Various carbonated calcium phosphate powders were synthesized by aqueous precipitation and ceramics con solidation by spark plasma sintering (SPS) at very low temperature was investigated. The objective was to preserve low crystallinity and avoid material decarbonation. SPS at low temperature only leads to little or no sintering when crystalliz.ed powders are used. Amorphous powders are required. ln this case, consolidation occurs at temperatures below 150 •c. lt is accompanied by crystallization of the amorphous phase into calcium deficient carbonated apatite Ca,o x y(PO ◄)6 x y(HPO.).(COs)y(OHh x y 2:z(CO 3).. The resulting ceramics are mi croporous and highly cohesive with good mechanical properties (fl exural strength = 18 MPa). The sintering mechanism, called "crystal fusion", is based on solid state diffusion of chemical species at the grain boundary and crystal growth wi thin the amorphous particles. These bioceramics that mimic the composition of the bone minerai are expected to have a higher bioreactivity than well crystallized carbonated hydroxyapatite ceramics obtained by conventional sintering.

Influence of carbonation on the low-temperature consolidation by SparkPlasma Sintering of carbonated calcium phosphate bioceramics. (2020) Ceramics International, 46 (5). 5799-5810.