Monitoring complexing agents in galvanic baths inline with Raman spectroscopy

Importance of Monitoring Complexing Agents in Galvanic Baths

The control of complexing agents in electroplating baths is critical for achieving consistent coating quality, corrosion resistance, and operational safety. Inline monitoring enables real-time insights into bath chemistry, preventing off-spec deposits and reducing waste.

Objectives and Study Overview

This application note demonstrates an inline Raman spectroscopy method for quantifying organic complexing agents in galvanic baths. Using the 2060 Raman Analyzer by Metrohm Process Analytics, the study aims to replace manual sampling and laboratory analysis with continuous, automated measurement for improved process control.

Methodology and Instrumentation

Inline monitoring was implemented by connecting the Raman analyzer to plating baths via fiber-optic probes and a flow cell. A calibration model was developed by correlating Raman spectra with reference laboratory measurements across relevant concentration ranges.

• Analyzer: Metrohm 2060 Raman Analyzer
• Probes: In-situ fiber-optic probe(s)
• Software: Metrohm Vision and IMPACT for data acquisition and model deployment
• Calibration: Multivariate regression against lab reference data

Main Results and Discussion

Continuous inline data captured minute-by-minute fluctuations in organic additive concentration, closely matching reference analyses. The real-time trend chart allowed faster corrective dosing, minimizing bath variability and preventing quality deviations. Inline measurements revealed transient shifts that manual sampling overlooked due to time delays.

Benefits and Practical Applications

• Real-time feedback for immediate bath adjustments
• Reduced reliance on manual sampling and lab turnaround times
• Multiplexing capability: single analyzer connected to multiple baths
• Early detection of bath imbalances and potential faults

Future Trends and Potential Applications

Advances may include integration with predictive analytics and digital twins for automated dosing strategies. Expansion to other plating chemistries (e.g., copper, nickel) and on-line monitoring of additional parameters such as metal ion concentration or pH are anticipated. AI-driven spectral interpretation could further enhance model robustness and fault detection.

Conclusion

Inline Raman spectroscopy with the 2060 Raman Analyzer provides a reliable, non-destructive approach for monitoring complexing agents in galvanic baths. The method improves process control, enhances product quality, and reduces operational costs compared to traditional offline analysis.

References

1. Leiden A., Kölle S., Thiede S. Model-Based Analysis, Control and Dosing of Electroplating Electrolytes. Int. J. Adv. Manuf. Technol. 2020, 111(5), 1751–1766. doi:10.1007/s00170-020-06190-0
2. Gezerman A. O. Effects of Novel Additives for Zinc-Nickel Alloy Plating. Eur. J. Chem. 2019, 10, 118–124. doi:10.5155/eurjchem.10.2.118-124.1834
3. Son B.-K., Choi J.-W., Jeon S.-B. Concentration Influence of Complexing Agent on Electrodeposited Zn-Ni Alloy. Appl. Sci. 2023, 13(13), 7887. doi:10.3390/app13137887