利用飞行时二次离子质谱法成像金属颜料界面的腐蚀
Summary
与暴露在空气中的试样相比, 采用飞行时间二次离子质谱法, 在铝合金的金属漆界面上进行化学映射和腐蚀形态。
Abstract
利用飞行时间二次离子质谱 (ToF-SIMS) 对铝合金的漆和铝 (铝) 金属漆界面的腐蚀进行了分析, 说明 SIMS 是研究铝合金化学分布的一种合适技术。金属油漆界面。涂装的铝合金优惠券浸入盐溶液中或只暴露在空气中。SIMS 提供界面的化学映射和二维分子成像, 允许直接显示在金属漆界面形成的腐蚀产物的形态, 并在腐蚀发生后对化学进行映射。介绍了该方法的实验过程, 以提供技术细节, 便利类似的研究, 并突出此类实验中可能遇到的陷阱。
Introduction
铝合金由于其高强度重量比、出色的成形性和耐腐蚀性, 在工程结构中有着广泛的应用, 如海洋技术或军用汽车。然而, 铝合金的局部腐蚀仍然是一种普遍现象, 影响着铝合金在各种环境条件下的长期可靠性、耐久性和完整性1。涂料是最常见的防腐蚀手段。在金属和油漆涂层之间的界面上形成的腐蚀说明可以为确定防止腐蚀的适当补救措施提供见解。
铝合金的腐蚀可能通过几种不同的途径发生。X 射线光电子能谱 (XPS) 和扫描电子显微镜/色散 x 射线光谱 (semsedx) 是研究腐蚀的两种常用表面显微分析技术。Xps 可以提供元素映射, 但不能提供表面化学信息2,3的全息分子视图, 而 semsedx 提供形态信息和元素映射, 但灵敏度相对较低。
ToF-SIMS 是另一种具有较高质量精度和横向分辨率的化学制图表面工具。它具有较低的检测极限 (LOD), 能够揭示在金属漆界面形成的腐蚀物种的分布。通常情况下, SIMS 质量分辨率可以达到 5000-15000, 足以区分等压离子4。ToF-SIMS 具有亚微米空间分辨率, 可以对金属涂料界面进行化学成像和表征。它不仅提供了形态信息, 而且还提供了分子腐蚀物种在表面前几纳米的横向分布。ToF-SIMS 为 XPS 和 SIM/EDX 提供补充信息。
为了证明 ToF-SIMS 在腐蚀界面的表面表征和成像方面的能力, 分析了两个涂装铝合金 (7075) 优惠券, 一张只暴露在空气中, 一张暴露在盐溶液中 (图 1和图 2)。例如, 了解暴露在盐水条件下的金属漆界面的腐蚀行为对于了解铝合金在海洋环境中的性能至关重要。众所周知, 铝 (OH)3的形成发生在铝暴露于海水5,但铝腐蚀的研究仍然缺乏全面的分子鉴定的腐蚀和涂层界面。在这项研究中, 观察和识别了铝 (oh)3的碎片, 包括铝氧化物(例如, 铝 3o5-) 和氢氧化氧物 (例如, 铝 3o6 h2–).对负离子铝 3 o5 和铝3o6h2 的 sims 质谱 (图 3)和分子 图像(图 4) 的比较提供了分子在盐溶处理铝合金优惠券的金属漆界面形成的腐蚀产物的证据。SIMS 为阐明金属漆界面上发生的复杂化学提供了可能性, 有助于揭示铝合金表面处理的有效性。在这个详细的协议中, 我们演示了这种有效的方法, 用于探测金属油漆界面, 以帮助使用 ToF-SIMS 进行腐蚀研究的新实践者。
Protocol
Representative Results
Discussion
ToF-SIMS 根据离子在两个闪烁器之间的飞行时间来区分离子。地形或样品粗糙度会影响来自不同起始位置的离子的飞行时间, 这通常会导致质量分辨率低, 峰宽度增加。因此, 重要的是要被分析的 Roi 是非常平坦的, 以确保良好的信号收集8。
另一个需要避免的陷阱是充电。由于铝漆界面与绝缘树脂固定, 预计充电。当 ROI 被主离子束轰炸时, 电荷会在样品表面积聚…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
这项工作得到了太平洋西北国家实验室 (PNL) 支持的快速启动方案的资助。PNNL 由 Battelle 为美国能源部运营。这项工作是利用位于 PNNL 生物科学设施内的 TOF-SIMS V 进行的。JY 和 X-Y yu 还感谢 NNL 大气科学 & 全球变化司以及物理和计算科学局 (PCSD) 的支持。
Materials
| 0.05 µm Colloidal Silica polishing Solution | LECO | 812-121-300 | Final polishing solution |
| 1 µm polishing solution | Pace Technologies | PC-1001-GLB | Water based polishing solution |
| 15 µm polishing solution | Pace Technologies | PC-1015-GLBR | Water based polishing solution |
| 3 µm polishing solution | Pace Technologies | PC-1003-GLG | Water based polishing solution |
| 6 µm polishing solution | Pace Technologies | PC-1006-GLY | Water based polishing solution |
| Balance | Mettler Toledo | 11106015 | It is used for measuring the chemicals. |
| Epothin 2 epoxy hardener | Buehler | 20-3442-064 | Used for casting sample mounts |
| Epothin 2 epoxy resin | Buehler | 20-3440-128 | Used for casting sample mounts |
| Fast protein liquid chromatography (FPLC) conductivity sensor | Amersham | AKTA FPLC | Used to measure the conductivity of the salt solution. |
| Final B pad | Allied | 90-150-235 | Used for 1 µm and 0.05 µm polishing steps |
| KCl | Sigma-Aldrich | P9333 | Used to make the salt solution. |
| Low speed saw | Buehler Isomet | 11-1280-160 | Used to cut the Al coupons that are fixed in the epoxy resin. |
| MgCl2 | Sigma-Aldrich | 63042 | Used to make the salt solution. |
| MgSO4 | Sigma-Aldrich | M7506 | It is used to make the salt solution. |
| NaCl | Sigma-Aldrich | S7653 | It is used to make the salt solution. |
| NaOH | Sigma-Aldrich | 306576 | It is used for adjusting pH of the salt solution. |
| Paint | Rust-Oleum | 245217 | Universal General Purpose Gloss Black Hammered Spray Paint. It is used to spray on the Al coupons. |
| Pan-W polishing pad | LECO | 809-505 | Used for 15, 6, and 3 µm polishing steps |
| pH meter | Fisher Scientific | 13-636-AP72 | It is used for measuring the pH of the salt solution. |
| Pipette | Thermo Fisher | Scientific | Range: 10 to 1,000 µL |
| Pipette tip 1 | Neptune | 2112.96.BS | 1,000 µL |
| Pipette tip 2 | Rainin | 17001865 | 20 µL |
| Silicon carbide paper | LECO | 810-251-PRM | Grinding paper, 240 grit |
| Sputter coater | Cressington | 108 sputter coater | It is used for coating the sample. |
| Tegramin-30 Semi-automatic polisher | Struers | 6036127 | Coarse/fine polishing/grinding |
| ToF-SIMS | IONTOF GmbH, Münster, Germany | ToF-SIMS V, equipped with Bi liquid metal ion gun and flood gun | It is used to acquire mass spectra and images of a specimen. |
| Vibromet 2 vibratory polisher | Buehler | 67-1635-160 | Final polishing step |
Riferimenti
- Szklarska-Smialowska, Z. Pitting corrosion of aluminum. Corrosion Science. 41, 1743-1767 (1999).
- Liu, M., et al. A first quantitative XPS study of the surface films formed, by exposure to water on Mg and on the Mg-Al intermetallics: Al3Mg2 and Mg17Al12. Corrosion Science. 51 (5), 1115-1127 (2009).
- Linford, M. R. An introduction to time-of-flight secondary ion mass spectrometry (ToF-SIMS). Vacuum Technology & Coating. , (2014).
- Cushman, C., et al. A pictorial view of LEIS and ToF-SIMS instrumentation. Vacuum Technology & Coating. , 27-35 (2016).
- Soler, L., et al. Hydrogen generation by aluminum corrosion in seawater promoted by suspensions of aluminum hydroxide. International Journal of Hydrogen Energy. 34 (20), 8511-8518 (2009).
- Ahmad, Z., Abdul Aleem, B. J. Degradation of aluminum metal matrix composites in salt water and its control. Materials & Design. 23 (2), 173-180 (2002).
- Verdier, S., Metson, J. B., Dunlop, H. M. Static SIMS studies of the oxides and hydroxides of aluminium. Journal of Mass Spectrometry. 42 (1), 11-19 (2007).
- Esmaily, M., et al. A ToF-SIMS investigation of the corrosion behavior of Mg alloy AM50 in atmospheric environments. Applied Surface Science. 360, 98-106 (2016).
- Hunt, C. P., Stoddart, C. T. H., Seah, M. P. The surface analysis of insulators by SIMS: Charge neutralization and stabilization of the surface potential. Surface and Interface Analysis. 3 (4), 157-160 (1981).
- Stingeder, G. Quantitative distribution analysis of B, As and Sb in the layer system SiO2/Si with SIMS: elimination of matrix and charging effects. Fresenius’ Zeitschrift für analytische Chemie. 327 (2), 225-232 (1987).
- Cushman, C., et al. Sample Charging in ToF-SIMS: How it Affects the Data that are Collected and How to Reduce it. Vacuum Technology & Coating. , (2018).
- Dubey, M., Brison, J., Grainger, D. W., Castner, D. G. Comparison of Bi(1), Bi(3) and C(60) primary ion sources for ToF-SIMS imaging of patterned protein samples. Surface and Interface Analysis: SIA. 43 (1-2), 261-264 (2011).
- Kozole, J., Winograd, N., Smentkowski, V. S. Cluster Secondary Ion Mass Spectrometry. Surface Analysis and Techniques in Biology. , 71-98 (2014).
- Tyler, B. J., Rayal, G., Castner, D. G. Multivariate analysis strategies for processing ToF-SIMS images of biomaterials. Biomaterials. 28 (15), 2412-2423 (2007).
- Song, W., et al. Corrosion behaviour of extruded AM30 magnesium alloy under salt-spray and immersion environments. Corrosion Science. 78, 353-368 (2014).
- Esmaily, M., et al. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium. Ultramicroscopy. 153, 45-54 (2015).
- Liao, J., Hotta, M., Motoda, S. -. i., Shinohara, T. Atmospheric corrosion of two field-exposed AZ31B magnesium alloys with different grain size. Corrosion Science. 71, 53-61 (2013).
- deVries, J. E. Surface characterization methods- XPS,TOF-SIMS, and SAM a complimentary ensemble of tools. Journal of Materials Engineering and Performance. 7 (3), 303-311 (1998).
- Zhang, H., Cooper, S. L., Guan, J. Surface characterization techniques for polyurethane biomaterials. Advances in Polyurethane Biomaterials. , 23-73 (2016).
