Effects of La₂O₃contents on microstructure and properties of laser-cladded 5 wt% CaB₆/HA bioceramic coating

In the present work, 5 wt% CaB₆/hydroxyapatite (HA) bioceramic coatings with different La₂O₃contents (0-0.6 wt%) have been fabricated by a laser cladding technique on Ti-6Al-4V. The effects of La₂O₃contents on microstructure and properties of the laser-cladded 5 wt% CaB₆/HA coatings have been carefully investigated. The results show that the microstructure is obviously refined, and the structure is relatively uniform after doping 0.2-0.4 wt% La₂O₃. As the La₂O₃content increases, the corrosion resistance are found to increase firstly and then gradually decrease. The x-rays diffraction analysis confirms that the amount of HA and TCP (calcium phosphate) in the coating reaches maximum after doping 0.2 wt% La₂O₃. The La₂O₃-doped coatings show a significantly higher bone-like apatite precipitation after immersion in simulated body fluid compared with La₂O₃-free coating. In vitro experiment also shows that 5 wt% CaB₆/HA bioceramic coatings with 0.2-0.4 wt% La₂O₃are more suitable for the attachment and proliferation of MG63 cells, exhibiting superior bioactivity and biocompatibility.