Atomic naj npawb	41
CAS nr	7440-03-1 : kuv
Atomic loj	92.91 ib
Melting point	2468 ° C
Boiling point	4900 ° C
Atomic ntim	0, 0180 nm3
Qhov ceev ntawm 20 ° C	8.55 g / cm³
Crystal qauv	lub cev-center cubic
Lattice tas li	0.3294 [nm]
Kev nplua nuj nyob rau hauv lub ntiaj teb crust	20.0 [g/t]
Ceev lub suab	3480 m / s (ntawm rt) (nyias pas nrig)
Thermal expansion	7.3 µm / (m·K) (ntawm 25 ° C)
Thermal conductivity	53.7W / (m·K)
Hluav taws xob resistivity	152 nΩ·m (ntawm 20 ° C)
Mohs hardness	6.0
Vickers hardness	870-1320 Mpa
Brinell hardness	1735-2450 Mpa

Niobium, yav tas los hu ua columbium, yog cov khoom siv tshuaj nrog cov cim Nb (yav tas los Cb) thiab atomic tooj 41. Nws yog mos, grey, crystalline, ductile hloov hlau, feem ntau pom nyob rau hauv cov minerals pyrochlore thiab columbite, li no lub npe qub " columbium". Nws lub npe los ntawm Greek mythology, tshwj xeeb tshaj yog Niobe, uas yog tus ntxhais ntawm Tantalus, lub npe ntawm tantalum. Lub npe qhia txog qhov zoo sib xws ntawm ob lub ntsiab lus hauv lawv lub cev thiab tshuaj lom neeg, ua rau lawv nyuaj rau qhov txawv.

Tus kws tshuaj Askiv Askiv Charles Hatchett tau tshaj tawm cov ntsiab lus tshiab zoo ib yam li tantalum hauv xyoo 1801 thiab muab nws lub npe hu ua columbium. Nyob rau xyoo 1809, tus kws tshuaj Askiv Askiv William Hyde Wollaston tsis raug txiav txim siab tias tantalum thiab columbium zoo ib yam. Tus kws tshuaj German Heinrich Rose tau txiav txim siab xyoo 1846 tias tantalum ores muaj cov khoom thib ob, uas nws hu ua niobium. Xyoo 1864 thiab 1865, cov kev tshawb fawb tshawb fawb tau qhia meej tias niobium thiab columbium yog tib lub ntsiab (raws li qhov txawv ntawm tantalum), thiab rau ib puas xyoo ob lub npe tau siv sib hloov. Niobium tau raug lees paub los ua lub npe ntawm cov khoom hauv xyoo 1949, tab sis lub npe columbium tseem siv tam sim no hauv metallurgy hauv Tebchaws Meskas.

Nws tsis yog txog thaum xyoo pua 20th uas niobium tau siv thawj zaug hauv kev lag luam. Brazil yog tus tsim khoom ntawm niobium thiab ferroniobium, ib qho alloy ntawm 60-70% niobium nrog hlau. Niobium feem ntau yog siv rau hauv cov hlau, qhov loj tshaj plaws hauv cov hlau tshwj xeeb xws li siv hauv cov kav dej. Txawm hais tias cov hlau no muaj qhov siab tshaj plaws ntawm 0.1%, qhov feem pua ​​​​me me ntawm niobium txhim kho lub zog ntawm cov hlau. Qhov kub thiab txias ntawm niobium-muaj superalloys yog qhov tseem ceeb rau nws siv hauv dav hlau thiab foob pob hluav taws cav.

Niobium yog siv nyob rau hauv ntau yam khoom siv superconducting. Cov superconducting alloys, kuj muaj titanium thiab tin, yog siv dav hauv cov hlau nplaum superconducting ntawm MRI scanners. Lwm daim ntawv thov ntawm niobium suav nrog vuam, kev lag luam nuclear, hluav taws xob, optics, numismatics, thiab hniav nyiaj hniav kub. Hauv ob daim ntawv thov kawg, qhov tsis tshua muaj tshuaj lom thiab iridescence tsim los ntawm anodization yog cov khoom xav tau. Niobium yog suav tias yog ib qho tseem ceeb ntawm kev siv thev naus laus zis.

Cov yam ntxwv ntawm lub cev

Niobium yog ib tug lustrous, grey, ductile, paramagnetic hlau nyob rau hauv pab pawg neeg 5 ntawm lub periodic rooj (saib lub rooj), nrog ib tug electron configuration nyob rau hauv lub sab nrauv shells atypical rau pawg 5. (Qhov no yuav pom nyob rau hauv lub zej zog ntawm ruthenium (44), rhodium (45), thiab palladium (46).

Txawm hais tias nws tau xav tias muaj lub cev-qhov nruab nrab ntawm lub pob zeb siv lead ua los ntawm qhov xoom mus rau nws qhov melting point, qhov kev ntsuas siab ntawm thermal expansion raws peb lub crystallographic axes qhia anisotropies uas tsis sib haum nrog cov qauv cubic.[28] Yog li ntawd, kev tshawb fawb ntxiv thiab tshawb pom hauv cheeb tsam no xav tau.

Niobium dhau los ua superconductor ntawm qhov kub thiab txias. Ntawm atmospheric siab, nws muaj qhov tseem ceeb tshaj plaws kub ntawm lub elemental superconductors ntawm 9.2 K. Niobium muaj qhov zoo tshaj plaws sib nqus nkag qhov tob ntawm txhua lub caij. Tsis tas li ntawd, nws yog ib qho ntawm peb hom II superconductors, nrog rau vanadium thiab technetium. Lub superconductive zog muaj zog nyob ntawm purity ntawm niobium hlau.

Thaum ntshiab heev, nws yog comparatively mos thiab ductile, tab sis impurities ua rau nws nyuaj.

Cov hlau muaj qhov tsis tshua muaj kev ntes cov hlaws rau thermal neutrons; yog li nws yog siv rau hauv kev lag luam nuclear qhov twg neutron pob tshab qauv xav tau.

Cov yam ntxwv tshuaj

Cov hlau yuav siv lub ntsej muag xiav thaum raug huab cua ntawm chav tsev kub rau lub sijhawm ntev. Txawm hais tias muaj cov ntsiab lus siab melting nyob rau hauv daim ntawv (2,468 ° C), nws muaj qhov ntom ntom dua li lwm cov hlau refractory. Tsis tas li ntawd, nws yog corrosion-resistant, nthuav tawm superconductivity zog, thiab cov ntaub ntawv dielectric oxide txheej.

Niobium yog me ntsis electropositive thiab ntau compact dua li nws ua ntej nyob rau hauv lub periodic rooj, zirconium, whereas nws yog zoo tib yam nyob rau hauv loj rau lub hnyav tantalum atoms, vim hais tias ntawm lub lanthanide contraction. Yog li ntawd, niobium cov tshuaj muaj zog zoo ib yam li cov tantalum, uas tshwm ncaj qha hauv qab niobium nyob rau hauv lub sij hawm. Txawm hais tias nws qhov kev tiv thaiv corrosion tsis zoo li ntawm tantalum, tus nqi qis dua thiab muaj ntau dua ua rau niobium txaus nyiam rau cov ntawv thov tsawg dua, xws li vat linings hauv cov nroj tsuag tshuaj.