Phase Transformations in Laser Treated Hydroxyapatite Coatings

Hydroxyapatite (HA) was plasma sprayed onto titanium alloy substrates. One set of samples had a crystalline content of 25%, the other set, 30%. The coatings were then subjected to CO2 laser treatments at different power levels and scanning rates while surface temperatures ware monitored with a pyrometer. XRD analysis verified the crystallinity of HA and the content of amorphous calcium phosphate as well as foreign phases. Optical microscopy revealed the microstructure and depth of the laser modified zone.