Lub zog Acidic Chloride Corrosion ntawm Quartz hauv Kub Zinc Chloride Solutions
Zinc chloride (ZnCl₂) yog ntau yam tshuaj siv los ua cov dej hauv kev sib txuas thiab galvanizing (tshem tawm oxide txheej), cov ntoo khaws cia, cov khoom siv hauv cov organic synthesis (Friedel{0}}Cov tshuaj tiv thaiv kab mob), thiab cov electrolyte hauv cov roj ntsha qhuav. Cov kev lag luam muaj ntau yam ntawm 50-70% los ntawm qhov hnyav, nrog kev ua haujlwm kub ntawm 60-80 degree. Tsis zoo li cov ntsev nruab nrab, cov ntsiab lus zinc chloride muaj zog acidic vim yog hydrolysis ntau: Zn²⁺ + H₂O ⇌ ZnOH⁺ + H⁺; ZnOH⁺ + H₂O ⇌ Zn(OH)₂ + H⁺. Ib qho 60% ZnCl₂ tov muaj pH ntawm kwv yees li 1.5-2.5 ntawm 25 degree, poob ntxiv ntawm qhov kub siab. Cov kua qaub dawb yog hydrochloric acid (HCl) vim cov anion yog chloride. Yog li, kub concentrated ZnCl₂ tawm tsam quartz los ntawm tib lub tshuab raws li dilute HCl: proton- txhawb nqa hydrolysis ntawm siloxane daim ntawv cog lus, nrog cov tshuaj chloride ions uas muaj peev xwm ua kom nrawm nrawm los ntawm complexation. Qhov kev soj ntsuam no ntsuas seb ZnCl₂ concentration (50-70%), qhov kub thiab txias (60-80 degree), thiab cov kua qaub acidity cuam tshuam rau cov nqi sib txawv ntawm cov fused silica.
Corrosion Kinetics ntawm Fused Silica hauv Kub Zinc Chloride
Qhov corrosion ntawm quartz hauv ZnCl₂ yog tsav los ntawm HCl dawb los ntawm zinc hydrolysis. Ntawm 70℃hauv 60% ZnCl₂, qhov dawb HCl concentration yog kwv yees li 0.1–0.3 M (pH 0.5–1.0). Ntawm no acidity, tus nqi corrosion tsis zoo ntawm quartz yog 0.0003-0.0008 mm / teev. Ntawm 80 degree, tus nqi nce mus rau 0.0006-0.0015 mm / teev. Ntawm 60 degree, tus nqi yog 0.0002-0.0004 mm / teev. Rau kev sib piv, 0.2 M HCl ntawm 70℃corrodes quartz ntawm 0.0005-0.001 mm / teev. Ntawm 70 degree, 2.0 hli quartz sheath yuav poob 0.0006 mm / teev × 3,300 teev=2.0 hli, muab lub neej ntawm kwv yees li 3,300 teev (4.6 hli). A 2.5 hli phab ntsa muab 4,200 teev; ib phab ntsa 3.0 hli muab 5,000 teev.
Lub xub ntiag ntawm cov tshuaj chloride ntau dhau (los ntawm ZnCl₂) tuaj yeem ua kom nrawm nrawm dua li HCl ntshiab ntawm tib pH vim tias chloride ions cuam tshuam rau hydrated silica txheej. Qhov zoo tshaj plaws yog 1.2-1.5 × piv rau HCl ntshiab.
Localized Pitting thiab Deposit Tsim
Zinc chloride cov kev daws teeb meem zoo li tsim cov zinc chloride los yog zinc hydroxide precipitates thaum cua sov los yog evaporation. Cov deposits no yog dawb thiab yuav insulating. Txawm li cas los xij, lawv tsis tshua txhoj puab heev dua li cov deposits ntawm ferric chloride. Lub cheeb tsam meniscus yog qhov yooj yim rau crystallization.
Yuav Ua Li Cas Phab Ntsa Thickness Hloov Kev Pabcuam Lub Neej
Lub neej scales linearly nrog phab ntsa thickness. Rau kev pabcuam txuas ntxiv ntawm 70 degree, 2.5-3.0 hli phab ntsa raug pom zoo rau 4-6 lub hlis hloov pauv.
Thermal Penalty of Thicker Walls
Zinc chloride daws ntawm 60% thiab 70℃muaj thermal conductivity ntawm kwv yees li 0.50-0.55 W / (m·K). U poob los ntawm 427 mus rau 292 W / (m²·K) thaum nce ntawm 1.5 mus rau 3.0 mm, txo qis 32%.
Scenario-Based Xaiv Matrix
| Daim ntawv thov Scenario & Kev khiav hauj lwm Parameters | Pom zoo Phab ntsa Thickness | Cov ntsiab lus tseem ceeb |
|---|---|---|
| Galvanizing flux (60% ZnCl₂, 70 degree, nruam, tu txhua lub lim tiam) | 2.5-3.0mm, qib txheem | Acid corrosion tus nqi ~ 0.0006 hli / teev. Phab ntsa tuab rau 5,000-teev lub neej. U ≈ 350 W / (m²·K). |
| Kev txuag ntoo (50% ZnCl₂, 60 degree, sib tshuam) | 2.0 mm, raws li -kos | Txo qhov kub thiab txias. U ≈ 420 W / (m²·K). |
| Organic synthesis catalyst (70% ZnCl₂, 80 degree, batch) | 3.0mm ib | Siab acidity. Thicker phab ntsa tseem ceeb. |
Complementary Design Modifications:Ntxiv ib qho me me ntawm zinc oxide rau neutralize dawb HCl txo cov corrosion. Qhov cua zoo tshem tawm HCl vapor. Kev tu txhua lub sijhawm nrog dej tshem cov zinc ntsev deposits.
