No abstract

The recent surge in interest in the densification of calcium phosphate powders needs consideration of all the influencing factors. Spark plasma sintering with the primary contribution from the spark plasma and cold compaction that densifies from the large compaction pressures were considered. X-ray diffraction and Fourier transform infra-red spectroscopy characterized the powder and tablet to confirm the retention of the amorphous phase. Density was measured using the Archimedes method and the microstructure was viewed by scanning electron microscopy. The densified tablets were indented by nanoindentation to determine the hardness and elastic modulus. Reports on the density showed that the smallest contribution to density arose from vacuum, a marginally higher densification from the spark plasma effect, but the largest densification arose from the use of significantly higher pressures. Nanoindentation showed a small difference in elastic modulus between tablets densified at 25 °C and 200 °C, but a larger difference in the hardness.