Bio-corrosion behavior and mechanical characteristics of magnesium-titania-hydroxyapatite nanocomposites coated by magnesium-oxide flakes and silicon for use as resorbable bone fixation material

This study was aimed to improve of the corrosion resistance and mechanical properties of Mg/15TiO2/5HA nanocomposite by silicon and magnesium oxide coatings prepared using a powder metallurgy method. The phase evolution, chemical composition, microstructure and mechanical properties of uncoated and coated samples were characterized. Electrochemical and immersion tests used to investigate the in vitro corrosion behavior of the fabricated samples. The adhesion strength of ~36 MPa for MgO and ~32 MPa for Si/MgO coatings to substrate was measured by adhesion test. Fabrication a homogenous double layer coating with uniform thicknesses consisting micro-sized particles of Si as outer layer and flake-like particles of MgO as the inner layer on the surface of Mg/15TiO2/5HA nanocomposite caused the corrosion resistance and ductility increased whereas the ultimate compressive stress decreased. However, after immersion in SBF solution, Si/MgO-coated sample indicates the best mechanical properties compared to those of the uncoated and MgO-coated samples. The increase of cell viability percentage of the normal human osteoblast (NHOst) cells indicates the improvement in biocompatibility of Mg/15TiO2/5HA nanocomposite by Si/MgO coating

In�vitro biodegradation, electrochemical corrosion evaluations and mechanical properties of an Mg/HA/TiO2nanocomposite for biomedical applications

In this study, a biodegradable Mg/HA/TiO2nanocomposite was prepared using a milling-pressing-sintering powder metallurgy technique. The combined effects of hydroxyapatite (HA) and titania (TiO2) on the corrosion behavior of pure Mg were investigated via in�vitro immersion and electrochemical tests in a simulated body fluid (SBF), and changes in the mechanical properties were analyzed using a compression test. Furthermore, X-ray diffraction, Fourier-transform infrared spectroscopy, atomic-force microscopy, field-emission scanning electron microscopy and transmission electron microscopy were used to investigate the composition and microstructure of the Mg/HA/TiO2bionanocomposite as well as the morphology of the corrosion products. The corrosion rate of the Mg/HA nanocomposite decreased both in terms of mass loss and hydrogen evolution with a decrease in HA from 27.5 to 5�wt% and an addition of 15�wt% TiO2. By sintering the Mg/HA/TiO2nanocomposites, MgTiO3nanoflakes were formed with a hierarchical microstructure on the surface of the samples. The compression and electrochemical tests indicated that the ternary Mg/12.5HA/10TiO2nanocomposite had a good combination of mechanical properties and corrosion resistance of 12.17�k�cm2in the SBF solution. The cell culture results indicated that the Mg/HA/TiO2nanocomposite was biocompatible with osteoblasts

The role of titania on the microstructure, biocorrosion and mechanical properties of Mg/HA-based nanocomposites for potential application in bone repair

Bone defects are very challenging in orthopedic practice. The ideal bone grafts should provide mechanical support and enhance the bone healing. Biodegradable magnesium (Mg)–based alloys demonstrate good biocompatibility and osteoconductive properties, which are promising biomaterials for bone substitutes. However, the high rate of their biodegradation in human body environment is still challenging. For this scope, synthesis Mg-based composites with bioceramic additives such as HA and titania (TiO2) is a routine to solve this problem. The aim of this study was to evaluate the effect of addition TiO2 nanopowders on the corrosion behavior and mechanical properties of Mg/HA-based nanocomposites fabricated using a milling-pressing-sintering technique for medical applications. The microstructure of Mg/HA/TiO2 nanocomposites, in vitro degradation and biological properties including in vitro cytocompatibility were investigated. The corrosion resistance of Mg/HA-based nanocomposites was significantly improved by addition 15 wt% of TiO2 and decrease HA amount to 5 wt% this was inferred from the lower corrosion current; 4.8 µA/cm2 versus 285.3 µA/cm2 for the Mg/27.5 wt%HA, the higher corrosion potential; −1255.7 versus −1487.3 mVSCE, the larger polarization resistance; 11.86 versus 0.25 kΩ cm2 and the significantly lower corrosion rate; 0.1 versus 4.28 mm/yr. Compressive failure strain significantly increased from 1.7% in Mg/27.5HA to 8.1% in Mg/5HA/15TiO2 (wt%). The Mg/5HA/15TiO2 (wt%) nanocomposite possessed high corrosion resistance, cytocompatibility and mechanical properties and can be considered as a promising material for implant applications