| 摘要 |
PURPOSE:To readily obtain high-purity boron nitride powder, by decomposing a metal boride in a nitrogen stream while heating by electromagnetic induction heating to form powdery boron nitride. CONSTITUTION:A crucible 3, containing a crushed metal boride 4, e.g. zirconium boride, and having small holes at the bottom thereof is provided in a quartz tube 2 having a high-frequency electromagnetic induction heating coil 1 provided around the outer periphery thereof. Nitrogen gas is then passed from the bottom to the top of the quartz tube 2 and the metal boride 4 is heated to about 1,200-1,400 deg.C by electromagnetic induction heating at the same time to form fine particulate boron nitride 6 in the form of white smoke sticking to a part at a low temperature around a water-cooled jacket at the top of the quartz tube 2. Thereby the individual metal boride is made to generate heat by electromagnetic induction heating and the contamination of impurities from an auxiliary heating element, etc., can be prevented.
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