Microstructure of explosively compacted aluminum nitride ceramic

Observations are reported of the microstructure of aluminum nitride (A1N) ceramic produced by explosive consolidation of the powder. Similarities between the grain structure of the compact and the starting powders are striking. Grain growth does not occur during densification and the 0.1 ..mu.. particle size of the powder is retained, although considerable deformation is introduced into individual grains. Of particular interest is an intergranular phase which appears throughout the compact. Observations in the transmission electron microscope indicate that this phase is amorphous.The influence of this glassy intergranular phase on bonding is discussed. 5 figures.