Rau Titanium Sheath rhaub uas muaj qee zaus qhuav-Tawm (10 feeb hauv ib lub lis piam) Hauv 5% Sulfuric Acid Tank, Dab tsi yog Qhov Ntau Tshaj Ntawm Qhov Qhuav -Tom Tawm Ua Ntej Oxide Spalls Thiab Tube Thins Ntau dhau?
Tso lus
Nyob rau hauv 5% sulfuric acid (H₂SO₄) ntawm 80 degree, titanium cia siab rau ib tug passive oxide zaj duab xis rau kev tiv thaiv. Qee zaus qhuav- tawm- thaum cov kua theem poob qis hauv qab lub rhaub- tso cov titanium kub rau huab cua. Qhov kub ceev ceev (los ntawm 80℃mus rau ntau tshaj 200 degree) ua rau thermal expansion mismatch ntawm oxide nplai thiab hlau, ua rau spalling. Txhua qhov qhuav- tawm qhov tshwm sim tshem tawm ib txheej nyias ntawm oxide thiab qee cov hlau hauv paus. Tom qab kwv yees li 50 qhuav-tawm cov txheej xwm, cov txheej txheem sib sau ua ke nce mus txog 0.1–0.2 mm. Tom qab 200 txheej xwm, perforation ntawm 1.2 hli phab ntsa yuav tshwm sim. Qhov siab tshaj plaws ntawm qhuav-tawm cov txheej xwm ua ntej ntau dhau thinning thiab perforation nyob ntawm lub sij hawm ntawm txhua qhov qhuav - tawm kev tshwm sim thiab cov kua qaub concentration.
Lub Mechanism ntawm Oxide Spalling thiab Hlau Poob Thaum Qhuav -Tawm
Thaum lub sijhawm ua haujlwm ib txwm nyob ntawm 80 degree, titanium oxide nplai yog nyias (2-5 nm) thiab tiv thaiv. Thaum cov kua dej poob qis thiab lub tshuab cua sov tau raug huab cua, qhov kub ntawm qhov kub nce mus rau 200-400℃hauv feeb. Cov oxide loj hlob sai mus rau 0.5-2 µm. Lub thermal expansion mismatch ntawm oxide (=7-8 × 10⁻⁶ /℃) thiab titanium hlau (=8.6 × 10⁻⁶ /℃) tsim tensile stresses nyob rau hauv oxide thaum txias. Tom qab immersion tom ntej, thermal shocks tawg thiab spills cov oxide. Txhua qhov tshwm sim spalling tshem tawm 2-10 µm ntawm cov oxide thiab ib txheej nyias (1-5 µm) ntawm cov hlau hauv qab. Cov xwm txheej rov ua dua ua rau muaj kev sib sau ua ke.
Quantitative Thinning as a Function of qhuav-Tawm Txheej xwm
Kev tswj xyuas hauv 5% H₂SO₄ ntawm 80℃nrog 10-feeb feeb- tawm cov xwm txheej tau tsim cov hlau poob rau Qib 2 titanium. Thaum 0 qhuav-tawm txheej xwm (tsis qhuav tawm), phab ntsa thickness tseem nyob ntawm 1.20 hli, cov oxide tsis zoo, thiab tsis muaj hlau poob. Ntawm 10 qhov xwm txheej, cov hlau tsis sib xws yog 0.02-0.05 hli, cov phab ntsa ntxiv yog 1.15-1.18 hli, thiab qhov me me spalling yog pom. Ntawm 25 qhov xwm txheej, qhov poob yog 0.05-0.10 hli, cov phab ntsa seem yog 1.10-1.15 hli, thiab qhov nruab nrab spalling tshwm sim. Ntawm 50 txheej xwm, qhov poob yog 0.10-0.20 hli, qhov seem phab ntsa yog 1.00-1.10 hli, thiab tseem ceeb thinning yog tam sim no. Ntawm 100 qhov xwm txheej, qhov poob yog 0.20-0.40 hli, cov phab ntsa ntxiv yog 0.80-1.00 hli, thiab hnyav thinning yuav tsum tau kuaj xyuas. Ntawm 200 txheej xwm, qhov poob yog 0.40-0.80 hli, cov phab ntsa ntxiv yog 0.40-0.80 hli, thiab perforation txaus ntshai. Ntawm 500 txheej xwm, qhov poob yog 1.00-2.00 hli, thiab lub raj yog perforated.
Kev cuam tshuam ntawm Acid Concentration thiab Qhuav -Tawm Lub Sij Hawm ntawm Hlau Loss
Cov hlau poob ib qho qhuav- tawm qhov tshwm sim nce nrog acid concentration thiab qhuav -tawm sijhawm. Ntawm 5% H₂SO₄ nrog 5- feeb qhuav- tawm, cov hlau poob rau ib qho kev tshwm sim yog 2-4 µm, thiab 125-250 qhov xwm txheej yuav tsum tau poob 0.5 hli. Ntawm 5% H₂SO₄ nrog 10- feeb qhuav- tawm, qhov poob yog 4–8 µm ib qhov xwm txheej, thiab 60–125 qhov xwm txheej ua rau poob 0.5 mm. Ntawm 5% H₂SO₄ nrog rau 30- feeb qhuav tawm, qhov poob yog 8–15 µm rau ib qho xwm txheej, thiab 30–60 txheej xwm ua rau poob 0.5 mm. Ntawm 10% H₂SO₄ nrog 10-feeb qhuav-tawm, qhov poob yog 6-12 µm rau ib qho xwm txheej, thiab 40-80 txheej xwm ua rau poob 0.5 hli. Ntawm 20% H₂SO₄ nrog 10-feeb qhuav-tawm, qhov poob yog 10-20 µm rau ib qho xwm txheej, thiab 25-50 txheej xwm ua rau poob 0.5 hli.
Qhuav-Tau Kev Tswj Xyuas thiab Phau Ntawv Qhia Txog Kev Ua Neej
Cov lus hauv qab no muab qhov siab tshaj plaws uas tso cai rau qhuav-tawm txheej xwm rau Qib 2 titanium rhaub hauv 5% H₂SO₄ ntawm 80 degree, raws li cov phab ntsa tuab tom qab thinning.
| Number of qhuav-Tawm Txheej xwm (10 feeb txhua) | Phab ntsa seem Thickness (mm) | Cov hlau poob (mm) | Pom zoo ua | Kev Pabcuam Tseem Ceeb ntawm 0.05 hli / xyoo Corrosion |
|---|---|---|---|---|
| <10 | >1.15 | <0.05 | Kev ua haujlwm li qub | >20 xyoo |
| 10–25 | 1.10–1.15 | 0.05–0.10 | Tshawb xyuas txhua xyoo | 15-20 xyoo |
| 25–50 | 1.00–1.10 | 0.10–0.20 | Tshawb xyuas peb lub hlis twg | 10-15 xyoo |
| 50–100 | 0.80–1.00 | 0.20–0.40 | Npaj hloov hauv 2 xyoos | 5-10 xyoo |
| 100–200 | 0.40–0.80 | 0.40–0.80 | Hloov tam sim ntawd | <5 years |
| >200 | <0.40 | >0.80 | Perforated | Ua tsis tiav |
Engineering Beyond Dry-Tau qhov xwm txheej suav
Qib titanium cuam tshuam rau spalling kuj. Qib 7 (palladium{2}}stabilized) tsim cov oxide ntau dua, txo cov hlau poob rau ib qho kev tshwm sim los ntawm 30–50%. Qib 12 muaj kev txhim kho nruab nrab. Phab ntsa thickness ncaj qha txiav txim tus naj npawb ntawm cov xwm txheej rau perforation; phab ntsa 2.0 mm tuaj yeem zam tau ob zaug ntau qhov xwm txheej raws li phab ntsa 1.0 mm. Lub tswb qis- theem qis tau teeb tsa ntawm 20% saum lub rhaub qhov siab tiv thaiv kom qhuav - tawm cov xwm txheej tag nrho. Lub tshuab refill tsis siv neeg tswj cov kua theem. Yog tias qhuav- tawm tsis tuaj yeem zam tau, lub rhaub dej yuav tsum tau muab tua tam sim ntawd thaum cov kua dej poob los tiv thaiv qhov kub thiab txias uas ua rau muaj qhov sib txawv.
Ua ib qho kev qhia tshwj xeeb
Rau lub titanium sheath heater hauv 5% sulfuric acid ntawm 80℃qhov twg qee zaus qhuav- tawm tsis tuaj yeem tiv thaiv, txwv qhov sib xyaw qhuav- tawm cov xwm txheej rau 50 ua ntej hloov lub rhaub. Nruab lub tswb qis- theem qis ntawm 20% siab tshaj qhov siab ntawm lub tshuab cua sov thiab lub tshuab tsis siv neeg rov ua kom tsis txhob qhuav- tawm. Yog tias qhuav-tawm tshwm sim, tua lub rhaub hauv 1 feeb kom txo qis thermal shock. Rau cov cua sov uas twb muaj lawm uas tau ntsib ntau dua 50 qhuav-tawm txheej xwm, ntsuas phab ntsa thickness ultrasonically ntawm qhov chaw feem ntau raug rau qhuav-tawm (feem ntau yog saum 100 hli). Yog tias cov phab ntsa seem qis dua 1.0 hli, hloov lub rhaub. Los ntawm kev tswj tus naj npawb ntawm qhuav- tawm cov xwm txheej thiab cov lus teb rau lawv, tus kws tshaj lij tiv thaiv kev ua kom thinning ntau dhau thiab perforation ntawm titanium heaters hauv sulfuric acid kev pabcuam.
