Corrosion Resistance In Physiological Solution Research Articles

Corrosion behaviour of the titanium beta alloy nanotubular surface in the presence of fluoride ions

Abstract The titanium bioactivity could be increased by surface nanostructuring. Titanium alloys are using for dental implants manufacturing. It represents a specific problem because of using of the dental treatments with high concentration of fluoride ions and with acidic pH. The corrosion resistance of nanostructured surface of titanium beta alloy in environments with fluoride ions was examined by common electrochemical technique. The electrochemical impedance measurement showed high corrosion resistance in physiological solution. The fluoride ions have expected negative influence on corrosion behaviour of the layer. The nanotube bottom was preferentially attacked which resulted in layer undercoroding and its detachment.

In vitro corrosion behavior and biocompatibility of nanostructured Ti6Al4V

Ti6Al4V (TC4) alloy has long been used as a bone interfacing implant material in dentistry and orthopedics due to its excellent biocompatibility and mechanical properties. The performance of TC4 can be further tailored by altering its grain structures. In this study, by means of sliding friction treatment (SFT), a nano-grained (NG) surface layer with an average grain size of ≤100 nm on the topmost surface was successfully generated on coarse-grained (CG) TC4 alloy sheet. It was shown that the NG surface possessed notably enhanced corrosion resistance in physiological solution compared to the CG surface, due to the formation of thicker and denser passive film facilitated by surface nanocrystallization. Additionally, the NG surface with stronger hydrophilicity favorably altered the absorption of anchoring proteins such as fibronectin (Fn) and vitronectin (Vn) that can mediate subsequent osteoblast functions. The in vitro results indicated that the NG surface exhibited remarkable enhancement in osteoblast adherence, spreading and proliferation, and obviously accelerated the osteoblast differentiation as compared to CG surface. Moreover, the NG surface also demonstrated good hemocompatibility. These findings suggest that SFT can endure bio-metals with advanced multifunctional properties for biomedical applications.

Electrochemical Corrosion Behavior of Ti-6Al-4V Alloy Using Akermanite As a Bioceramic Coating

In recent years, ceramic material Akermanite (Ca2­Mg­Si2O7) by the ability to connective and link with the hard tissue of the body, In the recovery, treatment and orthopedics of bone and implants coated body has been considered. The purpose of this research was manufacture, preparation and evaluation and characterized of Akermanite nanoparticles and applied this coating on titanium alloy substrate (Ti-6Al-4V) with sol-gel method. Akermanite nanoparticles were prepared by sol-gel method and its structure was determined by X-ray diffraction test. To study the morphology and particle size of Akermanite, transmission electron microscopy (TEM) was used. The morphology and microstructure surface of coating were evaluated by scanning electron microscopy (SEM). Bioactivity of coating was evaluated in body simulation solutions (SBF). Polarization and electrochemical impedance electrochemical test in two different physiological solution was performed in order to compare the corrosion behavior of coated and uncoated titanium samples. Transmission electron microscopy was confirmed powder sizes below 100­nm. According to the Tofel and Linear polarization tests, in the presence of coating in physiological solution compared to Ringer's solution, corrosion current density decreased and corrosion potential shifted to the more noble values and corrosion resistance of the alloy increased. Based on the results obtained by the impedance test, in the presence of Akermanite coating in physiological solution, charge transfer resistance increased and double-layer capacity decreased, which shows improvement in corrosion resistance. According to the corrosion tests, Akermanite coating created on the surface of titanium alloy, has created higher corrosion resistance in physiological solution, compared to Ringer's solution. According to the results of bioactivity test and scanning electron microscopy (SEM), hydroxyapatite is formed on the surface of alloy. The results showed that Akermanite bioceramic coating applied by the sol-gel method, reduced the release of metal ions and improve the biocompatibility of metal implants and also, promote their potential ability to the growth of bone and connective with it.

Structure and corrosion resistance in physiological solution of Hf–Si–N films deposited by IBAD

In this paper, Hf–Si–N films were deposited on AZ31 magnesium alloys by ion beam assisted deposition (IBAD) technology. The phase structure, chemical valence state and nano-mechanical property of the films were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nano-indentation test, respectively. The corrosion resistance in physiological solution was studied by electrochemical system. The results show that the main phases of the films are HfN phase and Si3N4 phase. And the films have good corrosion resistance in physiological solution.