Crystal chemistry of hydroxyapatite deposited on titanium by sputtering technique

Crystalline hydroxyapatite (HA) powder was coated on titanium substrate by radio frequency (RF) magnetron sputtering. The coating was homogeneous thin Aim and the thickness was 1 mum. Crystallinity of the HA coating was low and Ca/P ratio was high as 3.0. Particle sizes were 40 similar to 100 nm, and the crystallite size was calculated by 30 similar to 50 nm using an X-ray diffractometry (XRD) and a transmission electron microscopy (TEM). When the coating was heated at 800 degreesC for 1 h, the low crystalline HA grew up crystalline HA, and a diffraction pattern of CaO appeared. When the coating was immersed in pH 7.4 of bovine serum for 1 week, c-axis of HA increased.