Comparison of Hydroxyapatite Coatings Produced Different Powder Morphology

Metallic biomaterials are attractive materials for application orthopaedic implants because of their significant mechanical properties. However, metallic biomaterials are generally biocompatible and are required to coat with osteoconductive coatings such as hydroxyapatite (HA) that is natural mineral found in bone tissue. Hydroxyapatite (HA), formulated as Ca10(PO4)6(OH)2, which has a great osteoconductivity properties with human organism and formed an inorganic part of the bone is used as a biomaterial to repair hard tissues and their configurations. Different methods such as plasma spraying, High velocity oxy-fuel (HVOF), laser, electrophoresis, dip coating, sol-gel methods are widely used to coat the metallic implant materials. On one hand plasma spraying is the most common and economical method for industrial applications, on the other hand, high process temperature of plasma spraying causes defects on HA structure and occurrence of secondary phases. The main effect on the decomposition of HA during spraying is affected by the main process parameters such as plasma gases, process voltage and current and feedstock materials. In this study, HA powders having different size distrubition and morphology were used to compare their response for decomposition process. Furthermore, different plasma spray systems were utilized to compare coating structure after spraying. Coating were fabricated grade 5 titanium alloy and coatings were analysed using Scanning Electron Microscope and X-Ray Diffraction methods