Tungsten - dab tsi yog qhov no? Lub degree ntawm oxidation ntawm lub tungsten. Cov cheeb tsam ntawm daim ntawv thov ntawm tungsten

Tungsten - tshuaj caij uas nws atomic tus xov tooj yog sib npaug zos rau 74. Qhov no hnyav hlau los ntawm, nyob rau siab zog steel-grey mus dawb, uas ua rau nws yooj yim nyob rau hauv ntau indispensable. Melting taw tes nws yog siab tshaj uas ntawm lwm yam hlau, thiab yog li ntawd nws yog siv raws li filaments nyob rau hauv lub filament teeb thiab cua sov ntsiab nyob rau hauv hluav taws xob furnaces (e.g., zirconium-tungsten hlau). Science News for KIDS caij tso cai nws siv raws li ib tug catalyst. Huab hardness ua rau nws haum rau siv nyob rau hauv "HSS", uas tso cai rau txiav ntaub ntawv nrog ib tug ntau dua kev ceev tshaj cov hlau, thiab superalloys. Tungsten carbide caij mus cov pa roj carbon compound yog ib lub yam tshuaj lub npe hu thiab siv tau rau zus tau tej cov milling thiab xa cov cuab yeej. Tungstates ntawm calcium thiab magnesium yog lug siv nyob rau hauv fluorescent teeb, thiab tungsten oxides - mus rau hauv inks thiab tej hub glazes.

Keeb kwm ntawm foundations

Cov assumption ntawm cov hav zoov no lub caij twb xub pom tias nyob rau hauv 1779 los ntawm Peter hma, thaum nws tshawb mineral wolframite thiab xaus lus hais tias nws yuav tsum muaj ib tug tshiab substance. Nyob rau hauv 1781 Carl Wilhelm Scheele los nrog nkawd tham hais tias ib tug tshiab acid yuav tsum tau los ntawm tungstenita. Thorburn Scheele thiab Bergman tswv yim mus rau xav tau tshiab hlau los ntawm yuav txo tau ntawm lub acid, hu ua tungstenovoy. Nyob rau hauv 1783, ob tug kwv tij, Jose thiab Fausto Elguyar pom nyob rau hauv tungsten acid, uas yog zoo tib yam rau tungstenovoy. Nyob rau hauv tib lub xyoo cov kwv tij tau zoo nyob rau hauv cais tungsten los ntawm nws, siv charcoal.

Thaum lub sij hawm ob ntiaj teb rog, qhov no tshuaj caij tau ua si ib tug lossis loj lub luag hauj lwm. hlau kuj rau siab kub, thiab huab toughness tungsten alloys ua ib qho tseem ceeb raw khoom rau cov tub rog kev lag luam. Warring ob tog tso siab rau Portugal raws li lub ntsiab qhov chaw ntawm wolframite nyob rau hauv teb chaws Europe.

Ua nyob rau hauv cov xwm

Lub caij no tshwm sim nyob rau hauv cov xwm wolframite (FeWO ₄ / MnWO _4), scheelite (CaWO _4), thiab Ferber Gyubnera. Tseem ceeb deposits ntawm cov zaub mov muaj nyob rau hauv lub tebchaws United States nyob rau hauv California thiab Colorado, Bolivia, Tuam Tshoj, South Kauslim, Russia thiab Portugal. Tuam Tshoj tuas txog 75% ntawm lub ntiaj teb no zus tau tej cov tungsten. Hlau yog tau los ntawm kev txo ib tug oxide nrog hydrogen los yog cov pa roj carbon.

Ntiaj teb reserves yog kwv yees li ntawm 7 plhom tons yuav tsum hais tias 30% ntawm lawv -. Wolframite deposits thiab 70% - scheelite. Thaum lub sij hawm no, lawv txoj kev loj hlob yog tsis kev lag kev luam zoo. Nyob tam sim no noj ntau cov reserves yuav kav xwb 140 xyoo. Lwm nqi qhov chaw ntawm tungsten yog seem hlau.

Ntsiab nta

Tungsten - caij, uas yog dej num raws li ib txoj kev hloov hlau. Nws cim W yog muab tau los ntawm Latin lo lus wolframium. Nyob rau hauv lub periodic table, nws yog nyob rau hauv lub VI pab pawg neeg ntawm tantalum thiab rhenium.

Ntshiab tungsten - ib tug khoom khoom, uas nws cev nqaij daim tawv mas nws txawv ntawm steel-grey mus dawb tin. Nrog kov ntawm hlau yuav nkig thiab yooj yim mus ua hauj lwm nrog nws, tab sis yog hais tias lawv ua tsis yog, nws muaj peev xwm yuav txiav nrog ib tug hacksaw. Nyob rau hauv tas li ntawd, nws yuav forged, kuav los tiag thiab twv tawm.

Tungsten - tshuaj caij, lub melting point ntawm uas yog lub siab tshaj plaws ntawm tag nrho cov hlau (3422 ° C). Tsis tas li ntawd nws muaj tus nqi qis tshaj vapor siab. Tensile zog ntawm T> 1650 ° C nws tseem yog cov coob. Lub caij no mas resistant rau corrosion thiab yog tsuas yog me ntsis raug mineral acids. Thaum kev sib cuag nrog cov huab cua nyob rau hauv lub hlau nto ib tug tiv oxide txheej yog tsim, tab sis kiag li oxidized tungsten thaum muaj kev kub kub. Thaum ntxiv nyob rau hauv me me mus rau lub steel nws hardness tsub kom sharply.

isotopes

Nyob rau hauv cov xwm tungsten muaj tsib radioisotopes, tab sis lawv muaj xws li ib tug ntev ib nrab-lub neej, hais tias lawv yuav muab suav hais tias ruaj khov. Tag nrho cov ntawm lawv lub caij nplooj zeeg nyob rau hauv lub hafnium-72 nrog rau cov emission ntawm alpha hais (Helium nuclei coj-4). Alpha lwj yog cai nyob rau hauv tsuas ¹⁸⁰ W, qhov uas yooj yim thiab feem ntau tsawg ntawm cov isotopes. Nyob rau nruab nrab, 1 g ntawm tej yam ntuj tso tungsten ib xyoo tshwm sim ob alpha lwj ntawm ¹⁸⁰ W.

Tsis tas li ntawd, 27 piav tungsten dag tej isotopes. Qhov tseem ruaj khov ntawm lawv yog ¹⁸¹ W nrog ib tug ib nrab neej ntawm 121,2 hnub, ¹⁸⁵ W (75,1 hnub), ¹⁸⁸ W (69,4 hnub) thiab ¹⁷⁸ W (21,6 hnub). Tag nrho lwm cov dag isotopes ntawm ib nrab-lub neej yog tsis ntau tshaj li ib hnub, thiab feem ntau ntawm lawv - yam tsawg kawg 8 feeb. Tungsten kuj muaj plaub "metastable" xeev, feem ntau ruaj khov - ^179m W (6,4 min).

kev sib txuas

Cov tshuaj sib txuas ntawm tungsten oxidation tooj hloov los ntawm 2 mus rau 6, ntawm uas feem ntau yog rau. Lub caij feem ntau los mus rau hauv kev sib cuag nrog cov pa, txoj kev daj trioxide (WO _3), uas yog soluble nyob rau hauv aqueous alkaline daws teeb meem nyob rau hauv daim ntawv ntawm ions, tungstate (WO ₄ ^2-).

daim ntawv thov

Txij li thaum tungsten muaj ib tug heev melting kub thiab zas (yuav tsum kos rau hauv hlau), nws yog dav siv raws li ib tug filament qhov muag thiab lub tshuab nqus tsev hlab li zoo raws li nyob rau hauv lub cua sov ntsiab ntawm hluav taws xob furnaces. Nyob rau hauv tas li ntawd, cov ntaub ntawv uas yuav mas huab tej yam kev mob. Ib qho ntawm nws lub npe hu daim ntaub ntawv - arc vuam nrog tungsten electrode nyob rau hauv kev tiv thaiv cov roj.

Tsis tshua muaj neeg nyuaj tungsten - zoo tagnrho tivthaiv hnyav riam phom alloys. Cov kev kub ceev yog siv nyob rau hauv lub weighing teeb meem, counterweights thiab ballast keels rau yachts, raws li zoo raws li xib xub hluav taws (80-97%). High ceev steel, uas tej zaum yuav txiav cov khoom nyob rau ntau dua speeds tshaj carbon, muaj txog li 18% ntawm cov tshuaj yeeb dej caw. Lub turbine hniav, hnav-resistant qhov chaw thiab coatings siv "superalloys" muaj tungsten. Qhov no tshav kub-resistant qhwv alloys uas khiav lag luam ntawm txhawb kub.

Thermal expansion ntawm lub tshuaj lub caij zoo li borosilicate iav, li ntawd nws yog siv rau qhov siv thiab ua cov iav-rau-hlau foob. Composites muaj tungsten - ib tug zoo hloov rau cov hlau lead hauv cov mos txwv thiab tua. Nyob rau hauv alloys ntawm npib tsib xee, hlau los yog cobalt, nws yog los zoo li percussion. Zoo li ib tug mos txwv mus ntaus ib lub hom phiaj siv nws kinetic zog. Nyob rau hauv kev circuits ntawm lub tungsten compound yuav ua rau transistors. Ib txhia hom ntawm cov hlua rau seev suab paj nruas ua los ntawm tungsten hlau.

Kev siv cov tebchaw

Lub exceptional hardness ntawm tungsten carbide (W ₂ C, WC) ua rau nws lub feem ntau cov ntaub ntawv uas rau milling thiab xa cov cuab yeej. Nws yog siv nyob rau hauv metallurgy, tsuas, roj av thiab kev tsim kho industries. Tungsten carbide kuj yog siv nyob rau hauv kev tsim hniav nyiaj hniav kub vim nws yog hypoallergenic thiab tsis zoo li mus poob lawv ci.

Los ntawm nws oxides ua lub icing. Tungsten "bronze" (thiaj li hu ua vim hais tias ntawm cov xim oxides) yog siv nyob rau hauv cov xim tsev. tungstates ntawm calcium thiab magnesium siv nyob rau hauv fluorescent teeb. Tungstate siv lead ua scintillation ntes yog siv nyob rau hauv nuclear tshuaj thiab physics. Cov ntsev yog siv nyob rau hauv lub tshuaj kev lag luam thiab tawv kev lag luam. Tungsten disulfide yog ib tug siab kub roj nplua nyeem, mas 500 ° C. Ib txhia ntawm cov tebchaw uas muaj tungsten, yog siv raws li catalysts nyob rau hauv Science News for KIDS.

zog

Cov yooj yim lub cev thaj chaw ntawm W raws li nram no:

• Lub atomic tooj ntawm 74.
• Atomic yuag: 183,85.
• Melting point: 3410 ° C.
• Boiling point: 5660 ° C.
• Nyhav: 19,3 g / cm ³ nyob rau hauv 20 ° C.
• oxidation lub xeev ntawm +2, +3, +4, +5, + 6.
• Hauv configuration: [Xe] 4 d f ^{May 14 Lub rau hli ntuj 4} s ^2.