Effect of bio-calcium oxide on the morphology of hydroxyapatite

Abstract

<p>A study of the Hydroxyapatite (HAp) synthesis through a hydrothermal process was carried out. Bio-Calcium oxide (CaO) obtained by heat treatment of sand dollar was used in the synthesis at different proportions to react with monetite (CaHPO₃). Structural and chemical characterization of the samples was carried out using scanning electron microscopy (SEM), X-ray diffraction; Infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). In each sample were observed different morphologies such as agglomerates, hexagonal particles, epitaxial growth, and fibers. O, Ca, P, C and small amounts of Mg and Si were the main chemical components of the sharp morphologies. The hydroxyapatite, whitocklite, portlandite and calcite were the crystalline phases found in each of the samples analyzed. Two different growth shapes of HAp single crystals were found using transmission electron microscopy. The HAp single crystal with six well-defined prismatic faces was reveled to grow along side the &lt;1 0 –1 0&gt; crystallographic direction. The HAp single crystal with fiber morphology grew alongside c-axis. However, both morphologies of HAp single crystals present a ratio Ca/P less compared with the stoichiometric ratio (Ca/P=1.67).</p>