spark anodizing of CP-titanium and evaluation of its corrosion resistance

Titania porous coating was grown by spark anodizing technique in an alkaline electrolyte containing Na3PO4. The processing time was a few minutes and no post- and pre-treatments were required. Spark anodizing is an electrochemical technique for fabrication of anodic film by sparks which move rapidly on the vicinity of surface substrate. This technique is characterized by high productivity, economic efficiency, ecological friendliness, high hardness, good wear resistance, and excellent bonding strength with the substrate. Especial focus of this study was placed on the improvement of the corrosion resistance of titanium in the de-aerated 40 g/L H2SO4 + 40 g/L NaCl solution at 55 °C. Phase composition and surface morphology of the coated sample were evaluated by XRD and SEM respectively. Obtained results show that Titania porous coating contains Anantase. Corrosion behaviour of sample was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Applying spark Anodizing technique, the corrosion resistance was enhanced successfully and corrosion rate was decreased dramatically from ~2744 μm/year to ~2.22 μm/year

Keywords:

Titanium , Spark Anodizing , Corrosion resistance