Spark plasma sintered AlN-BN composites and its thermal conductivity

A series of samples of hexagonal boron nitride-aluminum nitride ceramic composites with different amounts of CaF₂ as sintering aid were prepared by spark plasma sintered at 1700–1850 °C for 5 min. The addition of CaF₂ effectively lowered the sintering temperature and promoted the densification of AlN-BN composites. With the increase of sintering temperature, the density increased, and the contiguity of AlN grains enhanced in AlN-BN composites. Thermal conductivity of AlN-BN composites increased with the increase in CaF₂ content and sintering temperature, and there is a maximum value of 78.6 W·m⁻¹·K⁻¹ when the sample with 3wt% CaF₂ sintered at 1800 °C. Funded by New Century Excellent Talents in University of the Ministry of Education of China (No. NCET-04-0722) and Doctoral Fund of Ministry of Education of China (No. 20060497003)