The amorphous phase in plasma sprayed hydroxyapatite coatings

Abstract

Atmospheric plasma spraying of hydroxyapatite was carried out to investigate the influence of the plasma spraying parameters on the formation of the amorphous phase. The amorphous phase was investigated with X-ray diffraction and optical microscopy. The results infer that dehydroxylation of the molten particle and a high cooling rate produce a larger amount of the amorphous phase. Crystalline regions of the coating consist of partially molten particles and elongated recrystallized areas. The amorphous phase is commonly found at the substrate interface. It is shown that the amorphous regions vary throughout the coating which clinically could affect the process of bone deposition and successful implant fixation