Aluminum nitride and boron nitride composite ceramic and preparation method thereof

The invention relates to aluminum nitride and boron nitride composite ceramic and a preparation method thereof.The preparation method comprises the following preparation steps that S10, aluminum nitride powder, boron nitride powder, calcium oxide powder and yttrium oxide powder are mixed, the obtained mixed powder is put into a ball milling tank, meanwhile, grinding balls and a solvent are added for ball milling, and powder slurry is formed; step S20, performing vacuum drying on the powder slurry to form composite powder; and S30, the composite powder is subjected to hot pressed sintering under the protective atmosphere. According to the preparation method, product impurities can be effectively removed, the oxygen content is remarkably reduced, the aluminum nitride grain boundary is purified, and the prepared aluminum nitride and boron nitride composite ceramic has excellent heat conduction performance and can be widely applied to the field of heat dissipation devices with complex shapes and high heat conduct