Rau Titanium Immersion rhaub hauv 5% Sodium Persulfate Solution ntawm 50 degree, Vim li cas Persulfate Ion tsis Passivate titanium txawm tias nws yog ib qho muaj zog Oxidizer, thiab hloov ua Transpassive Dissolution?

Sodium persulfate (Na₂S₂O₈) yog ib qho muaj zog oxidizing tus neeg sawv cev, nrog tus qauv txo qhov peev xwm rau S₂O₈²⁻ / SO₄²⁻ ntawm 2.01 V, uas siab dua li ntawm nitric acid. Nyob rau hauv cov ntaub ntawv ntawm titanium, persulfate induces transpassive dissolution es tsis tu ncua passivation. Ntawm 50℃C, qhov muaj zog oxidation muaj peev xwm txav cov titanium nto rau hauv qhov chaw transpassive saum toj no 1.8 V vs cov pa hydrogen electrode, qhov twg cov txheej txheem passive lov thiab titanium yaj li Ti 4 + ntawm tus nqi ntawm 0.2-0.5 hli ib xyoo. Lub transpassive dissolution yog uniform, tsis pitting. Tab sis tus nqi corrosion yog siab dhau rau ntau daim ntawv thov.

Mechanism ntawm Transpassive Dissolution Induced los ntawm Persulfate

Titanium muaj qhov chaw ruaj khov nyob nruab nrab ntawm kwv yees li 0 V thiab 1.8 V. Ntawm qhov muaj peev xwm siab dua 1.8 V zaj duab xis TiO2 yog oxidized rau soluble Ti 4 + hom: TiO2 + 2H2O → Ti 4 + + 4OH - + 2e - . Lub peev xwm ua ke ntawm titanium nyob rau hauv persulfate heev.7-2. Nyob rau hauv cov cheeb tsam no lub transpassive dissolution tam sim no loj. Corrosion yog uniform raws li tag nrho cov saum npoo yog nyob rau hauv lub transpassive cheeb tsam. Tsis muaj qhov sib tsoo hauv cheeb tsam tshwm sim tsis tau muaj qhov cuam tshuam tas li ntawm zaj duab xis.

Persulfate Concentrations Quantitative Corrosion Rate raws li kev ua haujlwm ntawm

Nyob rau hauv cov ntaub ntawv ntawm Qib 2 titanium, cov hauv qab no tau tsim nyob rau hauv kev tswj xyuas hauv sodium persulfate ntawm 50℃rau 500 teev. Ntawm 0% persulfate (baseline) tus nqi corrosion yog 0.005-0.010 mm / xyoo, lub peev xwm nto yog 0.2-0.5 V thiab cov txheej txheem yog passive. 1% persulphate 0.05-0.12 mm/y 1.2-1.5 V Mixed 3% Potential.2-xyoo Rate. 1.5-1.7 V Mechanism Transpassive pib Thaum 5% persulfate, tus nqi yog 0.20-0.40 mm / xyoo, lub peev xwm yog 1.7-1.9 V, thiab lub mechanism yog transpassive. Tus nqi yog 0.35-0.60 mm / xyoo ntawm 10% persulfate, lub peev xwm yog 1.8-2.0 V thiab cov txheej txheem yog transpassive hnyav.

Kub cuam tshuam rau kev hloov pauv hloov pauv

Ntawm qhov kub siab dua, thaj tsam transpassive hloov mus rau qhov muaj peev xwm qis dua. Tus nqi corrosion yog transpassive thiab yog 0.10-0.20 mm / xyoo ntawm 25℃thiab 5% persulfate. Nws loj hlob 0.15-0.30 hli hauv ib xyoos ntawm 40 degree. Tus nqi yog 0.20-0.40 mm / xyoo ntawm 50 degree. Tus nqi yog 0.30-0.60 hli hauv ib xyoos ntawm 60 degree. Tus nqi yog ntau tshaj 0.50 hli / xyoo siab tshaj 70 degree. Qhov siab dua qhov kub, qhov hnyav dua yog qhov transpassive dissolution.
** Phau ntawv qhia txog kev xaiv cov khoom hauv Persulfate Service

Cov lus hauv qab no muab cov lus pom zoo rau cua sov ntawm kev daws teeb meem ntawm sodium persulphate raws li qhov xav tau thiab kub.

Persulfate Concentration (%) Kub (degree) Qib 2 Corrosion Rate (mm/xyoo) Corrosion Rate (mm/xyoo) Qib 7 Cov khoom pom zoo<1 50 0.05–0.10 0.03–0.06 Grade 7 with thick wall 1–3 40 0.08–0.15 0.05–0.10 PTFE-coated titanium 1–3 50 0.12–0.25Not recommended for titanium 3–5 30 0.10–0.20 0.06–0.12 Tantalum or PTFE >5 Any >0.20 >0.12 Tantalum los yog PTFE
Titanium thiab Beyond Engineering xaiv

Lub transpassive dissolving tus nqi ntawm Qib 7 yog me ntsis qis dua Qib 2 (30-50% txo) vim palladium enrichment, tab sis qhov kev txhim kho tsis txaus los ua titanium tsim nyog rau kev pabcuam persulfate. Phab ntsa thickness yog muab rau kev tiv thaiv corrosion. Nrog 2.0 hli phab ntsa thiab 0.20 hli ib xyoo corrosion, phab ntsa yuav ua siab ntev 10 xyoo tab sis qhov no yog negligible. PTFE coated titanium heaters muab kev tiv thaiv zoo thiab ua kom cov hlau cais tawm ntawm cov tshuaj persulfate. Tantalum nthuav tawm ntau qhov ntau dua passive thiab yog persulfate resistant. Zirconium kuj ua haujlwm zoo, tab sis nws kim heev.

Specification Kev ntseeg siab

Tus kwv yees corrosion tus nqi rau titanium immersion rhaub hauv 5% sodium persulfate ntawm 50℃yog 0.20-0.40 hli ib xyoo, uas yog siab dhau rau kev siv ntev. Siv PTFE coated titanium rhaub los yog tantalum rhaub . 0.5 hli PTFE Phab ntsa thickness yuav tsum yog 2,5 hli, yog tias xav tau titanium, cov persulfate concentration yuav tsum tau khaws cia ntawm 2%, thiab kub ntawm 40 degree. Txheeb xyuas lub ntsuas cua kub ib xyoos ib zaug hauv kev ua haujlwm. Thaum lub thickness ntawm phab ntsa yog 1.0 hli, hloov lub rhaub. Paub tias persulfate yog ib qho transpassive dissolver thiab tsis yog passivator, tus engineer xaiv cov khoom tsim nyog rau qhov chaw oxidizing hnyav.