Cov yam ntxwv ntawm tungsten hlau

Nyob rau hauv daim ntawv ntawm cov hlau, tungsten tuav ntau yam ntawm nws cov khoom muaj txiaj ntsig, nrog rau nws qhov siab melting point, qis coefficient ntawm thermal expansion, thiab tsis tshua muaj vapor siab ntawm qhov kub siab. Vim hais tias tungsten hlau kuj qhia tau zoo hluav taws xob thiab thermal conductivity, nws yog siv dav rau cov khoom siv hluav taws xob, thiab cov thermocouples.
Hlau diameters feem ntau qhia nyob rau hauv millimeters los yog mils (phav txhiab ntawm ib nti). Txawm li cas los xij, tungsten hlau txoj kab uas hla feem ntau yog qhia hauv milligrams - 14.7 mg, 3.05 mg, 246.7 mg thiab hais txog. Qhov kev xyaum no yog hnub rov qab mus rau hnub thaum, tsis muaj cov cuab yeej los ntsuas qhov tseeb ntawm cov xov hlau nyias nyias (.001 "mus txog .020" inch), lub rooj sib tham yog ntsuas qhov hnyav ntawm 200 mm (txog 8 ") ntawm tungsten hlau thiab suav txoj kab uas hla (D) ntawm tungsten hlau raws li qhov hnyav ntawm ib chav tsev ntev, siv cov qauv lej hauv qab no:

D = 0.71746 x square root (mg qhov hnyav / 200 mm ntev)”

Tus qauv txoj kab uas hla kam rau ua 1s 士3% ntawm qhov ntsuas qhov hnyav, txawm hais tias muaj kev tiv thaiv nruj dua, nyob ntawm daim ntawv thov rau cov khoom siv hlau. Qhov no txoj kev ntawm kev nthuav qhia txoj kab uas hla kuj xav hais tias cov hlau muaj ib tug tas mus li txoj kab uas hla, tsis muaj qhov tseem ceeb va 「1ation, necking down, los yog lwm yam conical teebmeem nyob qhov twg ntawm txoj kab uas hla.
Rau cov xov hlau tuab (.020 "mus rau .250" txoj kab uas hla), siv cov millmeter lossis mil ntsuas; cov tolerances yog qhia raws li ib feem ntawm txoj kab uas hla, nrog rau tus qauv kam rau ua ntawm 1.5%
Feem ntau cov tungsten hlau yog doped nrog cov lej ntawm cov poov tshuaj tsim ib qho elongated, interlocking grain qauv uas exh 心ts tsis-sag zog tom qab recrystallization. Qhov kev coj ua no yog hnub rov qab mus rau tungsten hlau qhov tseem ceeb siv hauv cov qhov muag teeb pom kev zoo, thaum qhov kub dawb-kub yuav ua rau filament sag thiab teeb tsis ua haujlwm. Qhov sib ntxiv ntawm dopants alumina, silica, thiab poov tshuaj nyob rau hauv cov hmoov sib tov theem yuav hloov cov khoom ntawm tungsten hlau. Nyob rau hauv tus txheej txheem ntawm kub swaging thiab kub kos lub tungsten hlau, lub alumina thiab silica tawm-gas thiab cov poov tshuaj nyob, muab cov hlau nws tsis-sag zog thiab enabling incandescent qhov muag teev ua hauj lwm yam tsis muaj arcing thiab filament tsis ua hauj lwm.
Txawm hais tias kev siv tungsten hlau niaj hnub no tau nthuav dav dhau ntawm filaments rau cov teeb ci, kev siv dopants hauv tungsten hlau tsim txuas ntxiv. Ua kom muaj qhov kub ntawm recrystallization ntau dua li thaum nyob rau hauv nws lub xeev ntshiab, doped tungsten (nrog rau molybdenum hlau) tuaj yeem nyob twj ywm ntawm chav tsev kub thiab kub ua haujlwm siab heev. Lub resulting elongated, stacked qauv kuj muab cov doped hlau zog xws li zoo creep kuj dimensional stability, thiab me ntsis machining yooj yim dua cov khoom ntshiab (undoped).

Doped tungsten hlau feem ntau yog tsim nyob rau hauv qhov ntau thiab tsawg los ntawm 0.001 "mus txog 0.025" inch thiab tseem siv tau rau cov teeb pom kev zoo thiab xaim filament daim ntaub ntawv, nrog rau ua tau zoo nyob rau hauv qhov cub, deposition, thiab high-temperature daim ntaub ntawv. Tsis tas li ntawd, qee lub tuam txhab (xws li Metal Cutting Corporation) muab cov ntshiab, tsis muaj tungsten hlau rau cov ntawv thov uas purity yog qhov tseem ceeb. Lub sij hawm no, lub purest tungsten hlau muaj yog 99.99% ntshiab, ua los ntawm 99.999% ntshiab hmoov.

Tsis zoo li cov khoom siv hlau ferrous hlau - uas tuaj yeem raug txiav txim 1n sib txawv annealed xeev, los ntawm tag nrho cov nyuaj mus rau ntau yam ntawm softer zaum kawg tej yam kev mob - tungsten hlau raws li ib tug ntshiab lub caij (thiab ib sab ntawm ib tug txwv xaiv ntawm alloys) yeej tsis muaj xws li ib tug ntau yam ntawm khoom. Txawm li cas los xij, vim tias cov txheej txheem thiab cov cuab yeej sib txawv, cov khoom siv ntawm tungsten yuav tsum sib txawv ntawm cov tuam txhab, vim tias tsis muaj ob lub tuam txhab siv tib lub xov tooj loj, cov khoom siv swaging tshwj xeeb, thiab cov sij hawm kos duab thiab annealing. Yog li ntawd, nws yuav yog qhov muaj hmoo zoo sib xws yog tias tungsten ua los ntawm cov tuam txhab sib txawv muaj cov khoom siv kho tshuab zoo ib yam. Qhov tseeb, lawv tuaj yeem sib txawv li ntawm 10%. Tab sis kom nug ib lub chaw tsim khoom tungsten kom sib txawv nws tus kheej tensile qhov tseem ceeb los ntawm 50% yog tsis yooj yim sua.