Replacing tin Coatings with Chromium Oxide Nanocomposites to Improve the Inner Lining of Low Carbon Steel Food Cans

Document Type : Original Article

Authors

1 Department of Metallurgy Engineering, College of Production Engineering and Metallurgy, University of Technology, P.O. Box: 10066, Baghdad, Iraq

2 Department of Science, Al-Turath University, P.O. Box: 10001, Baghdad, Iraq

3 Iraqi Corrosion Center, Cooperation of Research and Industrial Development, Ministry of Industry and Minerals, P.O. Box: 10100, Baghdad, Iraq

Abstract

In regions with extreme climatic fluctuations-such as Iraq, characterized by high ambient temperatures, variable humidity, and extended food storage periods-the corrosion resistance and structural integrity of metal food packaging present critical challenges. Conventional tin-coated steel cans, though widely adopted, often fail to provide adequate long-term protection against corrosion and mechanical degradation under these harsh environmental conditions. This study proposes an innovative, non-toxic chromium oxide (Cr2O3) nanoparticle-reinforced polymeric coating as a sustainable and effective alternative to conventional tin linings for low-carbon steel food cans. The nanocomposite was formulated by dispersing Cr2O3 nanoparticles (0.1-0.3 wt.%) within a food-grade polymer matrix prepared from locally available Iraqi raw materials. The coatings demonstrated enhanced adhesion strength and corrosion resistance, both of which increased proportionally with nanoparticle content. Quantitatively, coatings with 0.1, 0.2, and 0.3 % Cr2O3 achieved adhesion strengths of 3.3 MPa, 3.8 MPa, and 4.0 MPa, respectively, with corresponding corrosion protection efficiencies of 74, 81, and 89 %. In contrast, traditional 0.3 % Sn-coated samples showed significantly lower performance, with an adhesion strength of 2.2 MPa and corrosion resistance limited to 45 %. Post-cyclic polarization SEM analysis revealed extensive cracking in Sn-based coatings, while Cr2O3 nanocomposites displayed minimal micro-pitting (<2 μm) and a ~70 % reduction in crack density. Tafel extrapolation confirmed the superior stability of Cr2O3 coatings, sustaining performance up to 1950 mV without significant degradation. The study validates that Cr2O3 nanocomposites not only surpass tin coatings in mechanical robustness and corrosion inhibition but also offer an eco-friendly, scalable solution for food packaging. Leachate bio-compatibility tests further affirm their suitability for food-contact applications, making them particularly suitable for use in climates similar to Iraq's.

Keywords

Main Subjects

References

  1. Smith JA, Wilson RK, Chen L, Kumar S. Environmental impact assessment of food packaging materials in extreme climatic conditions. J Food Eng. 2023; 295:110456. https://doi.org/10.1016/j.spc. 2024. 06.032.
  2. Zhang Y, Liu P, Wang H, Li M. Enhanced corrosion resistance of polymer coatings reinforced with Cr2O3 nanoparticles for food packaging applications. Corros Sci. 2022;195:109865. https://doi.org/10.1016/j. inoche. 2025.114411.
  3. Ahmed S, Rahman M, Ali K, Hussein A. Nano-structured Cr2O3-based polymer coatings for improved adhesion and corrosion protection. Prog Org 
    Coat. 2021; 150:105961. https://doi.org/10.1016/j. inoche. 2025. 114411.
  4. Kumar R, Singh A, Patel N, Sharma V. Role of chromium oxide nanoparticles in enhancing barrier properties of food-contact polymer coatings. J Mater Chem A. 2020;8(36):18762-72. https://doi.org/10. 1039/ d4ra03711a
  5. Al-Hashemi SA, Mohammad AA, Al-Rubaiey SI. Nationwide survey of food can deterioration in Iraqi markets under local climatic conditions. Iraqi J Eng Technol. 2023;21(4):45-58.
  6. Martinez AL, Rodriguez C, Gonzalez F, Lopez M. High-temperature corrosion behavior of tin and chromium oxide coatings in arid environments. J Electrochem Soc. 2023; 170(3):031506.
  7. Lee CH, Kim HJ, Park SY, Choi DH. Electrochemical and morphological characterization of protective coatings for food cans. Surf Coat Technol. 2022;445:128734. https://doi.org/10.1016/j.electacta. 2022.140652.
  8. Wang X, Thompson B, Davis R, Johnson M. Galvanic corrosion in tin-plated steel food cans: morphological insights. ElectrochimActa. 2024; 443:141243.
  9. Li J, Wang H, Zhou X, Yang Q. Structural and electrochemical properties of chromium oxide nanocomposite coatings on steel substrates. Surf Coat Technol. 2023; 456:129978. https://doi.org/10.1016/j. surfcoat.2007.05.041.
  10. ASTM D645-97(2017). Standard Test Method for Thickness of Paper. ASTM International; 2017. 

Files

Share

How to cite

Statistics