Bonelike apatite formation on various kinds of ceramics and metals

An uniform layer of apatite was formed on ceramic and metal substrates by placing them on CaO-SiO2-based glass particles soaked in a simulated body fluid (SBF) at 36.5 degreesC, and then soaking the substrates in an aqueous solution with ion concentration 1.5 times those of SBF at 36.5 degreesC, During the first treatment, the induction period required for apatite nucleation on the surface was considerably affected by the kind of substrate. The induction period was shortened with increasing silicon content in substrates, For silicon single crystal, it was 0 d. This indicates that silicon single crystal has the ability to induce apatite nucleation by itself. The uniform apatite layer was also formed on ceramics and metals with various shapes including cloths, fibers, and beads as well as rectangular substrates.