DENSE ISOTROPIC GRAPHITE FABRICATED BY HOT ISOCRATIC COMPACTION

摘要

Graphite bodies were prepared by the hot-isostatic-compaction process to obtain densities in the range of 2.20 to 2.24 per cm3 (95 to 99 percent of theoretical) with a high degree of isotropy. Of the graphite starting materials which were compacted and tested, a high-purity artificial powder and a commercial bulk (not powdered) material resulted in this combination of properties. The processing was accomplished at approximately 2700 C for SO min using a helium-gas pressure of 900 atm. The isotropic characteristics of the materials were determined by measurements of X-ray diffraction, electrical resistivity, and linear thermal expansion. On the basis of the property evaluations, samples of the most dense and isotropic materials were fabricated for irradiation testing at Battelle-Northwest.