Nano-structural bioactive gradient coating fabricated by computer controlled plasma-spraying technology

The poor mechanical property of hydroxyapatite was the major problem for load bearing and implant coating in clinical applications. To overcome this weakness, a bioactive gradient coating with a special design composition of hydroxyapatite (HA), ZrO2, Ti, bioglass was developed. This 120 μm coating with an upper layer of 30–50 μm porous HA produced by computer controlled plasma spraying which maintained energy level of the plasma which ensure proper melting of powder. The crystal size of the coating was 18.6–26.2 nm.