Department of Metallurgy and Materials Science, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Angle Orthod. 2013 Sep;83(5):864-9. doi: 10.2319/091712-740.1. Epub 2013 Feb 28.
To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride.
NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy.
Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium.
There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.
评估氟浓度对镍钛（NiTi）超弹性丝腐蚀行为的影响，并比较生理溶液中添加和不添加氟化物时 NiTi 与β钛合金的耐腐蚀性。
通过电化学阻抗谱和在氯化钠（NaCl 0.15 M）中进行阳极极化研究了 NiTi 的耐腐蚀性，并与β钛进行了比较。评估了在 NaCl（0.15 M）中添加和不添加 0.02、0.04、0.05、0.07 和 0.12 M 氟化钠（NaF）溶液对 NiTi 腐蚀行为的影响。研究了 NiTi 和β钛之间的电偶腐蚀。所有样品均通过扫描电子显微镜进行了表征。
随着 NaF 浓度的增加，极化电阻降低，并且根据 NaF 浓度的不同，NiTi 可能会遭受局部或整体腐蚀。在含有 0.02 M NaF 的 NaCl 溶液中，NiTi 发生局部腐蚀，而β钛合金保持钝化状态。NiTi 和β钛电偶耦合时观察到电流值接近零。
存在氟化物时，NiTi 的耐腐蚀性降低。NiTi 合金的腐蚀行为取决于氟化物浓度。当 NaCl 溶液中添加 0.02 和 0.04 M 的 NaF 时，NiTi 呈现局部腐蚀。当 NaF 浓度增加到 0.05、0.07 和 0.12 M 时，合金呈现全面腐蚀。NiTi 的耐腐蚀性低于β钛。这些合金的电偶耦合不会增加腐蚀速率。
