Six MgAl hydrotalcites (Mg/Al = 2 and 3) were synthesized through the modification of two carbonate hydrotalcites (i.e., Mg(2)AlCO3 and Mg(3)AlCO3) by two amino acids (11aminoundecanoic acid and paminobenzoic acid) and sodium nitrite. They were characterized by means of XRD, FTIR, TG/DSC, and elemental analysis. The ion exchange of the modified hydrotalcites (MHTs) were investigated in alkaline chloride solution and the results showed that ion exchange occurred between free chloride ions and the intercalated inhibitive anions in MHT. The corrosion inhibition of three MHTs (Mg/Al = 2) was evaluated based on the open circuit potential and linear polarization resistance evolution of steel coupons in 0.1 M NaOH solution stepwise enriched with chlorides and the results showed that MHT, in particular, Mg(2)AlpAB exhibited an improved corrosion inhibiting effect in terms of a higher chloride threshold compared to its constituent free inhibitor ions (i.e., pAB). This study confirms the dual protection that MHT, in particular, Mg(2)AlpAB, offers to the steel: capturing chlorides and simultaneously releasing the intercalated inhibitors to further protect the steel from corrosion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim@en

In previous papers, we showed that it is possible to modify the colour of gilding on the silver substrate by applying a surface chemical treatment after it has been burnished [Crabbé et al., Surf. Interface Anal. 2008, 40, 467; Crabbé et al. Applied Physics A, 2013, 111, 39]. These types of techniques are recounted in many medieval and older manuscripts [Crabbé et al., Arch. des Biblio. de Belgique. 2011, 94, 1581]. They have to be taken into account when applying conservation-restoration cleaning to silver gilded statuettes such as the ones from the Holy Lady Shrine from Huy (13th century, Belgium) [Didier et al., Bull. de L'IRPA 1970, 12, 5]. Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM-EDX) and synchrotron X-ray Absorption Spectroscopy (XAS) were carried out both on model and historical samples with the aim of determining if medieval colour treatment has been applied in an efficient way to the silver gilded statuettes of the shrine. Those results are of first importance to the conservator-restorer responsible for the shrine restoration treatment. They will influence the treatment applied to the shrine but also the interpretation of the art-piece, its final aspect and the art-history of medieval times.@en