Preliminary Study of Melastoma Malabathricum L. Leaf Extract as a Green Corrosion Inhibitor for Car Radiator

Abstract

Corrosion in automotive cooling systems is a persistent issue that compromises efficiency and component lifespan. Synthetic corrosion inhibitors commonly used in radiator coolants help mitigate corrosion but have raised environmental concerns due to their toxic byproducts. This study evaluates tannin extracted from Melastoma Malabathricum L. leaves as a natural, eco-friendly corrosion inhibitor. Tannin was extracted using the solvent extraction method and characterised by XRD and FTIR. The corrosion resistance of aluminium substrates in car radiators was tested in various mediums (HCl, NaOH, deionised water, and radiator coolant) over 24, 48, and 72 hours using the weight loss measurement (WLM) method. Results revealed significant corrosion rate and inhibition efficiency, particularly in NaOH, supported by reduced weight loss and improved microstructural stability. These findings highlight tannin's potential as a sustainable alternative to synthetic corrosion inhibitors.