US Patent 7341702 Process for producing boron nitride

A process for producing boron nitride of high purity and high thermal conductivity, wherein a oxygen-containing boron compound is reacted with a nitrogen-containing source in the presence of a dopant at a temperature of at least 1000° C. for at least one hour, and wherein the dopant forms metal borate impurities with a vaporizing temperature that is lower than the highest processing temperature in the process.