Effect of Cu2+ on Corrosion Behavior of A106B Carbon Steel and 304L Stainless Steels in Seawater

The corrosion behaviors of A106B carbon steel and 304L stainless steel (SS) in seawater with different Cu2+ concentrations were studied by the immersion test and the potentiodynamic polarization test. The results showed that with the increasing Cu2+ concentration, the mass lot rates of A106B and 304L SS all increased in the immersion test, and compared with A106B, the mass lot rates of 304L SS were all smaller. In the potentiodynamic polarization test, following the concentration of Cu2+ increased, the corrosion potential of A106B firstly shifted negatively; then, when Cu2+ increased to 100 ppm, the polarization curve moved to the upper right direction; namely, both the corrosion potential and corrosion electrical density increased. The corrosion potential of 304L SS increased with the increasing Cu2+, and the passive region was reduced; the pitting sensitivity improved.

Electrochemical Analysis of Nano- and Micro-Sized Pore Formed Ti–6Al–4V Alloys in Solution Containing Ca, P, Mn, and Si Ions via Plasma Eletrolytic Oxidation for Bio-Implant Materials

The purpose of this study was to investigate electrochemical analysis of nano- and micro-sized pore formed Ti–6Al–4V alloys in solution containing Ca, P, Mn and Si ions via plasma eletrolytic oxidation for bio-implant materials. The coatings were produced on Ti–6Al–4V alloy for dental implant using the plasma electrolytic oxidation (PEO) method in electrolytes with the various concentration of 0, 5, and 20% Mn and Si, respectively. Electrochemical potentiodynamic polarization and AC impedance behaviors were carried out in 0.9% NaCl solution at 36.5 ± 1 °C using potentiostat (Potentiostat, EG&G, 362) and electrochemical impedance spectroscope (EIS, EG&G, 1025). The potentiodynamic polarization test with a scan rate of 1.667 mV s-1 was carried out from –1500 mV to 2000 mV. The frequency range used for EIS was 102–105 Hz. The amplitude of AC signal was 10 mV and 5 points per decade was used. From the potentiodynamic polarization test, PEO treated alloy in electrolyte containing Ca, P, Mn, and Si show a lower corrosion potential than that on the bulk surface. In the case of Mn and Si doped surface, the corrosion resistance increase compared to non-doped surface with Mn and Si elements, and the current density was lower than that of the bulk surface. From the AC impedance test, in the case of Mn and Si doped surface, polarization resistance values were higher than other specimens, and nano- and micro-sized pores were covered with corrosion product consisted Mn and Si elements.

Influence of Organic Sealed on the Corrosion Behaviors of Micro Arc Oxidation Coated ZM5 Magnesium Alloy

An attempt was made to produce organic sealed micro arc oxidation coatings on ZM5 magnesium alloy using two different kinds of organic solution which are acrylics and PTFE. The thickness, potentiodynamic polarization test, corrosion weight lost and morphologies of the coatings were investigated. The results indicate that PTFE sealed micro arc oxidation coatings has relatively dense and uniform surface to show the best anti-corrosion performance.

Electrochemical Properties of UFG CP-Ti in Ringer’s Solution

The effect of ECAE pass number on the electrochemical properties of CP-Ti was investigated by electrochemical techniques (potentiodynamic polarization test, potentiodynamic polarization test and surface analyses (OM, scanning electron microscopy (SEM) in Ringer’s solution at 37°C. The results show that the corrosion resistance of muli-pass ECAE CP-Ti samples is superior to the coarse grain CP-Ti. The effect of texture of ECAEed samples parallel to the surface on the corrosion properties has been discussed.