Synthesis of new apatite phases by spray pyrolysis and their characterization

This paper describes the synthesis of some apatite compounds, called britholites, by an aerosol pyrolysis technique, which compared to conventional methods of solid-state chemistry, presents the advantages of reducing noticeably the temperature and the duration of the treatment. Britholites are minerals based on Ca(10-x)Ln(x)(PO4)(6-x)(SiO4)(x)X-2 formula (with X = F-, OH-, X-2 = O2-); they are promising materials for nuclear waste storage. In a second part we have synthesized and characterized a new apatite phase where the substitution of calcium by barium in britholite leads to a monophased solid solution Ca9-xBaxNd(PO4)(6-x)(SiO4)F-2 for 6 < x < 9. The possible interest of this new material is discussed. (C) 2001 Kluwer Academic Publishers.