Metrohm Hyphenated EC-Raman solutions for corrosion

Significance of the Topic

Corrosion affects the longevity and safety of metals across industries such as energy, transportation and infrastructure. Monitoring corrosion in real time under working conditions helps researchers and engineers understand electrochemical degradation mechanisms and develop better protective strategies. The combination of electrochemical techniques with in situ Raman spectroscopy offers both functional and structural insights into evolving surface films, making it a valuable approach for advanced corrosion research.

Objectives and Scope

This application note introduces two turnkey hyphenated EC‐Raman solutions—the Explorer and the Starter—for corrosion studies. Both packages synchronize an electrochemical workstation with a Raman spectrometer to deliver simultaneous measurements. The goal is to provide corrosion scientists with ready-to-use systems that minimize setup complexity while enabling comprehensive analysis of metal surfaces under electrochemical control.

Methodology and Instrumentation

The core methodology integrates three components:

• An Autolab potentiostat/galvanostat with built‐in Electrochemical Impedance Spectroscopy (EIS) module to impose and monitor potentials, currents and impedance spectra.
• A B&W Tek Raman spectrometer (i-Raman Plus 532H) equipped with a 532 nm laser and fiber-optic probe for high-resolution Raman spectra, enhanced for SERS applications.
• A video microsampling cell that provides optical alignment, sample visualization and option for custom corrosion cells.

This setup allows simultaneous linear sweep voltammetry, impedance measurements, surface‐enhanced Raman spectroscopy and microscopic observation under controlled electrochemical conditions. Measurement synchronization is handled by a trigger cable and coordinated through Metrohm NOVA and BWSpec software.

Instrumentation Used

• Autolab PGSTAT302N: potential ±10 V, compliance ±30 V, current ±2 A, bandwidth 1 MHz, EIS 10 µHz–1 MHz.
• Autolab PGSTAT204: potential ±10 V, compliance ±20 V, current ±400 mA, bandwidth 1 MHz, EIS 10 µHz–1 MHz, portable form factor.
• B&W Tek i-Raman Plus 532H: 532 nm laser (up to 30 mW), cooled CCD detector (–2°C), spectral range 65–3400 cm⁻¹, <3.5 cm⁻¹ resolution.
• BAC151 Raman Video Microsampling System: 20× and 50× objectives, 24 mm Z travel, 75 × 50 mm XY stage, coaxial illumination.
• Trigger cable for electrochemical–Raman synchronization via NOVA software.

Key Results and Discussion

Although this document focuses on instrumentation, the combined EC-Raman approach has demonstrated capability to track the formation and dissolution of corrosion films, detect adsorption of inhibitors or additives on metal surfaces, and resolve localized corrosion processes. Simultaneous EIS and Raman spectra reveal correlations between impedance changes and molecular structure alterations in real time. The video sampling system further aids in correlating optical changes with electrochemical events.

Benefits and Practical Applications

• One‐stop solution: Plug‐and‐play packages eliminate complex wiring or synchronization challenges.
• Modularity: Explorer system can be upgraded with additional modules (noise, low-current amplifier, pH/temperature sensors) as research evolves.
• Portable option: Starter solution offers field-deployable EC-Raman capability for on‐site corrosion monitoring.
• Versatile methods: Supports EIS, LSV, SERS and Raman microscopy in a single platform.

Future Trends and Opportunities

Advances in miniaturized cells and fiber probes will enable in‐field EC-Raman monitoring of large structures. Integration with machine learning for spectral‐electrochemical data fusion will enhance predictive corrosion models. Further development of low-current amplifiers and nanostructured SERS substrates promises higher sensitivity for trace film species.

Conclusion

Metrohm’s hyphenated EC-Raman Explorer and Starter solutions streamline the acquisition of synchronized electrochemical and Raman data for corrosion research. By combining high‐precision potentiostats with state‐of‐the‐art Raman spectroscopy and video microsampling, these systems deliver comprehensive insights into surface processes. Their modularity and ease of use make them ideal for both laboratory and field studies, paving the way for more effective corrosion management strategies.