... greater than the graphite crucible. Boron nitride crucible is produced by boron nitride block which is sintered with boron nitride powder according to ... °C, up to 900 °C.3: Long service life. Boron nitride crucible,Boron nitride crucible,Boron nitride crucible,Boron nitride crucible,Boron nitride crucible,Boron nitride crucible,Boron nitride crucible,Boron nitride crucible,Boron nitride crucible