Abstract
Hydroxyapatite (Ca_<10>(PO_4_6(OH_2,HA) is a bioactive material and is synthesized by four kinds of methods. The spark plasma system (SPS) is a promising method to produce advanced materials. Sintering and some chemical reactions are enhanced by SPS. This paper is concerned about the HA synthesis from the mixture of 6CaHPO_42H_2O and 4Ca(OH)_2by SPS. These two compounds are dehydrated under 600℃ and the mixture is turned into the composition of HA. Small crystals of HA were prepared without pressure at 600℃ by heating, but they were decomposed at this temperature for extended times or at higher temperatures. On the other hand, SPS enabled to form stable HA crystals at 600℃, and this growth was based on an effect of SPS. The HA formation was performed at 1000℃ at the high pressure such as 120 MPa. The high pressure of SPS could promote the crystal growth and the stability of HA compared with the decomposition products of HA.
