Boron nitride (BN) yog cov tshuaj sib xyaw ua ke ntawm boron thiab nitrogen atoms. Nws muaj nyob rau hauv ntau hom qauv, txhua tus muaj nws tus kheej cov khoom tshwj xeeb. Ib qho ntawm cov yam ntxwv tseem ceeb tshaj plaws ntawm boron nitride yog nws cov ntsiab lus melting siab, uas ua rau nws muaj txiaj ntsig zoo hauv ntau daim ntawv thov kev lag luam.
Lub melting point ntawm boron nitride nyob ntawm daim ntawv tshwj xeeb polymorphic. Hexagonal boron nitride, feem ntau hu ua dawb graphite vim nws cov txheej txheem zoo sib xws, muaj qhov taw tes yaj ntawm ib ncig ntawm 3000 degrees Celsius (5432 degrees Fahrenheit). Vim tias muaj zog covalent bonds ntawm boron thiab nitrogen atoms nyob rau hauv lub hexagonal lattice qauv, cov hlau no muaj ib tug heev melting point.
Hexagonal boron nitride paub txog nws cov thermal stability zoo heev, ua rau nws yog ib qho tseem ceeb ntawm cov ntawv thov kub xws li crucibles thiab insulating cov ntaub ntawv. Nws cov thermal conductivity kuj zoo kawg li, thiab nws feem ntau yog siv los ua cov khoom siv hluav taws xob hauv cov khoom siv hluav taws xob.
Cubic boron nitride, ntawm qhov tod tes, muaj qhov melting point ntau dua, tshaj 3900 degrees Celsius (7052 degrees Fahrenheit). Daim ntawv no ntawm boron nitride yog analogous rau pob zeb diamond nyob rau hauv cov nqe lus ntawm nws cov qauv siv lead ua thiab hardness. Qhov tseeb, cubic boron nitride feem ntau hu ua "dawb pob zeb diamond" vim nws hardness thiab tsos. Qhov tshwj xeeb hardness no, ua ke nrog lub siab melting point, ua rau c-BN haum rau cov cuab yeej txiav, sib tsoo lub log, thiab lwm yam kev siv abrasive, tshwj xeeb tshaj yog thaum cuam tshuam nrog cov khoom uas nyuaj rau tshuab siv cov txheej txheem ib txwm muaj.
Qhov zoo kawg nkaus melting ntsiab lus ntawm boron nitride variants pab txhawb rau lawv versatility nyob rau hauv huab cua kub ib puag ncig. Tsis tas li ntawd, boron nitride cov tshuaj inertness thiab tsis kam mus rau oxidation ntxiv txhim khu nws tsim nyog rau kev siv nyob rau hauv high-kub daim ntaub ntawv. Cov khoom siv tsis nkag siab nrog cov tshuaj lom neeg feem ntau, ua kom nws ruaj khov thiab siv tau ntev hauv ntau qhov chaw lag luam.
Nyob rau hauv xaus, boron nitride lub siab melting point yog ib tug txhais cov yam ntxwv uas underlies nws pab tau nyob rau hauv ntau yam kev siv. Boron nitride yog thermally ruaj khov, tshwj xeeb tshaj yog nyob rau hauv nws cov hexagonal thiab cubic forms. Qhov no ua rau nws yog ib qho khoom muaj txiaj ntsig hauv thaj chaw uas muaj qhov kub thiab txias thiab cov xwm txheej nyuaj. Nws tuaj yeem siv los ua cov thermal insulator thiab yog ib feem tseem ceeb ntawm cov cuab yeej siv niaj hnub no.
