Section 4: Composite artefacts (PDF 20858kb) - National Museum of ...

Proceedings of Metal 2004 National Museum of Australia Canberra ACT 4–8 October 2004ABN 70 592 297 967Figure 2: E corr monitoring for “bare”, “slightly polished” and “corroded” iron nails in 1%(w/v) NaNO 3 solution“Corroded” nails have the higher initial potentials due to the presence of a thick corrosionlayer that passivates the surface. The potentials obtained after five minutes of immersion (0 to-250 mV/SHE, Standard Hydrogen Electrode=0V) and inserted in a simplified Pourbaixdiagram for Fe, confirm that in the present conditions the coupons should corrode (Figure 3).The stabilisation of iron based materials in neutral solution requires cathodic polarization towork.© Published by the National Museum of Australia www.nma.gov.au431