Corrosion behavior of newly developed Ti–Ag–Fe dental alloys in neutral saline solution

Electrochemical corrosion behaviour of the studied Ni47.7Ti37.8Nb14.5 (NiTiNb) shape memory alloy was investigated for dental applications. An equiatomic NiTi alloy was used in some tests as reference material. Electrochemical techniques such as anodic potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy (EIS) were employed. Experiments were carried out using artificial saliva. Very low passive current densities were obtained from the anodic polarization curve, indicating a typical passive behaviour for NiTiNb alloy. Over the surface of the NiTiNb alloy uniform corrosion appears, while in case of the NiTi alloy surface pitting corrosion is developed. The role that Nb plays as an alloying element is by increasing the resistance of NiTi alloy to localized corrosion. The EIS results exhibited high impedance values (order of 106 Ω cm2) obtained from medium to low frequencies which are indicative of the formation of a highly stable passive film on NiTiNb alloy in the artificial saliva.

Electrochemical characterization of Ni_47.7Ti_37.8Nb_14.5 shape memory alloy in artificial saliva

Mareci¹,

Chelariu²,

Cailean³

et al. 2011

Effects of the Zr and Mo contents on the electrochemical corrosion behavior of Ti–22Nb alloy

Yang

Zhang

Wei

et al. 2012

Ti–22Nb–xZr and Ti–22Nb–xMo (x = 0, 2, 4, 6, in atom percent) were prepared by an arc melting method. The alloys were solution‐treated at 1073 K for 1.8 ks followed by quenching them into ice water, and the electrochemical corrosion behavior in a 0.9% NaCl solution at 25 °C and neutral pH range of the solution‐treated alloys was evaluated by using electrochemical impedance spectroscopy, polarization curves and an equivalent circuit analysis. It was found that the microstructure of the solution‐treated Ti–22Nb alloy mainly contains β phase with small amount of α″ phase, and the addition of Zr or Mo to a Ti–22Nb alloy is efficient to stabilize the β phase. The resulting impedance parameters and passive current densities indicated that the corrosion resistance of the Ti–22Nb alloy was promoted significantly with the addition of Zr and Mo.

Electrochemical and SEM characterization of NiTi alloy coated with chitosan by PLD technique

Mareci

Cimpoeşu

Popa

2012

The production of a wide variety of biocompatible thin films by laser ablation deposed on the biomaterial substrates does not induce inflammatory response and repulsion by the immunization human body. Anodic potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used for the study of the electrochemical behavior of coated NiTi with chitosan through pulsed laser deposition (PLD) technique. Experiments were carried out using two different electrolytes: physiological 0.9 wt% NaCl solution (PS) and PS þ hydrochloric acid (APS) at 37 AE 1 8C. In addition, scanning electron microscopy was employed to observe the surface morphology after maintaining in both electrolytes. The corrosion resistance was evaluated by means of the corrosion and passive corrosion currents. The electrochemical properties of the coated NiTi sample at the open circuit potential at different immersion time in PS and APS were studied by EIS. Equivalent circuits were used to model EIS data, in order to characterize samples' surface.