abstract
Thin (380-510 nm) films of a low silica content bioglass with MgO, B2O3, and CaF2 as additives were deposited at low-temperature (150A degrees C) by radio-frequency magnetron sputtering onto titanium substrates. The influence of sputtering conditions on morphology, structure, composition, bonding strength and in vitro bioactivity of sputtered bioglass films was investigated. Excellent pull-out adherence (similar to 73 MPa) was obtained when using a 0.3 Pa argon sputtering pressure (BG-a). The adherence declined (similar to 46 MPa) upon increasing the working pressure to 0.4 Pa (BG-b) or when using a reactive gas mixture (similar to 50 MPa). The SBF tests clearly demonstrated strong biomineralization features for all bioglass sputtered films. The biomineralization rate increased from BG-a to BG-b, and yet more for BG-c. A well-crystallized calcium hydrogen phosphate-like phase was observed after 3 and 15 days of immersion in SBF in all bioglass layers, which transformed monotonously into hydroxyapatite under prolonged SBF immersion. Alkali and alkali-earth salts (NaCl, KCl and CaCO3) were also found at the surface of samples soaked in SBF for 30 days. The study indicated that features such as composition, structure, adherence and bioactivity of bioglass films can be tailored simply by altering the magnetron sputtering working conditions, proving that this less explored technique is a promising alternative for preparing implant-type coatings.
keywords
PULSED-LASER DEPOSITION; CRYSTALLINE HYDROXYAPATITE; SILICATE-GLASSES; COATINGS; BONE; PHOSPHATE; CERAMICS; SPECTROSCOPY; SIMULATION; CHEMISTRY
subject category
Engineering; Materials Science
authors
Stan, GE; Pasuk, I; Husanu, MA; Enculescu, I; Pina, S; Lemos, AF; Tulyaganov, DU; El Mabrouk, K; Ferreira, JMF
our authors
Isabel Alexandra Fernandes Lemos
Post-doc Fellowship
José Maria da Fonte Ferreira
Retired Professoracknowledgements
Thanks are due to CICECO for the support and to the Portuguese Foundation for Science and Technology for the fellowship grants of S. Pina (FRH/BPD/64119/2009) and A. F. Lemos (SFRH/BPD/27046/2006), and to Romanian Ministry of Education and Research for the financial support of Core Program-Contract PN09-45 and ID 76 scientific projects. Authors are grateful to Cristian-Mihail Teodorescu for the professional assistance with XPS measurements.