Synthesis and Phase Transformation of Ca₁₀(PO₄)₆S Sulfoapatite by Solid‐state Reaction with Sulfur Vapor

The calcium sulfoapatites, Ca₁₀(PO₄)₆S, could be successfully synthesized only using oxide starting materials with sulfur vapor under H₂ atmosphere instead of toxic H₂S gas, and then the dependence of phase transformations and luminescent properties on the post‐annealing conditions was investigated. Ca‐sulfoapatites were transformed to Ca‐hydroxyapatites, Ca₁₀(PO₄)₆(OH)₂ and β‐Ca₃(PO₄)₂ by post‐annealing at H₂ and air atmosphere, respectively. Luminescent properties of europium doped these apatites strongly depended on the annealing temperatures and atmosphere, resulting in blue and red emissions.

Keywords:

• hydroxyapatite
• optical properties
• phase transformation, solid‐state reaction
• sulfoapatite

This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MOST). (No. R01‐2005‐000‐10530‐0).