Fabrication and characterization of plasma-sprayed HA / SiO2 coatings for biomedical application

Fused silica powder was mixed with hydroxyapatite (HA) powder and plasma sprayed using a gas tunnel-type plasma jet. The influence of silica content (10 and 20 wt%) on the microstructure and mechanical properties of HA-silica coatings was studied. The microstructure and mechanical properties of HA-silica coatings using SUS 304 stainless steel as a substrate were investigated. SEM of cross-sectioned HA/SiO2 coatings showed that the HA coatings with 10 and 20 wt% SiO2 had a dense structure with low porosity compared to the pure HA coatings. However, as the amount of silica was increased, the coatings became denser, harder and exhibited high abrasive wear resistance. The presence of silica significantly improved the adhesive strength of HA/SiO2 coatings mainly due to the increase in bonding strength of the coating at the interface.