Thu Feb 06 11:27:15 UTC 2025: ## IIT Bombay Develops New Technique to Measure Iron Coating Degradation

**Mumbai, February 6, 2025** – Researchers at the Indian Institute of Technology (IIT) Bombay have developed a novel technique to accurately measure the degradation rate of protective coatings on iron, a breakthrough with significant implications for the steel industry. The method, combining hydrogen permeation-based potentiometry (HPP) and electrochemical impedance spectroscopy (EIS), offers a cost-effective way to assess the effectiveness of organic coatings in preventing corrosion.

Corrosion is a major issue for metals, costing the global economy billions annually. The market for corrosion inhibitors alone is valued at $8.93 billion and is projected to grow. Organic coatings, while effective, degrade over time due to oxygen reduction reactions (ORR) that allow water and oxygen to reach the metal. Existing methods for evaluating coating degradation are often cumbersome and expensive.

The IIT Bombay team, led by Professor Vijayshankar Dandapani, has overcome this limitation. Their HPP-EIS technique provides a quantitative measure of the degradation rate at the coating-metal interface. HPP directly measures hydrogen permeation, while EIS provides insights into how this permeation contributes to corrosion. The combined approach offers a clearer picture than either method alone, enabling the assessment of ORR even at inaccessible interfaces.

This research, funded by CEFIPRA and SERB, initially demonstrated the technique’s efficacy using palladium and a model polymer. The current study successfully extended it to iron, a crucial industrial metal, by measuring ORR rates between iron coated with poly-methyl methacrylate (PMMA). The researchers found that higher impedance values correspond to lower corrosion rates.

Professor Dandapani highlighted the technique’s versatility, suggesting applications beyond steel production. It could be used to monitor the degradation of coatings in fuel cells, sensors, and even natural gas pipelines where hydrogen blending is increasing. The HPP-EIS method’s simplicity and cost-effectiveness (requiring only two potentiostats) make it a potentially transformative tool for various industries.

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