A comparative study on the corrosion behavior of porous and dense NiTi shape memory alloys in NaCl solution

• Published in: Electrochimica acta Vol. 56; no. 18; pp. 6389 - 6396
• Main Authors: Sun, X.T., Kang, Z.X., Zhang, X.L., Jiang, H.J., Guan, R.F., Zhang, X.P.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.07.2011; Elsevier
• Subjects: Alloys; Applied sciences; Corrosion; Corrosion behavior; Corrosion mechanisms; Exact sciences and technology; Interconnectivity; Intermetallics; Metals. Metallurgy; Nickel base alloys; Nickel compounds; Nickel titanides; Porosity; Porous electrode; Porous NiTi alloy; Potential distribution; Shape memory alloys; Titanium compounds; Porous NiTi alloy; Porous electrode; Potential distribution; Interconnectivity; Corrosion behavior; Titanium alloy; Scanning electron microscopy; Porous material; Surface structure; Shape memory alloy; Corrosion; Morphology; Comparative study; Nickel alloy; Binary alloy; Sodium Chlorides; Electrochemical impedance spectroscopy
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2011.05.019

► Corrosion behaviors of porous and dense NiTi alloys were systematically compared. ► Non-uniform potential distribution within porous electrodes aggravates localized corrosion. ► Improvement of pores interconnection can help reduce localized corrosion. ► Corrosion behaviors are dominated by combined action of pore structure characteristics. The corrosion behaviors of porous and dense NiTi shape memory alloys with the same nominal composition were investigated in a 0.9% aqueous NaCl solution using electrochemical methods. The study clarified the role of the porous structure in influencing the corrosion behavior of the porous NiTi alloys, which exhibited porosity values ranging from 35.5% to 63.8%. The results indicated that the porous NiTi alloy was more susceptible to localized corrosion than was the dense NiTi alloy. However, the porous NiTi alloy sample with a higher porosity did not suffer more serious corrosion than the one with a lower porosity. Furthermore, the potential distribution exists on the pore wall of the porous NiTi alloys as a result of current flow within the pore electrolyte. Thus, the role of potential distribution inside the pore and porous structure in the corrosion behavior of the porous NiTi alloys is an important factor.