Hydroxyapatite layers prepared by sol-gel assisted electrostatic spray deposition

Hydroxyapatite (HAP) thin films were prepared by the sol-gel assisted electrostatic spray deposition (ESD) using calcium nitrate and phosphoric acid as starting materials. Methanol was used as solvent in the precursor solution. Final annealing was done at 500 °C for 30 min in air. Crystallinity, chemical structure, and surface morphology of the films were analyzed. Well-crystallized hydroxyapatite films were obtained by final annealing at 500 °C. Eighty degree celsius was the ideal substrate temperature for preparing smooth and dense hydroxyapatite films.