X-ray study of the recrystallization of copper powder during sintering

Abstract

1. In its initial state, autoclaved copper powder differs from electrolytic copper powder not only as regards particle size and shape, but also structure (autoclaved powder has a coarser block structure). 2. A marked difference in the structures of these powders is retained after briquetting and annealing up to a temperature of 900°C. 3. The effect of the degree of cold deformation during briquetting on the onset temperature of recrystallization of the particles of powdered material is qualitatively similar to that of deformation on the onset temperature of recrystallization of cast material. 4. Judging from the appearance of the first points on the powder pattern lines, the onset temperature of recrystallization of autoclaved Cu powder is 75–100° below that of electrolytic powder. 5. The onset temperature of recrystallization in Cu powder during sintering virtually coincides with that in cast copper. However, the completion of recrystallization and the beginning of corecrystallization in cermet copper is displaced upwards by 100–300° in comparison with cast material. This is indicated primarily by measurements of the line widths.