Metastable Intermediate Phase during Phase Transformation of Calcium Phosphates

摘要

Phase transformation of calcium phosphates from amorphous to crystalline phases around neutral pH proceeds via direct structure conversion using non-ionic elementary units. This transformation inevitably forms metastable intermediate-structured phase(s) between the two end phases. In addition to conventional calcium phosphate phases appearing in the transformation, new unknown phases were observed. They did not correspond to simply poor crystalline materials of conventional phases and instead had particular structures. One was pseudo-OCP, which lacked the HPO4-OH layers in the conventional OCP structure.