POSTDEPOSITION HEAT-TREATMENTS FOR ION-BEAM SPUTTER-DEPOSITED CALCIUM-PHOSPHATE COATINGS

Calcium phosphate coatings produced using the ion beam sputter deposit ion process are amorphous. To produce crystalline coatings, a series o f different post-deposition heat treatments were conducted. Heat treat ments conducted at temperatures less than 500 degrees C did not produc e crystalline phases in the coatings. A 500 degrees C post-deposition heat treatment provided the energy required to produce a hydroxyapatit e (HA)-type coating as determined using X-ray diffraction and Fourier transform IR spectroscopy (FTIR). Although post-deposition heat treatm ents can reduce the adhesion of a coating to its substrate, the 500 de grees C heat treatment did not decrease the coating bond strength. Hea t treatments conducted at 600 degrees C were found to produce crystall ine HA-type coatings but these heat treatments significantly reduced t he coating bond strength. Cracks were observed on the surface of the 6 00 degrees C heat treated coatings. FTIR analysis revealed a new absor ption band at 820 cm(-1) for the 600 degrees C heat treated coatings, suggesting the formation of a new phase.