Laser deposition of bioactive coatings by in situ synthesis of pseudowollastonite on Ti6Al4V alloy

The feasibility of obtaining bioactive coatings on Ti6Al4V alloy by laser deposition was studied. A Nd:YAG source was used under the following parameters: 65 or 70% of average power, 8 ms of pulse duration, 8 Hz of frequency and 0.7 mm/s of travel speed. A CaO-SiO2 powder mixture, with a molar ratio of 1:1, was projected to the metallic surface during the laser treatment. Due to the heat supplied by the laser, pseudowollastonite was the main compound formed in situ on the Ti6Al4V alloy samples as a result of the chemical interaction among calcium and silicon oxides and titanium from the alloy. A higher quantity of pseudowollastonite was formed on the sample treated at the highest average power used (70%). In vitro bioactivity assessment was performed by immersing pulsed laser-treated samples in a simulated body fluid (SBF) for 21 days. A dense Ca, P-rich layer was formed on the samples. The spherical morphology of the agglomerates formed is similar to the apatite formed on the existing bioactive systems.