Sintering behavior and apatite formation of diopside prepared by coprecipitation process.

Sintering behavior and bioactivity of diopside, CaMgSi(2)O(6), prepared by a coprecipitation process were examined for its biomedical applicability. As-prepared powder was synthesized by adding aqueous ammonia to an ethanol solution containing Ca(NO(3))(2).4H(2)O, Mg(NO(3))(2).6H(2)O, and Si(OC(2)H(5))(4) and characterized by means of TG-DTA, XRD, and TG-MS. The dried powder was X-ray amorphous and crystallized into diopside at 845.5 degrees C. The glass network formation by SiO(4) tetrahedra was almost completed below 800 degrees C. The bioactivity of the diopside prepared by sintering the compressed powder at 1100 degrees C for 2h was evaluated by immersion of the sintered body in a simulated body fluid (SBF) at 36.5 degrees C. Leaf-like apatite particles were found to be formed on the surface of the sintered body and grew with passage of soaking time. This apatite-forming behavior in the SBF is related to the dissolution of Ca(II) ions from the sintered body in the early stage of immersion. Thus, diopside prepared by the coprecipitation process using the metal alkoxide and the metal salts was found to have an apatite-forming ability.