Boron Nitride: H-BN thiab C-BN

Boron nitride, (tshuaj formula BN), synthetically tsim crystalline compound ntawm boron thiab nitrogen, ib qho kev lag luam ceramic khoom ntawm tsawg tab sis tseem ceeb daim ntawv thov, feem ntau nyob rau hauv hluav taws xob insulators thiab tej cuab yeej. Nws yog tsim nyob rau hauv ob daim ntawv crystallographic, hexagonal boron nitride (H-BN) thiab cubic boron nitride (C-BN).

BN yog npaj los ntawm ntau txoj kev, suav nrog cov cua sov ntawm boric oxide (B2O3) nrog ammonia (NH3). Nws yog platy hmoov uas muaj, ntawm qib molecular, ntawm nplooj ntawv ntawm hexagonal rings uas swb yooj yim dhau ib leeg. Cov qauv no, zoo ib yam li cov pa roj carbon monoxide graphite (saib daim duab), ua rau H-BN yog ib qho khoom muag, lubrication; Tsis zoo li graphite, txawm li cas los xij, H-BN tau sau tseg rau nws cov hluav taws xob qis thiab thermal conductivity. H-BN feem ntau molded thiab ces kub nias rau hauv cov duab xws li hluav taws xob insulators thiab melting crucibles. Nws kuj tuaj yeem siv nrog cov kua nplaum ua cov txheej txheem kub-resistant rau metallurgical, ceramic, lossis polymer ua tshuab.

C-BN feem ntau yog ua los ntawm cov pob zeb me me los ntawm kev ua H-BN rau qhov siab heev (rau rau cuaj gigapascals) thiab kub (1,500 degree txog 2,000 degree C, lossis 2,730 degree txog 3,630 degree F) . Nws yog thib ob nkaus xwbpob zeb diamondnyob rau hauv hardness (mus txog qhov siab tshaj plaws ntawm 10 ntawm lubMohs hardnessscale) thiab, zoo lihluavtaws pob zeb diamond, feem ntau yog sib txuas rau cov hlau los yog hlau-ceramic txiav cov cuab yeej rau kev ua haujlwm ntawm cov hlau tawv. Ua tsaug rau nws qhov kub siab oxidation (siab dua 1,900 ° C, lossis 3,450 ° F), nws muaj qhov kub thiab txias ua haujlwm ntau dua li pob zeb diamond (uas oxidizes siab tshaj 800 ° C, lossis 1,475 ° F).