Effect of doping different Si source on Ca-P bioceramic coating fabricated by laser cladding.

The doping of silicon (Si) has been proved to improve the bioactivity of Ca-P ceramics. In light of this thinking, in the present study, Ca-P coatings with La2O3 by addition of 10 wt% SiO2 and 10 wt% diatomaceous earth (DE) were fabricated by laser cladding on Ti6Al4V, respectively. Coating doped without Si was also fabricated as the comparison group for the experiment. The effect of two different Si sources on the surface morphology, microstructure, microhardness, and bioactivity was systematically studied. The experimental results show that the Si-doped coating is of rough surface morphology, and the addition of DE significantly reduces the number of cracks and improves the microhardness. The X-ray diffraction results reveal that the amount of bioactive phase tricalcium-phosphate (TCP) and hydroxyapatite (HA) reaches maximum in the DE-doped coating. After soaking in simulated body fluid (SBF), the precipitate of bone-like apatite in the DE-doped coating is significantly higher than that of the other coatings.

Study on microstructure, microhardness, bioactivity, and biocompatibility of La2 O3 -containing bioceramic coating doping SiO2 fabricated by laser cladding.

To solve the lack of strength of calcium phosphate ceramic coatings in load-bearing applications, gradient Ca-P bioceramic coatings doped with La2 O3 and SiO2 are fabricated by laser cladding on Ti-6Al-4 V. The effect of SiO2 on microstructure, microhardness, bioactivity, and biocompatibility of coatings was investigated. The experimental results illustrate that the coating doped with La2 O3 and SiO2 has excellent metallurgical bonding. The XRD analysis confirms that the amount of hydroxyapatite and tricalcium phosphate in the coating reached maximum when doping amount of SiO2 is 10 wt %. SiO2 -doped coatings show a significantly higher bone-like apatite precipitation after immersion in SBF than that of other coatings. in vitro experiment also shows that coating with 10 wt % SiO2 is more suitable for the attachment and proliferation of MG63 cells, indicating that coating with 10 wt % SiO2 exhibits best bioactivity and biocompatibility. These results suggest that the addition of SiO2 improves the bonding strength, bioactivity, and biocompatibility of coatings.