Reaction-Bonded Boron Nitride-Aluminum Nitride Ceramic Composites

Abstract

Hexagonal boron nitride-aluminum nitride (h-BN-AlN, 75-25 wt%) ceramic composites are synthesized by reaction bonding. Metallic component-free, relatively dense composites are obtained by using h-BN and Al as starting materials and by optimizing sintering conditions. In comparison with reaction-bonded BN, higher bending strength, 98 MPa, and higher thermal conductivity, 66 W/(m·K), are attained for a Y 2 O 3 -added BN-AlN composite. A low thermal expansion coefficient of 2.6×10 -6 /K is also achieved.