resumo
Bioglasses (BG) are the inorganic materials exhibiting the highest indices of bioactivity. Their appliance as films for bio-functionalization of metallic implant surfaces has been regarded as an optimal solution for surpassing their limited bulk mechanical properties. This study reports on magnetron sputtering of alkali-free BG thin films by varying the target-to-substrate working distance, which proved to play an important role in determining the films' properties. Post deposition heat-treatments at temperatures slightly above the glass transformation temperature were then applied to induce inter-diffusion processes at the BG/titanium substrate interface and strengthening the bonding as determined by pull-out adherence measurements. The morphological and structural features assessed by SEM-EDS, XRD, and FTIR revealed a good correlation between the formations of inter-metallic titanium silicide phases and the films' bonding strength. The highest mean value of pull-out adherence (60.3 +/- 4.6 MPa), which is adequate even for load-bearing biomedical applications, was recorded for films deposited at a working distance of 35 mm followed by a heat-treatment at 750 degrees C for 2 h in air. The experimental findings are explained on the basis of structural, compositional and thermodynamic considerations. (C) 2013 Elsevier B.V. All rights reserved.
palavras-chave
BIOACTIVE GLASS COATINGS; IN-VITRO BEHAVIOR; THIN-FILMS; MECHANICAL-PROPERTIES; THERMAL-EXPANSION; GRADED COATINGS; SILICATE GLASS; TITANIUM; MICROSTRUCTURE; DEPOSITION
categoria
Chemistry; Materials Science; Physics
autores
Stan, GE; Popa, AC; Galca, AC; Aldica, G; Ferreira, JMF
nossos autores
José Maria da Fonte Ferreira
Professor(a) Jubilado(a)agradecimentos
G.E.S. and A.C.P. are thankful for the financial support from the Romanian National Authority for Scientific Research through the UEFISCDI TE 49/05.10.2011 (TE-0164). The support from CICECO is also acknowledged.