氫氧磷灰石之合成及其高壓下行為研究

Synthesis of Hydroxyapatite and Its High-pressure Behavior

For the synthesis of hydroxyapatite (HA) crystals from aqueous solutions, three preparation methods were employed in the study. From the experimental processes and the characterization of the crystalline phases it was concluded that the pH and Ca/P ratio of the reaction solutions are critical for the purity of the product and its crystallographic characteristics. With respect to high-pressure study, XRD and Raman spectroscopy were used to characterize the possible change of HA phase. Although the progressive broadening and shift in XRD peaks as well as Raman modes with increasing pressure were observed, no extra phases were observed under high-pressure condition. In addition, HA samples did not exhibit any phase transition and amorphization at pressures up to around 10 GPa. Fits of data with the second-order Birch-Murnaghan equation yield bulk modulus of K0=97GPa, identical to those values reported elsewhere.本研究採用三種濕式化學合成方法來製備氫氧磷灰石。實驗過程中發現水溶液中的鈣磷比例與酸鹼度將會影響純度、結晶相與粉晶特性。本研究也利用X光繞射儀與拉曼光譜儀來分析氫氧磷灰石的高壓行為。隨著壓力的增加，粉晶的X光繞射譜與拉曼光譜都未出現新的波峰，但都呈現逐漸寬化的趨勢，然而加壓到10GPa的壓力時仍未出現相轉變或非晶質化等現象。利用Birch-Murnaghan方程式配合高壓研究數據，得知本氫氧磷灰石的體彈模量K0=97GPa，這個數值與前人研究甚為符合。