An electron microscopic study of the formation of amorphous calcium phosphate and its transformation to crystalline apatite.

摘要: Dried amorphous calcium phosphate (ACP) can exist in discoidal and spheroidal forms. The disk-shaped particles are most prominent dried ACP specimens isolated immediately following precipitation. spherical forms become dominant taken from older suspensions. disk-like morphology is a result of sample drying. Spherules also arise during the drying step but present native suspension as well. Both disks spherules appear to have common solution progenitor form highly hydrated aggregate unknown morphology. formation crystalline apatite intimately connected with ACP. first crystals on surface contact disks. In case spherules, initial increase size generate additional by secondary nucleation until enveloped apatite. However, when conversion completed, does not fill appreciably space previously occupied dissolved spherules. These observations do support concept anin situ solid state this case, indicate heterophase transition supported solution-mediated ion translocation process. occurrence suggest that directly progenitor.