To accelerate the bone growth around a metallic implant and to achieve the mechanical characteristics needed for biomedical applications, a hydroxyapatite/pure titanium (HA/Ti) composite coating was produced on NiTi alloy substrate by laser cladding. The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. Owing to decomposition of HA under irradiation of high power laser, the microstructures of coating were mainly composed of CaO, CaTiO 3 , titanium phosphide and HA phases. In vitro experimental result demonstrated that HA/Ti composite coating made the bioactivity of NiTi alloy improved remarkably while restraining Ni ion from releasing.

Brush electroplated Ni-polytetrafluoroethylene (PTFE) composite coatings with uniform distribution of PTFE particles in the nanocrystalline Ni matrix were prepared by changing the bath temperature. The effects of the bath temperature on the deposition, microstructure and tribological properties of the composite coatings were investigated. Experimental results show that the PTFE content in coatings, deposition rate and the tribological properties trend to increase with increasing bath temperature, and the composite coating prepared at the bath temperature of 40uC reaches a maximum in surface morphology. However, it is difficult to successfully prepare the composite coatings when the bath temperature is above 40uC owing to their poor adhesion to the substrate. Therefore, some measures should be taken when the composite coatings are prepared at the bath temperatures above 40uC.