Qhov Kev Tsis Txaus Siab rau Titanium's Corrosion Resistance
Titanium lub koob npe nrov yog corrosion- hlau resistant yog zoo-deserved thoob plaws ntau yam ntawm cov tshuaj ib puag ncig, los ntawm seawater thiab chloride brines mus rau oxidizing acids thiab alkaline daws. Txawm li cas los xij, qhov ncaj qha immersion ntawm titanium rhaub hauv cov roj chlorine ntub yog qhov tshwj xeeb thiab txaus ntshai rau qhov kev ua tau zoo tshaj plaws. Kev sib xyaw ua ke ntawm cov roj chlorine, noo noo, thiab kub siab ua rau muaj kev puas tsuaj rau cov tshuaj tiv thaiv titanium, ua rau cov hlau poob sai, ignition, lossis ob qho tib si. Qhov kev coj cwj pwm no cuam tshuam qhov kev cia siab ntawm qhov xav tau raws li titanium tsis kam rau cov tshuaj chlorine aqueous thiab tau coj mus rau ntau qhov kev lag luam siab -profile qhov xwm txheej uas cov khoom siv titanium tau yuam kev rau cov kev pabcuam roj chlorine ntub dej. Qhov kev tshuaj ntsuam no tshuaj xyuas cov tshuaj thiab cov thermodynamic hauv paus rau titanium qhov tsis sib haum nrog cov tshuaj chlorine ntub dej, ntsuas cov xwm txheej hauv qab qhov hluav taws xob thiab kev xeb sai sai, thiab muab cov lus qhia meej rau cov engineers kom tsis txhob muaj daim ntawv thov txaus ntshai no.
Lub Chemical Basis rau Titanium's Vulnerability rau Wet Chlorine
Kev sib cuam tshuam ntawm titanium thiab cov roj chlorine ntub dej tau los ntawm cov tshuaj tiv thaiv uas yog qhov sib txawv ntawm qhov kev tiv thaiv tsis zoo uas pom hauv cov tshuaj chlorine aqueous. Nyob rau hauv lub xub ntiag ntawm noo noo, chlorine gas hydrolyzes tsim hydrochloric acid thiab hypochlorous acid raws li cov tshuaj tiv thaiv Cl₂ + H₂O → HCl + HOCl. Cov hydrochloric acid uas ua los ntawm hydrolysis no tawm tsam cov titanium dioxide passive zaj duab xis, hloov mus rau soluble titanium chlorides thiab nthuav tawm cov hlau hauv qab. Cov titanium raug ces reacts ncaj qha nrog chlorine gas nyob rau hauv ib tug exothermic cov tshuaj tiv thaiv uas yuav ua tau nws tus kheej-sustaining: Ti + 2Cl₂ → TiCl₄, nrog ib tug kub ntawm cov tshuaj tiv thaiv ntawm kwv yees li 600 kJ / mol. Cov khoom lag luam titanium tetrachloride yog cov kua dej tsis haum uas evaporates los ntawm qhov chaw, tsis tu ncua nthuav tawm cov titanium tshiab rau cov chlorine cua. Cov tshuaj tiv thaiv tus nqi yog kub heev-nyob ntawm, accelerating exponentially raws li kub nce. Ntawm qhov kub siab tshaj 100 degree, cov tshuaj tiv thaiv maj mam, nrog corrosion tus nqi ntawm 0.1-0.5 mm / xyoo. Ntawm qhov kub siab tshaj 200 degree, cov tshuaj tiv thaiv sai sai, nrog rau corrosion ntau tshaj 10 hli / xyoo. Tshaj li 300 degree, cov tshuaj tiv thaiv tuaj yeem ua rau nws tus kheej txhawb nqa, nrog rau cov cua sov tsim los ntawm cov tshuaj tiv thaiv kom sov thiab ua rau cov titanium hlawv hauv cov chlorine cua. Cov tshuaj tiv thaiv combustion no ua rau cov nplaim dawb ci ntsa iab thiab tso tawm titanium tetrachloride vapor, uas cuam tshuam nrog huab cua noo kom tsim cov pa taws dawb ntawm titanium oxide thiab hydrochloric acid.
Cov xwm txheej uas ua rau muaj kev puas tsuaj loj
Cov xwm txheej xav tau rau kev puas tsuaj titanium tsis ua haujlwm hauv cov roj chlorine ntub dej yog qhov zoo - txhais thiab nyob ntawm qhov ntsuas kub, chlorine concentration, thiab cov dej noo. Cov ntsiab lus noo noo yog qhov tseem ceeb tshaj qhov sib txawv; ntawm cov dej noo qis dua 0.05%, cov tshuaj tiv thaiv hydrolysis tsis txaus los tsim kom muaj hydrochloric acid txaus los ua kom tsis muaj zog ntawm cov yeeb yaj kiab, thiab titanium nthuav tawm tsim nyog tiv thaiv mus txog 150 degree. Txawm li cas los xij, ntawm cov dej noo siab tshaj 0.1%, tus nqi corrosion nce ntau, tshwj xeeb tshaj yog nyob rau qhov kub siab. Qhov kub ntawm cov titanium nto, uas yog siab tshaj qhov kub ntawm cov roj vim yog cov cua kub nkag los ntawm lub rhaub dej kub, yog qhov kev tswj qhov sib txawv rau qhov kev loj hlob ntawm qeeb corrosion mus rau ignition. Thaum kub txog li 150 degree, cov tshuaj tiv thaiv tseem tswj tau, txawm hais tias tus nqi corrosion kuj yog qhov tsis txaus ntseeg. Nyob nruab nrab ntawm 150℃thiab 250 degree, cov tshuaj tiv thaiv nrawm thiab qhov chaw yuav npog nrog cov txheej txheem tiv thaiv ntawm titanium oxychlorides thiab titanium dioxide. Ntawm qhov kub siab tshaj 250 degree, cov tshuaj tiv thaiv nce mus rau qhov chaw uas cov cua sov tsim ntau tshaj li cua sov dissipation, thiab titanium undergoes thermal runaway rau ignition. Lub xub ntiag ntawm cov kab mob ntawm cov titanium nto, tshwj xeeb tshaj yog cov organic residues los yog hlau hais, tuaj yeem txo qhov kub ntawm qhov hluav taws kub los ntawm kev muab cov chaw ua haujlwm rau chlorine adsorption thiab cov tshuaj tiv thaiv pib.
Synthesizing the Trade-tawm: Phau Ntawv Qhia Kev Pabcuam Kev Ua Haujlwm
Kev siv cov titanium rhaub hauv cov roj chlorine ntub dej yog feem ntau contraindicated, tab sis tej yam kev mob yuav tso cai txwv tsis pub siv. Cov nram qab no xaiv matrix muab kev taw qhia rau cov txheej txheem engineers.
| Cov xwm txheej ua haujlwm | Feasibility ntawm Titanium | Cov ntsiab lus tseem ceeb thiab kev txwv kev ua haujlwm nyab xeeb |
|---|---|---|
| Qhuav Chlorine (< 0.05% H₂O), Temperature < 100°C | Ua tau | Cov dej noo tsawg tiv thaiv hydrolysis. Titanium tuaj yeem siv nrog ceev faj saib xyuas cov dej noo. |
| Wet Chlorine (>0.1% H₂O), Kub <100 degree | Txwv tsis pub | Corrosion tus nqi yog 0.5-1.0 hli / xyoo. Kev pabcuam lub neej yog txwv rau 2-3 xyoos nrog cov phab ntsa tuab thiab nquag hloov. |
| Wet Chlorine (>0.1% H₂O), Kub 100-150 degree | Tsis pom zoo | Corrosion tus nqi siab tshaj 3 hli / xyoo. Kev pabcuam lub neej ntsuas hauv lub hlis tsis yog xyoo. |
| Wet Chlorine (>0.1% H₂O), Kub> 150 degree | Txwv tsis pub | Muaj kev pheej hmoo ntawm thermal runaway ignition. Kev nyab xeeb ntawm cov neeg ua haujlwm muaj kev pheej hmoo loj. |
| Chlorine nrog Organic Contaminants | Txwv tsis pub | Cov organic tebchaw nrog cov tshuaj chlorine los tsim cov carbonaceous deposits uas ignite ntawm qis kub. |
Engineering Beyond Avoidance: Cov Khoom Siv Muaj Kev Nyab Xeeb Lwm Cov Khoom Siv rau Cov Khoom Siv Dej chlorine
Thaum cov roj chlorine ntub dej yuav tsum tau ua kom sov, lwm cov ntaub ntawv yuav tsum tau xaiv uas haum rau qhov hnyav. Iav- cov cua kub cua sov muab cov tshuaj tiv thaiv zoo rau cov chlorine ntub dej txog li 150 degree, nrog rau cov iav saum npoo yog inert kiag li rau chlorine thiab hydrochloric acid. Txawm li cas los xij, iav- cov khoom siv lined yog txwv rau cov cua sov qis vim yog thermal conductivity ntawm iav txheej. Silicon carbide immersion heaters muaj lwm txoj hauv kev, nrog cov tshuaj tiv thaiv rau cov chlorine ntub dej txog 300℃thiab siab thermal conductivity. Silicon carbide kuj tseem tiv taus thermal poob siab, ua rau nws tsim nyog rau kev siv nrog caij tsheb kauj vab kub. Tantalum heaters muab cov qib siab tshaj plaws ntawm kev tiv thaiv corrosion rau cov chlorine ntub dej, tsis muaj kev txwv qhov kub thiab txias hauv cov tshuaj chlorine. Tus nqi siab ntawm tantalum, txawm li cas los xij, txwv tsis pub nws siv rau cov ntawv thov tseem ceeb tshaj plaws uas lwm cov ntaub ntawv tsis tsim nyog. Kev siv cov tshuaj chlorine qhuav los ntawm kev tshem tawm cov dej noo los ntawm cov kwj dej yog qhov kev daws teeb meem zoo tshaj plaws, vim qhov no tshem tawm qhov teeb meem sib haum nrog titanium. Kev siv lub tshuab cua sov titanium nyob rau hauv ib puag ncig chlorine qhuav, nrog rau kev saib xyuas cov dej tsis tu ncua thiab tsis siv neeg kaw ntawm qhov ntsuas dej noo, yog ib txoj hauv kev ua tau rau qee qhov kev siv. Kev tsim kom muaj kev soj ntsuam nruj thiab hloov lub sijhawm, nrog rau kev nyab xeeb ntawm kev ua haujlwm kub ntawm 120 degree, muab txoj hauv kev zoo rau cov xwm txheej uas yuav tsum tau siv titanium.
Xaus: Ib qho kev txwv nruj rau feem ntau cov kev pabcuam
Kev tso dej ncaj qha ntawm titanium rhaub hauv cov roj chlorine ntub dej yog qhov kev coj ua uas ua rau muaj kev pheej hmoo tsis txaus ntseeg rau feem ntau cov ntawv thov. Kev tsom xam pom tau tias hydrolysis ntawm chlorine nyob rau hauv lub xub ntiag ntawm noo noo generates hydrochloric acid uas tawm tsam cov titanium passive zaj duab xis, ua rau kom ceev corrosion uas yuav nce mus rau thermal khiav thiab ignition. Los ntawm kev nkag siab txog cov xwm txheej uas ua rau tus cwj pwm tsis zoo no thiab xaiv cov khoom siv los yog siv cov txheej txheem hloov kho uas tshem tawm cov kev pheej hmoo, cov txheej txheem engineers tuaj yeem ua kom muaj kev nyab xeeb thiab txhim khu kev qha. Kev xaiv ntawm titanium rau cov kev pabcuam ntub dej chlorine yog qhov kev txiav txim siab uas yuav tsum tau ceev faj ntau, thiab rau cov kev siv feem ntau, kev siv lwm cov ntaub ntawv yog qhov kev kawm nkaus xwb.
