Boron Carbide (B4C) yog cov khoom siv hluav taws xob ruaj khov uas muaj Boron thiab carbon. Boron Carbide yog ib yam khoom nyuaj tshaj plaws paub, qeb thib peb tom qab cubic Boron nitride thiab pob zeb diamond. Nws yog cov khoom siv sib xyaw ua ke siv ntau yam kev siv tseem ceeb, suav nrog lub tank armor, mos txwv vests, thiab cav sabotage hmoov. Qhov tseeb, nws yog cov khoom siv rau ntau yam kev siv hauv kev lag luam. Kab lus no muab cov ntsiab lus ntawm Boron Carbide thiab nws qhov zoo.
Boron Carbide yog dab tsi?
Boron Carbide yog cov tshuaj lom neeg tseem ceeb nrog cov qauv siv lead ua zoo li icosahedral-based borides. Lub compound tau pom nyob rau hauv lub xyoo pua puv 19 raws li ib tug byproduct ntawm hlau boride tshua. Nws tsis tau paub tias muaj cov tshuaj formula kom txog thaum xyoo 1930, thaum nws cov tshuaj muaj pes tsawg leeg tau kwv yees tias yog B4C. X-ray crystallography ntawm cov khoom qhia tau hais tias nws muaj cov qauv nyuaj heev ua los ntawm ob qho tib si C-B-C chains thiab B12 icosahedra.
Boron Carbide muaj qhov tawv tawv heev (9.5-9.75 ntawm Mohs nplai), ruaj khov tiv thaiv ionizing hluav taws xob, tiv thaiv cov tshuaj tiv thaiv, thiab cov khoom tiv thaiv neutron zoo heev. Vickers hardness, elastic modulus, thiab tawg toughness ntawm Boron Carbide yuav luag tib yam li cov pob zeb diamond.
Vim nws qhov hnyav hnyav, Boron Carbide kuj tseem hu ua "dub pob zeb diamond." Nws kuj tau pom tias muaj cov khoom siv semiconducting, nrog hopping-type thauj dominating nws cov khoom hluav taws xob. Nws yog p-hom semiconductor. Vim nws qhov hardness heev, nws yog suav hais tias yog ib tug hnav-resistant technical ceramic khoom, ua rau nws haum rau kev ua lwm yam tsis tshua muaj zog tshuaj. Ntxiv nrog rau nws cov khoom siv kho tshuab zoo thiab tsis tshua muaj lub ntiajteb txawj nqus, nws yog qhov zoo tagnrho rau kev ua cov ris tsho hnav.
Kev tsim khoom ntawm Boron Carbide Ceramics
Boron Carbide hmoov yog ua lag luam los ntawm kev sib xyaw ua ke (uas suav nrog txo Boron anhydride (B2O3) nrog cov pa roj carbon) lossis cov tshuaj tiv thaiv magnesiothermic (uas yuav ua rau Boron anhydride hnov mob nrog magnesium nyob rau hauv muaj cov pa roj carbon dub). Nyob rau hauv thawj cov tshuaj tiv thaiv, cov khoom tsim ib tug loj qe-zoo li tus pob nyob rau hauv nruab nrab ntawm lub smelter. Cov khoom siv qe zoo li no tau muab rho tawm, crushed, thiab ces milled mus rau qhov tsim nyog grain loj rau kev siv zaum kawg.
Nyob rau hauv cov ntaub ntawv ntawm cov tshuaj tiv thaiv magnesiothermic, stoichiometric Carbide nrog qis granularity tau txais ncaj qha, tab sis nws muaj impurities, suav nrog txog li 2% graphite. Vim tias nws yog ib qho kev sib koom ua ke ntawm cov khoom siv tsis zoo, Boron Carbide yog qhov nyuaj rau sinter yam tsis siv cua sov thiab siab ib txhij. Vim li no, Boron Carbide feem ntau ua rau cov duab ntom ntom los ntawm kub nias zoo, cov hmoov ntshiab (2 m) ntawm qhov kub siab (2100-2200 ° C) hauv lub tshuab nqus tsev lossis inert cua.
Lwm txoj hauv kev los ua Boron Carbide yog qhov tsis muaj zog sintering ntawm qhov kub thiab txias (2300-2400 ° C), uas nyob ze rau qhov melting point ntawm Boron Carbide. Txhawm rau pab txo qhov kub thiab txias uas yuav tsum tau ua kom ntom ntom thaum lub sijhawm txheej txheem no, sintering pab xws li alumina, Cr, Co, Ni, thiab iav ntxiv rau cov hmoov sib tov.
Kev siv ntawm Boron Carbide Ceramics
Boron Carbide muaj ntau yam kev siv sib txawv.
Boron Carbide yog siv los ua tus neeg sawv cev thiab cov khoom abrasive.
Boron Carbide nyob rau hauv daim ntawv hmoov yog haum rau siv raws li ib tug abrasive thiab lapping tus neeg sawv cev nrog ib tug siab npaum li cas ntawm cov khoom tshem tawm thaum ua cov ntaub ntawv ultra-hard.
Boron Carbide yog siv los tsim cov ceramic blasting nozzles.
Boron Carbide yog qhov hnav tsis taus, ua rau nws yog ib qho khoom siv zoo heev rau blasting nozzles thaum sintered. Txawm tias siv nrog cov tawv tawv abrasive blasting cov neeg ua haujlwmxws li corundum thiab silicon Carbide, lub zog blasting tseem zoo ib yam, muaj tsawg tsawg, thiab cov nozzles muaj zog dua.
Boron Carbide yog siv los ua cov khoom tiv thaiv ballistic.
Boron Carbide muab kev tiv thaiv zoo sib xws rau cov hlau armored thiab aluminium oxide tab sis ntawm qhov hnyav dua. Cov cuab yeej siv tub rog niaj hnub no muaj cov yam ntxwv siab ntawm hardness, compressive zog, thiab siab modulus elasticity, ntxiv rau qhov hnyav. Boron Carbide yog qhov zoo tshaj rau txhua lwm yam khoom siv rau daim ntawv thov no.
Boron Carbide yog siv los ua neutron absorber.
Hauv engineering, qhov tseem ceeb tshaj plaws neutron absorber yog B10, siv los ua Boron Carbide hauv kev tswj lub tshuab hluav taws xob nuclear.
Lub atomic qauv ntawm boron ua rau nws ua tau zoo neutron absorber. Tshwj xeeb, 10B isotope, tam sim no nyob ib ncig ntawm 20% ntawm nws qhov kev nplua nuj nyob hauv ntuj, muaj qhov sib txawv ntawm cov hluav taws xob siab thiab tuaj yeem ntes cov thermal neutrons uas yog tsim los ntawm cov tshuaj tiv thaiv fission ntawm uranium.
Nuclear Qib Boron Carbide Disc Rau Neutron Absorption
