Temperature- and humidity-induced changes in alum-treated wood: a qualitative X-ray diffraction study

• DOI: 10.1186/s40494-018-0232-z
• Publication Date: 2018-11-23T11:47:56Z
• Authors: Caitlin M. A. McQ...; Calin C. Steindal; Olga Narygina; Susan Braovac
• Keywords: Alum; Efflorescence

Alum-treated wooden artefacts suffer from extreme deterioration, and the stability of these objects salts they contain to variations in climate conditions is an important issue. Responses potassium alum (KAl(SO4)2·12H2O), ammonium (NH4Al(SO4)2·12H2O), bisulfate (KHSO4) alum-treated wood changing temperature relative humidity (RH) were therefore investigated at crystalline level using powder X-ray diffraction (XRD). The XRD analysis showed changes crystal structures that suggest some degree dehydration starting 40 °C 15% RH. Rehydration such dehydrated Oseberg samples was still ongoing after 2 years. However, on their own generally appeared be stable most conditions. Conversely, minor component found very sensitive all RH temperature, may even cause under This related efflorescence K9H7(SO4)8·H2O crystals seen fragments long-term exposure high These findings can help refine limits for objects, also demonstrate utility temperature- RH-controlled qualitative monitoring climate-induced salt-impregnated materials.