Preparation of improved hydroxyapatite coating on HT-C/C by modified induction heating deposition/hydrothermal treatment technologies

Abstract

Monetite coatings were produced on H₂O₂ treated carbon/carbon composites by induction heating deposition in the presence or absence of ultrasonic agitation of the bath and then converted to hydroxyapatite coatings undoped with other cations by ammonia hydrothermal treatment. The phase, morphology and chemical composition of the as achieved monetite and hydroxyapatite coatings in the presence/absence of ultrasound were characterised by XRD, SEM and TR-XRF. The adhesion of monetite and hydroxyapatite to the H₂O₂ treated carbon/carbon substrates was evaluated by a scratch test. The results showed that no obvious differences in the phase and composition for the as obtained coatings were found. However, ultrasonic bath could produce denser and better bonded coatings. The ultrasonicated coatings showed an average critical load of 38 N, which is nearly three times as high as that of the hydroxyapatite coating without ultrasonic bath. The failure position of the hydroxyapatite coating occurred in the coating, and no delamination was observed.

Keywords:

• Adhesion
• Coating
• Carbon
• Hydroxyapatite

This work was supported by the National Natural Science Foundation of China (grant no. 50702034) and the Shenzhen Science and Technology Research (grant no. PT200805200295A).