DEVELOPMENT AND EVALUATION OF HOT ISOTATICALLY COMPACTED BORON NITRIDE.
Triannual rept. no. 1, 20 Jan-30 May 69,
BATTELLE MEMORIAL INST COLUMBUS OHIO COLUMBUS LABS
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Six commercial boron nitride powders have been prepared for hot isostatic compaction at conditions between 3000 and 4500 F 1650 and 2480 C at pressures between 15,000 and 30,000 psi. Scanning electron microscopy and the Coulter Counter were used to examine the particle size and shape of each of the materials, since the characteristics of these starting powders significantly affect final properties of the compacted materials. The powders exhibited generally similar particle morphology and a large size distribution which ranged from submicron to larger than 200-micron material. An alcohol and water rinse was used to reduce the amount of oxide phase, presumably B2O3, in some of the powders. Hydrostatic compaction of the powder materials at 100,000 psi at room temperature produced green compacts of sufficient strength for machining and densities of about 1.82 g per cm3, or 80 percent of theoretical. The initial series of hot isostatic compaction experiments is now being performed. Author
- Ceramics, Refractories and Glass