Wetting andin vitrobioactivity of laser processed CaP coating with presence and variation of SiO2on Ti–6Al–4V

Calcium phosphate bioceramic and SiO2–CaP bioceramic composite coatings were prepared on Ti–6Al–4V substrates by laser cladding method. Surface energy components were calculated and the wettability of the coatings in simulated body fluid (SBF) was investigated. In vitro bioactivity of the coatings were performed by immersing in SBF and analysed for the precipitation of hydroxyapatite (HA). The effects of SiO2 content on the wettability and in vitro bioactivity of the bioceramic composite coatings were investigated. The surface energy values increased as the percentage of SiO2 in the coating precursor increased, resulting in decrease in contact angle with SBF for improved wettability. X-ray diffraction results indicated that after immersion in SBF for more than three days, 17 wt-%SiO2–CaP and 25 wt-%SiO2–CaP samples possessed highly intense peaks of HA than 100 wt-%CaP sample. Furthermore, in vitro bioactivity assays show that the SiO2–CaP bioceramic composite coatings possess a higher HA precipitation rate than CaP coating and Ti–6Al–4V control.