Research on the In Situ Fabrication of Bioceramic Composite Coatings by Laser Cladding
Hydroxyapatite(HAP) has excellent osteoconductive properties. By controlling the Ca/P ratio better biphasic calcium phosphate ceramics can be produced than pure HAP ceramics. β- calcium pyrophosphate(β-Ca2P2O7) is a new biodegradable ceramic material and its biological response is quite similar to HAP. Obtaining HAP and other bioactive calcium phosphate ceramic coatings has been a popular research field in the past. In our research a new bioceramic composite coating was obtained by laser cladding with pre-depositing mixed powders of CaHPO4·2H2O and CaCO3 directly on the metal substrate. Its main constituents are HAP and β-Ca2P2O7. The microstructure of the coating consists of minute granular HAP that is distributed among the overlapped club-shaped or needle-like β-Ca2P2O7. The hardness distribution in the cladding layer is even and its value is much higher than that in the substrate. There is a bonded structure of the epitaxial planar growth between the substrate and cladding layer, and both a typical cellular microstructure in the middle and an equiaxed microstructure at the top of the cladding layer.
Xingdong Zhang, Xudong Li, Hongsong Fan, Xuanyong Liu
Y. C. Wang et al., "Research on the In Situ Fabrication of Bioceramic Composite Coatings by Laser Cladding", Key Engineering Materials, Vols. 330-332, pp. 625-628, 2007