Archaeometallurgy Community

Review of metal formates on heritage objects

  • 1.  Review of metal formates on heritage objects

    Staff Liaison
    Posted 04-27-2021 18:00
    Members of this community may be interested in the following open access paper. Thanks to Patricia Silvana Carrizo for alerting us about the paper.

    Eggert, G., Fischer, A. The formation of formates: 3a review of metal formates on heritage objects. Herit Sci 9, 26 (2021).

    Metal formates sometimes occur as degradation products on heritage objects due to the use of wood products or other sources of formic acid and formaldehyde. They are often related to alkaline surfaces which transform formaldehyde directly into formate. The dominant role of formate on alkaline surfaces, for example in glass-induced metal corrosion (GIM) or calcium carbonate degradation, was explored in the Stuttgart research on rare heritage corrosion products. This review discusses these findings together with those from the literature: ocurrences of sodium and potassium formate on glass, calcium formate and calcium acetate-formate phases on calcareous materials, magnesium formate on Sorel cement and dolomitic sandstone, lead formate on metal and pigments, cadmium formate on coated objects, as well as various copper and zinc formates on copper alloys. In the latter cases, formates dominate as glass-induced metal corrosion products. The formation of formates constitutes irreversible damage, degrading the material of heritage objects. Therefore, preventive conservation needs to remove all sources of carbonyl pollutants in order to avoid such corrosion.

    Scott Henry
    Senior Content Engineer
    ASM International
    Materials Park OH