| 摘要 |
PROBLEM TO BE SOLVED: To provide hexagonal boron nitride powder in which coloring caused by by-products is suppressed, and capable of being imparted with high thermal conductivity and high insulation proof stress when being filled with a resin, and a method for producing the same.SOLUTION: Provided is the mixed powder of hexagonal boron nitride flocculated particles and hexagonal boron nitride simple particles having the average aspect ratio of 3 to 25, the average particle diameter of 4 to 30 μm and a simple particle ratio of 10 to 50%, in which BET specific surface area is 0.5 to 6.0 m/g and oil absorption is 100 g/100 or lower. The hexagonal boron nitride powder is obtained by heating a boron compound, a carbon source and an oxygen-containing calcium compound in specified ratios in a nitrogen atmosphere, are reacted till 1,550°C in such a manner that the carbon concentration in the reactant reaches 5 mass% or lower, and thereafter, heating is performed at 1,700°C or higher to produce hexagonal boron nitride. |
