A Study of Natural Coatings as Corrosion Inhibitors for Metal Surfaces

Abstract

This study investigates the effectiveness of natural coatings derived from turmeric, ginger, aloe vera, and curry leaves, individually mixed with carboxymethyl cellulose (CMC) as a binding agent, in reducing corrosion on metal surfaces. The coated metal samples were air-dried and exposed to hydrochloric acid (HCl) to analyse their corrosion resistance properties. The observations, including weight loss measurements and visual inspections, demonstrate the efficiency of these natural inhibitors. The findings contribute to the development of sustainable and environmentally friendly corrosion prevention techniques.

Introduction

Corrosion significantly affects metal structures in industrial settings, causing material degradation and financial losses. Traditional chemical inhibitors are often toxic and harmful to the environment. This study explores the use of natural plant-based coatings—including turmeric, ginger, aloe vera, and curry leaves—as green corrosion inhibitors for metal protection.

Key Objectives

1. Evaluate corrosion resistance of natural coatings (turmeric, ginger, aloe vera, curry leaves).

2. Understand protective layer formation on metal surfaces.

3. Compare efficiency of natural and synthetic inhibitors.

4. Analyze the adsorption mechanism of natural extracts.

5. Assess environmental impact and performance.

Materials & Methods

• Materials: Mild steel/copper samples, turmeric, ginger, aloe vera, curry leaves, HCl, carboxymethyl cellulose (CMC).

• Preparation:

  • Plant materials were dried, ground, extracted in water, and mixed with CMC.

  • Metal samples were cleaned, coated with the plant pastes, and exposed to dilute HCl.

• Measurements:

  • Corrosion rate was assessed by weight loss after exposure.

  • Visual inspection confirmed rust resistance.

Results & Observations

• Aloe vera was most effective, followed by ginger, due to the presence of polysaccharides, flavonoids, and antioxidants that form a stable barrier.

• Turmeric and curry leaves also offered some protection but were less effective.

Discussion

• Natural inhibitors work via adsorption on metal surfaces, forming a protective film that reduces corrosion.

• Compared to synthetic inhibitors, plant-based coatings are non-toxic, biodegradable, and environmentally safe.

• The study highlights the potential of green chemistry in corrosion control.

Future Scope

• Further research should explore:

  • Durability of coatings in extreme conditions (e.g., humidity, pollutants).

  • Hybrid coatings combining multiple plant extracts.

  • Advanced surface analysis (AFM, XRD) for molecular-level insights.

• Industrial sectors like marine, automotive, oil & gas, and aerospace could benefit from implementing these sustainable coatings.

• Development of eco-regulations and policies can encourage large-scale adoption.

Industrial & Environmental Impact

• Reduced environmental pollution from harmful chemicals.

• Promotes renewable, cost-effective solutions for corrosion management.

• Supports the shift toward sustainable industrial practices.

Conclusion

The study successfully demonstrated that turmeric, ginger, aloe vera, and curry leaves extracts act as effective green corrosion inhibitors. Their ability to adsorb onto metal surfaces and reduce corrosion rates makes them promising alternatives to synthetic inhibitors. The findings support the implementation of plant-based inhibitors in industrial applications to promote sustainability.

References

[1] https://jfas.info/index.php/JFAS/article/view/1384?utm [2] https://www.researchgate.net/publication/281735529_Turmeric_and ginger_as_green_inhibitors_of_mild_steel_corrosion_in_acidic_me dium

Copyright

Copyright © 2025 Vipra Alur, Falguni Bhavsar, Asmi Palekar, Yugandhara Patil, Mrunal Chaudhari. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.