Improvement of the Mechanical Properties of Spark Plasma Sintered HAP Bioceramics by Decreasing the Grain Size and by Adding Multi-walled Carbon Nanotubes

摘要

Composites based on HAP and oxidized multi-walled carbon nanotubes (o-MWCNT) and monophase HAP materials were processed by spark plasma sintering. Starting from stoichiometric nano-sized HAP powder, monophase hioceramics were obtained with a density close to the theoretical one and with an average grain size of several hundred nanometers to micron dimensions. It was shown that decreasing the sintering temperature resulted in a decrease of the grain size, which affected an increase in the fracture toughness and hardness. The fracture toughness of an HAP/ o-MWCNT bioceramic processed at 900 °Cfor only 5 min was 30 % higher than that of monophase HAP materials obtained under the same conditions. The addition of MWCNT during SPS processing of HAP materials caused a decrease in the grain size to the nano-dimension, which was one of the reasons for the improved mechanical properties.