Alqarni Nawal D, Wysocka Joanna, El-Bagoury Nader, Ryl Jacek, Amin Mohammed A, Boukherroub Rabah
Materials Science and Engineering Group, Department of Chemistry, Faculty of Science, Taif University 888 Hawiya Saudi Arabia
Department of Electrochemistry, Corrosion and Materials Engineering, Chemical Faculty, Gdansk University of Technology Narutowicza 11/12 80-233 Gdansk Poland.
RSC Adv. 2018 May 24;8(34):19289-19300. doi: 10.1039/c8ra02031k. eCollection 2018 May 22.
The electrochemical and corrosion (uniform and localized) behavior of a binary NiTi shape memory alloy (SMA) and two ternary NiTi Co ( = 1.5 and 4.0 wt%) SMAs were studied. Measurements were conducted in 0.9% NaCl solution at 37 °C employing various electrochemical methods. These include: linear polarization resistance (LPR), linear sweep voltammetry (LSV), chronoamperometry and dynamic electrochemical impedance spectroscopy (DEIS). Such measurements were complemented with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. Results revealed that the addition of alloyed Co to NiTi significantly reduced the uniform corrosion rate of the studied SMA and greatly enhanced its pitting corrosion resistance. XPS measurements evidenced high stability of the passive layer and limited adsorption of chloride ions. Additionally, it was found that the passive layer remained primarily composed of titanium oxides. Microstructure changes accompanying the addition of Co were also used to account for its role in improving the corrosion resistance of these materials.
研究了二元镍钛形状记忆合金（SMA）以及两种三元镍钛钴（钴含量分别为1.5 wt%和4.0 wt%）形状记忆合金的电化学和腐蚀（均匀腐蚀和局部腐蚀）行为。在37℃的0.9%氯化钠溶液中采用多种电化学方法进行测量。这些方法包括：线性极化电阻（LPR）、线性扫描伏安法（LSV）、计时电流法和动态电化学阻抗谱（DEIS）。这些测量辅以扫描电子显微镜（SEM）和X射线光电子能谱（XPS）分析。结果表明，向镍钛合金中添加钴显著降低了所研究形状记忆合金的均匀腐蚀速率，并大大提高了其点蚀抗性。XPS测量证明了钝化膜的高稳定性以及氯离子的有限吸附。此外，还发现钝化膜主要由钛氧化物组成。添加钴伴随的微观结构变化也被用来解释其在提高这些材料耐腐蚀性方面的作用。
