E. Aghaie

Electrochemical and cellular behavior of ultrafine-grained titanium in vitro

The electrochemical and cellular behavior of commercially pure titanium (CP-Ti) with both ultrafine-grained (UFG) and coarse-grained (CG) microstructure was evaluated in this study. Equal channel angular pressing was used to produce the UFG structure titanium. Polarization and electrochemical impedance tests were carried out in a simulated body fluid (SBF) at 37°C. Cellular behaviors of samples were assessed using fibroblast cells. Results of the investigations illustrate the improvement of both corrosion and biological behavior of UFG CP-Ti in comparison with the CG counterpart.

Effect of SiC concentration in electrolyte on Ni-SiC composite coating properties

Abstract In the present study, a nickel sulphate bath containing SiC particles between 0·5 and 5·0 μm has been used as the plating electrolyte to obtain Ni–SiC composites on copper surfaces with high hardness and wear resistance for using in antiwear applications such as dies, tools and working parts of automobiles. The influence of SiC concentration in the electrolyte on morphology, microhardness, friction coefficient and wear missing volume of coatings has been studied. The coatings were analysed with scanning electron microscopy as well as X-ray diffraction. The findings indicate that increasing the concentration of SiC particles in the Watts bath results in improving the microhardness of coatings and also decreasing the friction coefficient and wear missing volume. Increasing the presence of SiC particles not only decreases the grain size of Ni crystals but also changes the morphology and preference orientation of Ni crystals.

Effect of Equal Channel Angular Pressing Process on the Corrosion Behavior of Type 316L Stainless Steel in Ringer's Solution

The corrosion behavior of metallic biomaterials is an important characteristic because of its strong relationship to the biocompatibility of biomedical grade metallic implants. The goal of this research was to study the effect of the equal channel angular pressing (ECAP) process on the corrosion behavior of the AISI Type 316L (UNS S31603) austenitic stainless steel. Up to eight passes of ECAP were performed on AISI 316L stainless steel samples. A scanning transmission electron microscopy technique was utilized to study the microstructure of the as-received material and the samples subjected to ECAP. Electrochemical corrosion polarization and electrochemical impedance spectroscopy tests were performed in Ringers solution to determine and compare the corrosion behavior of initial coarse-grained and ECAP specimens as an indication of biocompatibility. An ultrafine-grained nanocrystalline Type 316L stainless steel with a mean grain size of about 78 nm was obtained after eight passes of ECAP were performed. T...

Effect of Tricalcium Magnesium Silicate Coating on the Electrochemical and Biological Behavior of Ti-6Al-4V Alloys

In the current study, a sol-gel-synthesized tricalcium magnesium silicate powder was coated on Ti-6Al-4V alloys using plasma spray method. Composition of feed powder was evaluated by X-ray diffraction technique before and after the coating process. Scanning electron microscopy and atomic force microscopy were used to study the morphology of coated substrates. The corrosion behaviors of bare and coated Ti-6Al-4V alloys were examined using potentiodynamic polarization test and electrochemical impedance spectroscopy in stimulated body fluids. Moreover, bare and coated Ti-6Al-4V alloys were characterized in vitro by culturing osteoblast and mesenchymal stem cells for several days. Results demonstrated a meaningful improvement in the corrosion resistance of Ti-6Al-4V alloys coated with tricalcium magnesium silicate compared with the bare counterparts, by showing a decrease in corrosion current density from 1.84 μA/cm2 to 0.31 μA/cm2. Furthermore, the coating substantially improved the bioactivity of Ti-6Al-4Valloys. Our study on corrosion behavior and biological response of Ti-6Al-4V alloy coated by tricalcium magnesium silicate proved that the coating has considerably enhanced safety and applicability of Ti-6Al-4V alloys, suggesting its potential use in permanent implants and artificial joints.