Morphological Study of HAP Coated Alumina by Sol-Gel Method for Orthopedic Implants

Abstract

Hydroxyapatite (HAP) Ca10(PO)6(OH)2 is widely used as a bioactive ceramics since it forms a chemical bonding to bone. The dominant requirement for the development of HAP coatings on metallic implants is the preparation of stoichiometric material with required chemical and phase composition (Ca/P molar ratio 1.67). In this work the preparation of HAP films by sol-gel method on alumina and its characterization are described. The coating was done using dip-coating method, starting from a colloidal suspension of hydroxyapatite. Compound formation of HAP is confirmed using GIXRD. By Energy Dispersive X-Ray spectroscopy (EDX) analysis Ca/P ratio of the HAP was found to be 1.657 which is very close to the stoichiometric value of 1.67. The FTIR spectra of the coatings were used to determine the presence of chemical species of the coatings. Surface Characterization has been carried out using SEM & AFM techniques. Wettability study has been carried out using OCA and it was found that hydrophobicity decreases with the increase in HAP thickness. Corrosion studies have been carried out using electrochemical analyzer (ECA) in Ringer solution and best corrosion resistance was observed for the thickest sample. The paper discusses the variations in surface morphology using SEM, AFM & EDX and its effect on biocompatibility.