Boron nitride particles of spherical geometry and process of making

A spherical boron nitride powder consisting essentially of spherical agglomerates of non-spherical shaped boron nitride particles, where the agglomerates have a tap density of about 0.8 g/cc or less.

A boron nitride powder comprising agglomerated particles of spherical geometry, wherein said spherical agglomerate particles have an average particle size of about 1 to 500 microns in diameter, wherein the particles have a surface layer comprising an organic binder and/or a decomposition product thereof, and wherein the spherical agglomerates particles are prepared by (a) spray drying an aqueous slurry of non-spherical shaped boron nitride particles with a binder, and (b) sintering the spherical boron nitride particles.

A process for forming a boron nitride powder comprising agglomerated particles of spherical geometry having an average particle size of about 1 to 500 microns in diameter and a tap density of about 0.8 g/cc or less, said process comprising the steps of:

• mixing an aqueous slurry including irregular shaped boron nitride particles, water, and an organic binder;
• spray drying the aqueous slurry into a powder composition of agglomerated boron nitride particles;
• and sintering the boron nitride powder.