Delhi iron pillar rust characterization by fourier transform infrared spectroscopy analysis

The oldest rust from the Delhi iron pillar was characterized by Fourier transform infrared spectroscopy (FTIR). The constituents of the scale were -, -, -FeOOH, Fe3-xO4 and phosphate. The FTIR results also revealed that the scale was hydrated. The unambiguous identification of the iron oxides/oxyhydroxides in the FTIR spectrum implies that they are present in the amorphous state as x-ray diffraction (XRD) analysis did not reveal these phases. The results of the present study are compared with earlier FTIR spectroscopic results of atmospheric rust formation.