Corrosion Resistance of Titanium Alloys Anodized in Alkaline Solutions

Abstract

Titanium alloys present superior electrochemical properties due to the generation of the TiO2 passive layer. The ability to generate an oxide passive layer depends on the anodized alloy. This work mainly studies the corrosion resistance of the alloys Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V anodized in NaOH and KOH at 1 M and 0.025 A/cm2 of current density. The electrochemical techniques were performed in a conventional three-electrode cell exposed to electrolytes of NaCl and H2SO4. Based on ASTM-G61 and G199, cyclic potentiodynamic polarization (CPP) and electrochemical noise (EN) techniques were used. The results indicated that Ti-6Al-2Sn-4Zr-2Mo anodized on NaOH presented a higher passivity range than anodized on KOH, relating to the high reactivity of Na+ ions. The former anodized alloy also demonstrated a higher passive layer rupture potential. In EN, the results showed that Ti-6Al-4V anodized in KOH presented a trend toward a localized process due to the heterogeneity of anodized porosity and the presence of V in the alloy.

Corrosion Behavior of Titanium Alloys (Ti CP2, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-4V and Ti Beta-C) with Anodized and Exposed in NaCl and H2SO4 Solutions

“…The absorption occurs in the porous zones, while the diffusion occurs in the more compact oxide zones. This can create a higher corrosion resistance when the diffuser elements generate another passive layer [54][55][56][57]. The basic chemical reactions that occur in diffusion are:…”

The development of porous metallic materials: a short review of fabrication, characteristics, and applications

“…The application of Titanium porous material is as popular as Aluminum porous material. The remarkable properties of Titanium include high specific strength, corrosion resistance, as well as biocompatibility [84,85]. Thus, the application of Titanium porous material has potential application for implant applications.…”