Magnesium/Nano-hydroxyapatite Composite for Bone Reconstruction: The Effect of Processing Method

Nano-ceramic particles can serve as reinforcing agents for metallic materials to improve their mechanical properties. However, it is important to ensure chemical compatibility between the matrix and particles. In the present study, magnesium composites with and without nano-hydroxyapatite (nHA) particles were fabricated for bone reconstruction applications. Two different techniques were used, Conventional Sintering (CS) of powder compacts and Spark Plasma Sintering (SPS) of pre-compacted powder. Results showed that a 10 wt% addition of nHA particles to magnesium, followed by SPS improved the compression strength by 27%. CS did not lead to any significant improvement compared to SPS processing. X-ray diffraction data after CS revealed the formation of unfavorable phases due to chemical reactions between nHA particles and the magnesium matrix, while these phases were absent after SPS processing. The mechanical properties of the specimens fabricated by CS were much inferior to those processed using SPS. The shorter processing time associated with SPS leaded to reduced interaction between nHA particles and the Mg-matrix, compared to CS.