Induction Heating Deposition of Calcium Phosphate Coating on Carbon/carbon composites for Biomedical Applications

摘要

Calcium phosphate coatings were deposited on carbon/carbon composites by induction heating method at 353K. The phase, morphology and composition of the calcium phosphate coatings were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM) and the adhesion strength of these coatings and the scratched morphologies were determined by the scratch test and stereomicroscope (STM). The results show that when the solution concentration is less than 0.00125 M and pH value is large than 6, the phase of as-prepared coating is hydroxyapatite with Ca/P molar ratio of 1.67 or OCP with Ca/P molar ratio of 1.33, and when the solution concentration and pH value are in the range of 0.05-0.0125M and 5-6, the as-obtained coating are blends of brushite, monetite or OCP. These coatings have a porous morphology and are very easy to be scratched off. When the solution concentration is large than 0.05 M and pH value is less than 5, the as-prepared coatings are monetite with Ca/P molar ratio of 1. Among these monetite coatings, the coating on C/C prepared in 0.2M solution have highest bonding strength with a critical load of on average 13 N.