Non-Equilibrium Synthesis of Whitlockite Assisted by Localized H2O Vapor Pressure.

Whitlockite (Ca18Mg2(HPO4)2(PO4)12) has attracted considerable attention in the fields of bone grafting and bone regeneration due to the presence of magnesium ions and the HPO4 2- group. However, conventional methods for synthesizing whitlockite require strict conditions and often result in excessive particle growth and compositional inhomogeneity. Here, we report the ultrafast and precisely controlled synthesis of whitlockite using a photothermal shock process induced by intense pulsed light (IPL). The formation of the whitlockite phase indicates that the precursor particles underwent a transient liquid phase and ion diffusion during IPL irradiation, facilitating the emergence of the new phase. Furthermore, we demonstrate that the H2O-rich, high-pressure environment generated at the interface of carbon microheaters and the hydrated precursor plays a key role in whitlockite formation. This simple and rapid IPL-assisted approach provides an effective strategy for calcium phosphate crystallization and bioceramic fabrication, opening new avenues for controlled synthesis of complex phosphate phases.