Thermal spraying for bioceramic applications

Bioceramics are used in many applications and forms within the human body. Some major shortcomings of bulk ceramics concern their high variability in material properties and restriction to only limited forming operations. However, the excellent biocompatibility of many ceramics has provided a strong incentive to promote investigations for alternative manufacturing processes such as ceramic coating technology. Coatings may be applied by pyrolytic deposition, electrophoretic deposition, sintering, hot isostatic pressing, controlled oxidation, sol-gel techniques, physical vapour deposition (PVD), chemical vapour deposition (CVD), dipping processes and thermal spraying methods. The present work will focus on the thermal spraying of hydroxyapatite (HAp) onto metallic substrates which are intended for orthopaedic applications. It is intended to present the pertinent literature on HAp as it relates to thermal spraying, and also briefly detail some thermal spraying experiments. The thermophysical processes which occur during thermal spraying will be related to the structure/property relationships of the resultant coating.