [J]. Kev nce qib hauv Titanium Kev Lag Luam, 2002, (1): 36-39
