Surface Dissolution of Hydroxyapatite with Different Composition
The effect of Ca/P ratio on surface dissolution of hydroxyapatite [Ca10(PO4)6(OH)2, HA] in distilled water was investigated. The stoichiometric HA powder and desired Ca/P ratio achieved by adding either Ca3(PO4)2 for a Ca/P ratio of 1.62 or CaO for a Ca/P ratio of 1.72 were used as starting materials. Dense HA ceramics were obtained by sintering at 1200 oC for 2 h in air with under moisture protection. The sintered specimens were then placed into 40 ml of pH 7.4 distilled water. After immersing for certain period of time at 37 oC, crystal structure, weight loss and microstructure of the specimens were investigated. As increasing the immersion time, circular cavities similar to that normally attributed to osteoclast resorption lacunae were observed. As a result, it was found that the dissolution of HA along the grain boundary and subsequently microstructural disintegration was more distinct in 1.62 and 1.72 samples compared to pure HA.
Chunli BAI, Sishen XIE, Xing ZHU
D. S. Seo et al., "Surface Dissolution of Hydroxyapatite with Different Composition", Solid State Phenomena, Vols. 121-123, pp. 987-990, 2007