Bioactive glass thin films deposited by magnetron sputtering technique: The role of working pressure

Bioglass coatings were prepared by radio frequency magnetron sputtering deposition at low temperature (150 °C) onto silicon substrates. The influence of argon pressure values used during deposition (0.2 Pa, 0.3 Pa and 0.4 Pa) on the short-range structure and biomineralization potential of the bioglass coatings was studied. The biomineralization capability was evaluated after 30 days of immersion in simulated body fluid. SEM-EDS, XRD and FTIR measurements were performed. The tests clearly showed strong biomineralization features for the bioglass films. The thickness of the chemically grown hydroxyapatite layers was more than twice greater for the BG films deposited at the highest working pressure, in comparison to those grown on the films obtained at lower working pressures. The paper attempts to explain this experimental fact based on structural and compositional considerations.