Tropical soil may corrode underground pipelines. X70 pipelines are exposed to peat, organic clay, and sedentary soil within 15 days under ex-situ conditions for surface corrosion study. X-ray Fluorescence (XRF) analysis showed that Fe2O3, SiO2, and Al2O3 dominated the soil bulk. X-ray Diffraction (XRD), Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDX), Laser Raman Spectroscopy, and X-ray Photoelectron Spectroscopy (XPS) were employed for the chemical and physical characterization of soil particles and corrosion products. SEM-EDX revealed that the morphology of the corrosion products exhibited a combination of heterogeneous and fractured surfaces. XRD, Laser Raman, and XPS analyses confirmed that the corrosion products are predominantly composed of Fe2O3 and Fe3O4 compounds. The corrosion rate of 0.18 mm/year in peat soil is notably higher than that observed in other soil types. In conclusion, this study confirms that tropical soils cause X70 pipeline corrosion products predominantly to consist of Fe2O3 and Fe3O4.
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