Tantalum Chemical Properties: Acid Resistance, Ta2O5 Zaj duab xis thiab Alloys
Mar 08, 2024
Chemical Identity thiab Passive Oxide Film
Tantalum yog refractory hloov hlau nrog atomic tooj 73, lub cev -centred cubic lattice, ib tug ceev ntawm txog 16.6-16.7 g / cm³ thiab ib tug melting point ze 2996℃. Nws tshuav nws qhov tseem ceeb ntawm kev lag luam tsis tshua muaj zog dua li chemistry: kev sib koom ua ke, kho tus kheej pentoxide zaj duab xis, Ta₂O₅, tsim nyob rau hauv ib qho chaw huv si raug huab cua lossis noo noo, thiab zaj duab xis no yog vim li cas tantalum muaj sia nyob ib puag ncig uas rhuav tshem cov hlau tsis muaj steel thiab ntau cov nickel alloys. Cov zaj duab xis yog dielectric, chemically inert tshaj ib tug dav muaj peev xwm ntau yam, thiab yuav zus tau tej cov anodically mus rau lub precisely tswj thickness, uas yog lub hauv paus ntawm tantalum capacitor kev lag luam.
Ib txoj hauv kev zoo los xav txog tantalum yog cov hlau uas nws qhov kev ua tau zoo corrosion yog tag nrho cov yeeb yaj kiab - tswj. Txhua yam uas rhuav tshem lossis tiv thaiv zaj duab xis - fluoride ions, kub concentrated alkali, txo qis acidity, lossis oxygen tshaib plab hauv qhov crevice - txhais cov kev txwv ntawm nws cov kev pabcuam. Qhov twg cov zaj duab xis yog ruaj khov, tus nqi corrosion yog zoo xoom; qhov twg nws tsis yog, kev tawm tsam tuaj yeem nrawm thiab sib xws.
Corrosion Behavior nyob rau hauv cov kua qaub
Tantalum yog resistant rau hydrochloric acid thiab nitric acid nyob rau hauv dav dav concentration thiab kub ntau yam, thiab nws withstands aqua regia ntawm ambient kub, uas ua rau nws ib tug natural xaiv rau kev kuaj thiab txheej txheem cov cuab yeej tuav sib xyaw ntxhia acids. Nws raug tawm tsam los ntawm hydrofluoric acid thiab los ntawm cov tshuaj fluoride- uas muaj cov khoom sib xyaw, vim tias fluoride complexes tantalum ion thiab dissolves oxide zaj duab xis. Sulfuric acid tus cwj pwm yog qhov kub thiab txias - tseem ceeb: hauv qab li ntawm 150℃concentrated sulfuric acid tsis tshua muaj txiaj ntsig, thiab siab dua qhov kub ntawm qhov corrosion nce siab nrog txhua qhov ntxiv ntawm qhov kub thiab txias.
Cov ntaub ntawv immersion qhia qhia txog qhov zoo ntawm qhov nkhaus. Nyob rau hauv concentrated sulfuric acid qhov poob yog negligible nyob rau hauv lub cheeb tsam ntawm 175℃thiab tseem me me ntawm 200 degree, ntsuas nyob rau hauv txhiab ntawm ib millimeter ib xyoo. Ntawm 250℃tus nqi yog qhov kev txiav txim siab dua, hauv thaj tsam ntawm 0.1 hli hauv ib xyoos, thiab ntawm 300℃nws nce mus txog li 1 hli ib xyoos lossis ntau dua, uas tshem tawm tantalum los ntawm kev xav txog kev ua haujlwm tas mus li. Fuming sulfuric acid, uas muaj cov sulfur trioxide yaj, tseem muaj kev txhoj puab heev thiab tawm tsam tantalum ntawm qhov kub thiab txias li 130 degree; nws yuav tsum raug kho raws li qhov tsis yog{10}} qhov chaw pabcuam rau cov hlau. Txoj cai siv tau rau cov neeg tsim qauv yog kho cov concentrated sulfuric acid saum toj no 150℃thiab oleum ntawm qhov kub thiab txias raws li qhov tsis tau.
| Nruab nrab | Hom tantalum cwj pwm |
|---|---|
| Hydrochloric acid, tag nrho cov li niaj zaus concentration | Resistant ntawm ambient thiab nruab nrab siab kub |
| Nitric acid, tag nrho cov li niaj zaus concentration | Resistant ntau qhov kub thiab txias |
| Aqua regia, ambient | Resistant; oxide zaj duab xis nyob ruaj khov |
| Sulfuric acid, concentrated, qis dua 150 degree | Resistant, negligible ntsuas poob |
| Sulfuric acid, concentrated, 250-300 degree | Progressive nres; kwv yees li 0.1 mm / y ntawm 250℃nce mus txog 1 mm / y ntawm 300 degree |
| Fuming sulfuric acid (oleum) | Kev tawm tsam hnyav txawm nyob ze 130 degree; tsis yog ib puag ncig kev pabcuam |
| Hydrofluoric acid thiab fluoride sib tov | Kev nrawm nrawm; tantalum yuav tsum tsis txhob siv |
| Kub concentrated caustic daws | Tawm tsam; tsis haum |
Alkalis, Halogen thiab Gaseous Ib puag ncig
Molten thiab kub concentrated alkalis tawm tsam tantalum, yog li nws tsis yog tus neeg sib tw rau caustic evaporators lossis alkali-hlau tuav ntawm qhov kub thiab txias. Qhuav halogens feem ntau xav tau kev saib xyuas: fluorine thiab hydrogen fluoride tua cov hlau tam sim ntawd, thaum chlorine thiab bromine tolerable ntawm qhov kub thiab txias tab sis ua nruj heev thaum kub nce. Hydrogen yog ib qho kev txhawj xeeb tshwj xeeb vim tias tantalum absorbs nws yooj yim tshaj li ntawm 300 degree, tsim nkig hydride; hydrogen embrittlement, es tsis yog corrosion, feem ntau yog hom tsis ua haujlwm tiag tiag hauv hydrogen-cov kabmob lossis cathodically tiv thaiv kev pabcuam. Oxygen thiab nitrogen yog absorbed ntawm qhov kub thiab txias thiab ua rau poob ntawm ductility, uas yog vim li cas tag nrho cov high -kub ua ntawm tantalum, nrog rau vuam thiab annealing, yog ua nyob rau hauv lub nqus tsev vacuum los yog high - purity inert gas.
Anodic Oxidation thiab Capacitor Connection
Loj hlob anodically, Ta₂O₅ zaj duab xis thickens ntawm kwv yees li 1.6-2.0 nm ib volt, nrog ib tug dielectric tas li nyob rau hauv lub cheeb tsam ntawm 25-30, muab ib tug heev capacitance ib chav tsev ntim nrog zoo heev stability thiab tsis tshua muaj to. Qhov no yog vim li cas tantalum capacitors yog compact thiab txhim khu kev qha, thiab yog vim li cas capacitor -qib hmoov, hlau thiab ntawv yog lub qhov hluav taws xob loj rau cov hlau. Hauv cov txheej txheem cov khoom siv tib zaj duab xis muab cov tshuaj tiv thaiv corrosion, tab sis tus tsim qauv yuav tsum nco ntsoov tias cov yeeb yaj kiab nyias nyias thiab cov khoom siv puas tsuaj, abrasive slurries, siab - cov dej ntws tawm lossis cov tshuaj ntxuav tsis raug tuaj yeem nyob hauv zos. Yog li ntawd, Tantalum feem ntau yog siv los ua ib lub liner lossis cladding ntawm cov hlau, los yog raws li cov phab ntsa nyias thiab cov khoom siv hluav taws xob sib pauv, tsis yog cov khoom siv.
Cov ntawv, Fabrication thiab tuav
Cov ntaub ntawv khoom lag luam feem ntau tau them los ntawm cov lus qhia tshwj xeeb xws li ASTM B365 rau sawb, ntawv thiab phaj, nrog cov qib tsis sib xws uas tau xaiv UNS R05200 thiab R05400 thiab ob tus qauv alloys yog Ta-2.5W (UNS R05252) thiab Ta-10W (UNS R05255). Cov tungsten alloys nce lub zog thiab muaj peev xwm kub ntawm qee tus nqi hauv kev tiv thaiv corrosion thiab formability; qib 2.5% yog ib qho kev sib haum xeeb, thaum 10% qib yog siv qhov twg txhua yam muaj zog ntawm qhov kub thiab txias yog qhov tseem ceeb. ASTM F560 npog unalloyed tantalum rau kev phais implants, qhov twg hlau lub biocompatibility thiab radiographic visibility muaj nuj nqis.
Tantalum yog fabricated los ntawm txias ua hauj lwm nrog nquag intermediate anneals; nws ua haujlwm- hardens tau yooj yim thiab yuav tsum tau khoov radii.
Vuam yog ua los ntawm tungsten inert gas los yog electron beam nyob rau hauv ib tug inert chamber nrog dew-point tswj; lub vuam thiab cua sov- thaj tsam cuam tshuam yuav tsum tsis txhob muaj xim, vim tias kev hloov xim qhia tias cov pa oxygen los yog nitrogen tuaj yeem tuaj txog
Machining generates ductile, stringy chips thiab cov cuab yeej siab loads; cov cuab yeej ntse, kev teeb tsa nruj thiab ua kom txias txias yog qhov tseem ceeb, thiab tib yam kev tiv thaiv hluav taws siv rau lwm cov hlau reactive refractory nrog cov chips zoo.
Kev tu yuav tsum zam kom tsis txhob muaj cov tshuaj hydrofluoric acid thiab fluoride- muaj cov tshuaj txhuam hniav hauv txhua theem, suav nrog kev hnav khaub ncaws thiab vuam.
Common Misconceptions
"Tantalum tiv thaiv txhua yam acids."Nws tsis yog; fluoride media, oleum, kub concentrated sulfuric acid thiab kub caustic daws txhua yam tawm tsam nws.
"Hydrogen tsis muaj teeb meem rau tantalum."Hydrogen absorption saum toj li 300℃ua nkig hydride, thiab cathodic tiv thaiv tuaj yeem tsav cov tshuaj tiv thaiv tib yam.
"Tantalum tuaj yeem siv los ua cov hlau zoo tib yam."Nws cov nqi thiab qhov ntom ntom ua rau nws ua rau hauv ob sab phlu, cladding lossis nyias - cov khoom siv phab ntsa, tsis yog qhov kev xaiv ntau yam.
"Txhua yam tshuaj ntxuav tau siv tau."Cov tshuaj fluoride-cov tshuaj ntxuav tes thiab cov da dej da dej ua kom cov yeeb yaj kiab tiv thaiv tsis pub dhau feeb.
FAQ
Q: Puas yog tantalum tiv thaiv aqua regia?
Yog, ntawm qhov kub thiab txias nws yog resistant, uas yog ib qho ntawm cov khoom uas txawv nws ntawm feem ntau stainless hlau thiab npib tsib xee alloys.
Q: Dab tsi yog qhov ntsuas kub rau tantalum hauv concentrated sulfuric acid?
Hauv qab li 150℃qhov kev tawm tsam yog negligible; ntawm 250℃tus nqi yog kwv yees li 0.1 hli hauv ib xyoos thiab ntawm 300℃txog 1 hli hauv ib xyoos, yog li kev pabcuam txuas ntxiv siab tshaj 150℃yuav tsum tau ua tib zoo soj ntsuam.
Q: Vim li cas fluoride thiaj ua rau tantalum puas?
Fluoride ions complex tantalum muaj zog thiab yaj cov tshuaj tiv thaiv oxide zaj duab xis, yog li kev tawm tsam sai heev txawm nyob rau ntawm qhov kub thiab txias.
Q: Dab tsi yog Ta-2.5W thiab Ta-10W siv rau?
Cov tungsten alloys txhawb zog thiab siab -kub muaj peev xwm; Ta-2.5W yog ib qho kev sib haum xeeb rau cov txheej txheem cov cuab yeej, thiab Ta-10W yog siv qhov twg txhua yam muaj zog ntawm qhov kub thiab txias.
Q: Dab tsi yog qhov kev tiv thaiv oxide ntawm tantalum?
Ta₂O₅, ib coherent dielectric zaj duab xis uas tsim spontaneously nyob rau hauv cov huab cua thiab yuav zus tau tej anodically mus rau ib tug tswj thickness ntawm txog 1.6-2.0 nm ib volt.
Q: tantalum puas tuaj yeem welded hauv huab cua?
Tsis yog. Nws yuav tsum tau welded nyob rau hauv lub nqus tsev vacuum los yog siab - purity inert gas nrog nruj heev noo noo tswj, vim hais tias oxygen, nitrogen thiab hydrogen absorption embrittles sib koom ua ke.
