Monitoring complexing agents in galvanic baths inline with Raman spectroscopy

Importance of the topic

Inline monitoring of complexing agents in galvanic baths is critical to maintain consistent quality and efficiency in electroplating processes. Real-time analysis prevents delays and risks associated with laboratory testing and enhances process control.

Objectives and study overview

This application note describes a method for inline determination of organic complexing agents in zinc-nickel galvanic baths. A 2060 Raman Analyzer with a fiber-optic probe and flow cell is deployed to continuously monitor the bath composition under production conditions.

Used methodology and instrumentation

The inline system uses:

• 2060 Raman Analyzer configured for process environments
• Fiber-optic Raman probes and flow cells for direct bath insertion
• Metrohm Vision and IMPACT software for data acquisition and calibration

A robust calibration model is built by correlating Raman spectra with reference laboratory analyses across a representative concentration range of organic additives (0–100 g/L).

Main results and discussion

Inline Raman measurements were compared with manual reference analyses. The inline trend chart demonstrated:

• Accurate tracking of additive concentration changes in real time
• Improved sensitivity to process fluctuations compared to discrete sampling
• Faster response enabling timely corrective actions to maintain bath optimal conditions

Benefits and practical applications

• Real-time feedback ensures tight control of coating characteristics
• Reduction of downtime and safety risks by eliminating manual sampling
• Multiple analytes can be measured simultaneously from a single probe
• Improved consistency and quality of electroplated layers

Future trends and possibilities for application

Future developments may include integration with advanced control algorithms and artificial intelligence for autonomous bath management. The multiplexing capability can extend inline monitoring to multiple baths and additional parameters in surface-finishing industries.

Conclusion

Inline Raman spectroscopy using the 2060 Raman Analyzer provides a rapid, non-destructive approach for quantifying complexing agents in galvanic baths. The method delivers accurate, continuous insights that support enhanced process control, product quality, and operational efficiency.

References

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