Thaum lub Titanium Sheath rhaub yog siv los boil ib 5% Sodium Tartrate tov ntawm 103 degree, Vim li cas lub Tartrate Ion Complex Titanium Ions thiab tiv thaiv rov qab, ua rau Uniform Corrosion ntawm 0.2 hli ib xyoo?

Hauv 5% sodium tartrate, tartrate ion (C₄H₄O₆²⁻) yog ib tug muaj zog chelating tus neeg saib xyuas rau titanium ntawm 103℃(boiling). Pitting nres yog tshwm sim los ntawm cov tshuaj chloride thiab fluoride, tab sis tartrate ua rau tsim cov soluble titanium tartrate complexes: Ti⁴⁺ + 3C₄H₄O₆²⁻ → [Ti(C₄H₄O₆)₃]⁴⁻. Lub complexation tshem tawm Ti 4+ ions los ntawm qhov chaw raws li lawv tsim thiab inhibits tsim ntawm ib tug ruaj khov passive zaj duab xis. Yog tsis muaj kev tiv thaiv npog, titanium yuav eroded uniformly ntawm tus nqi tas mus li ntawm 0.15 - 0.25 mm ib xyoos twg uas tsis muaj pitting hauv zos. Corrosion tus nqi tsis yog lub luag haujlwm ntawm lub sijhawm tom qab pib lub sijhawm hloov pauv.

Mechanism ntawm Tartrate-Induced Uniform Corrosion

Lub tartrate ion muaj ntau pawg hydroxyl thiab carboxyl muaj peev xwm tsim tau tsib tus tswv cuab chelate rings nrog Ti 4+ . log K ~ 20).Qhov tsim tas li rau Ti-tartrate complex yog qhov tshwj xeeb tshaj plaws Qhov no txhais tau hais tias txhua Ti⁴⁺ tso tawm los ntawm cov hlau nto yog complexed thiab tam sim ntawd coj mus rau hauv kev daws teeb meem. Cov zaj duab xis passive tsis tuaj yeem loj hlob, vim tias cov khoom solubility ntawm TiO2 tsuas yog dhau ntawm qhov chaw siab heev ntawm Ti4+. Cov txheej txheem corrosion yog raws li qhov ncaj qha dissolving ntawm cov hlau: Ti → Ti⁴⁺ + 4e⁻, ua raws li kev ua kom nrawm nrawm. Vim tias tsis muaj zaj duab xis passive rau hauv zos tawg, cov txheej txheem tsis sib xws.

Quantitative Corrosion Rate piv rau Tartrate Concentration

Cov kev ntsuam xyuas hauv boiling sodium tartrate daws (103 degree) rau 500 hr tau tsim cov hauv qab no rau Qib 2 titanium. Ntawm 0% tartrate (dej ntshiab) tus nqi corrosion yog 0.005-0.010 hli / xyoo, qhov saum npoo yog ci thiab cov txheej txheem yog passive. Ntawm 1% tartrate, tus nqi yog 0.03-0.06 hli ib xyoo, qhov saum npoo qhia pom lub teeb etching thiab cov txheej txheem sib xyaw. Ntawm 3% tartrate tus nqi yog 0.08-0.15 hli / xyoo, qhov saum npoo qhia tau hais tias tsis sib xws etching thiab complexation yog cov txheej txheem dav. Nrog 5% tartrate, tus nqi yog 0.15-0.25 mm / xyoo, nto yog uniform matte tiav, thiab cov txheej txheem yog complexation dominant . 0.20-0.35 mm / xyoo ntawm 10% tartrate, nto tusyees matte, mechanism loj complexation.

Qhov cuam tshuam ntawm pH thiab kub ntawm qhov sib txawv

Tus nqi ntawm complexation thiab corrosion tus nqi yog ib tug muaj nuj nqi ntawm pH thiab kub. Corrosion tus nqi ntawm 60 C, pH 7 thiab 5% tartrate yog 0.04-0.08 mm / xyoo. Tus nqi ntawm 80℃thiab pH 7 yog 0.08-0.15 mm / xyoo. Tus nqi yog 0.15 mus rau 0.25 mm / xyoo ntawm 100℃thiab pH 7. Tus nqi yog 0.10–0.18 mm ib xyoo ntawm 100℃thiab pH 9 (siab dua pH txo corrosion). Tus nqi ntawm 100 degree, pH 5, 0.20-0.35 mm / xyoo (qis pH nce corrosion). Lub zog ua kom muaj zog yog nyob ib ncig ntawm 50 kJ / mol.

Kev tswj ntawm Tartrate Concentration thiab pH hauv Titanium rhaub

Cov lus hauv qab no muab cov kev pom zoo ua haujlwm rau Qib 2 thiab Qib 7 titanium rhaub hauv sodium tartrate daws.

Sodium Tartrate Concentration (%) Kub (degree) pH Qib 2 Corrosion Rate (mm/yr) Corrosion Rate (mm/xyoo) Qib 7 Cov Lus Qhia<1 100 7 0.03–0.06 0.02–0.04 Acceptable 1–3 80 7 0.05–0.10 0.03–0.06 Acceptable 3–5 80 7 0.08–0.15 0.05–0.10 Use Grade 7 3–5 100 7 0.15–0.25 0.10–0.18 Use Grade 7 + thick wall
5-10 100 9 0.10-0.18 0.06-0.12 pH increase >10 Any Any >0.20 >0.12 Tsis pom zoo Engineering Beyond Tartrate Concentration Control

Qib titanium cuam tshuam rau tus nqi complexation. Qib 7 (palladium stabilized) tus nqi corrosion yog 30-50% qis dua cov qib 2 hauv cov kev daws teeb meem tartrate, vim tias palladium ruaj khov txheej txheej nyias nyias txawm tias nyob rau hauv cov xwm txheej nyuaj. Qib 12 qhia tau tias muaj kev txhim kho me ntsis. Phab ntsa tuab muab kev tiv thaiv corrosion . 2 . 0 hli phab ntsa nrog 0 . 15 hli / xyoo zoo corrosion kav 13 xyoo. Nto tiav tsis tshua muaj kev cuam tshuam rau cov corrosion tsis zoo. Los ntawm nce pH mus rau 9 nrog sodium hydroxide tus nqi corrosion yog txo los ntawm 30-40%. Yog hais tias qhov kub thiab txias yog txo los ntawm 100℃mus rau 80 degree, ces tus nqi txiav nyob rau hauv ib nrab.

Tsim ib qho kev qhia tshwj xeeb

Rau lub titanium sheath rhaub lub dominating mechanism yuav tsum tau xav tias yuav tsum tau corrosion kuj nyob rau hauv 5% sodium tartrate ntawm 103 degree. Siv Qib 7 titanium kom txo tus nqi corrosion mus rau 0.10-0.18 hli hauv ib xyoos. Rau kev pab cuam lub neej ntawm 10 mus rau 15 xyoo siv phab ntsa thickness ntawm 2.0 hli. Nce pH rau 9 (yog tias ua tau) nrog sodium hydroxide lossis txo qhov kub kom txog 80C. Thaum lub sij hawm ua hauj lwm, lub thickness ntawm lub rhaub yog saib xyuas los ntawm ultrasonic gauging ib xyoos ib zaug thiab lub rhaub yog hloov thaum lub thickness ntawm phab ntsa mus txog 0.5 hli. Tus engineer paub tias tartrate ions nyuaj rau titanium ions thiab inhibit repassivation, yog li lawv xaiv cov qib zoo thiab phab ntsa tuab kom ntseeg tau tias muaj kev tiv thaiv corrosion.