Boron nitride sintered body, composite body, method for producing said boron nitride sintered body, method for producing said composite body, and heat dissipation member

A method for manufacturing a boron nitride sintered body, the method comprising:

• a sintering step of molding and heating a blend containing a lump boron nitride powder and a sintering aid to obtain a boron nitride sintered body including coarse particles each having a length of 20 μm or more in a cross-section and fine particles smaller than the coarse particles.

A method for manufacturing a boron nitride sintered body, the method comprising:

• a raw material preparation step of firing a mixture containing boron carbonitride and a boron compound in a nitrogen atmosphere to obtain lump boron nitride having an average particle diameter of 10 to 200 μm;
• and
• a sintering step of molding and heating a blend containing the lump boron nitride and a sintering aid to obtain the boron nitride sintered body including coarse particles each having a length of 20 μm or more in a cross-section and fine particles smaller than the coarse particles.