Effects of La2O3 contents 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 La2O3 contents (0-0.6 wt%) have been fabricated by a laser cladding technique on Ti-6Al-4V. The effects of La2O3 contents 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 La2O3 content 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% La2O3 are more suitable for the attachment and proliferation of MG63 cells, exhibiting superior bioactivity and biocompatibility.