Transparent hydroxyapatite ceramics consolidated by spark plasma sintering

Highly transparent hydroxyapatite (HA) ceramics with nanosized grains were fabricated by spark plasma sintering at ∼900–1000 °C and 80 MPa. HA decomposition was not observed after sintering at 1000 °C for 10 min. The total forward transmission was more than 70% at 400 nm, and approached the theoretical value of 89% in the infrared wavelength range. The high transmission, indicating low light absorption and scattering, was attributed to the fine and dense microstructures.