Composition and microstructure of chemically vapor-deposited boron nitride, aluminum nitride, and boron nitride + aluminum nitride composites

Article abstract of DOI:10.1111/j.1151-2916.1991.tb06879.x

The composition and microstructure of dispersed-phase ceramic composites containing BN and AlN as well as BN and AlN single-phase ceramics prepared by chemical vapor deposition have been characterized using X-ray diffraction, scanning electron microscopy, electron microprobe, and transmission electron microscopy techniques. Under certain processing conditions, the codeposited coating microstructure consists of small single-crystal AlN fibers (whiskers) surrounded by a turbostatic BN matrix. Other processing conditions resulted in single-phase films of AlN with a fibrous structure. The compositions of the codeposits range from 2 to 50 mol% BN, 50 to 80 mol% AlN with 7% to 25% oxygen impurity as determined by electron microprobe analysis.