Effect of copper (Cu 2+ ) inclusion on the bioactivity and antibacterial behavior of calcium silicate coatings on titanium metal

The present study is an investigation of the effect of copper (Cu ) inclusion on the bioactivity, antibacterial behavior, corrosion resistivity and leaching characteristics of calcium silicate coatings on titanium metal. The synthesis of stoichiometric CaSiO and five different concentrations of Cu substitutions in CaSiO was carried out. The incorporation of Cu in the crystal lattice of CaSiO was investigated by means of the Rietveld refinement technique. The results from the structural investigation have shown that stoichiometric CaSiO crystallizes in the monoclinic system (space group = P /a and unit cell parameters a = 15.4241 (5) Å, b = 7.3276 (7) Å and c = 7.0620 (8) Å with α = 90°, β = 95.404° and γ = 90°) and are in good agreement with the literature data for crystalline CaSiO . The substitution limit of Cu in the crystal lattice of CaSiO was determined as 4.399 wt% of Cu and the increased level of Cu substitution resulted in the formation of an additional phase in the form of tenorite (CuO). The fabrication of stoichiometric CaSiO and Cu substitutions in CaSiO coatings on Ti metal was achieved through an electrophoretic deposition technique and no change in the phase behavior of the coatings was noted until the heat treatment temperature reached 800 °C. Immersion tests of CaSiO coatings in simulated body fluid solution resulted in the formation of an apatite layer within 3 days of immersion. Antibacterial tests showed that pure CaSiO powders did not exhibited any antibacterial activity whereas the presence of Cu in CaSiO resulted in good activity against E. coli and S. aureus. Potentiodynamic polarization tests performed on the Cu doped CaSiO coatings resulted in its better corrosion resistivity when compared to the pure metal and dissolution tests performed on coatings resulted in the leaching of Cu at low levels.