An extrafine cobalt powder was hot compacted between 800 and 900°C. The powder was used in both its as-received and oxidized condition. The compacts were characterized by density measurements, hardness tests, impact and tensile strength, X-ray diffraction analysis, oxygen content determination and SEM. The increase in oxygen content brought about a pronounced rise in hardness and yield strength, whereas the increase in the hot compacting temperature had the opposite effect. Compacts with a high oxygen content were not susceptible to structure coarsening. The process of recrystallization occurred at 900°C in a non-oxidized material and resulted in a marked rise in ductility of the material.
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