Patent ID: 6624339
Filing Date: 2003-09-23
Classification: G21F,Y02E

Abstract:
A method for preparing a phosphosilicate apatite having the formula (I):MtCaxLnyHfwPuzâˆ’w(PO4)6âˆ’u(SiO4)uF2â€ƒâ€ƒ(I) wherein:M represents an alkaline metal, Ln represents at least one cation selected from lanthanides, and t, x, y, z, w and u are such that: 0&lE;t&lE;1, 8&lE;x&lE;10, 0&lE;y&lE;1, 00&lE;w0and the total number of positive charges provided by the alkaline metal, CaxLn, Hf and Pu cations are equal to 20+u; said method comprising: a) preparing a first mixture of powders containing plutonium dioxide, calcium pyrophosphate, a silicone compound and optionally one or more compounds selected from alkaline metal compounds, hafnium compounds and lanthanide compounds; b) preparing a second mixture of powders by mixing the first mixture of powders with at least one powdered fluorinated reagent; c) grinding said second mixture of powders to a particle size of less than 50 &mgr;m; d) compressing the ground second mixture of powders in a mould under pressure from 100 to 500 MPa to obtain a compressed product, and e) submitting said compressed product to a sintering-reaction in a neutral or reducing atmosphere, at atmospheric pressure and at a temperature of 1500 to 1600Â° C. to obtain a sintered product.