Applicability and efficacy of an enhanced nanolime consolidation technique for British Museum limestone objects

Stone consolidation is one of the most important and complex treatment actions performed in museums. However, products routinely applied on limestone objects are often chemically incompatible with the treated substrate. Despites the established efficiency of nanolime for outdoor conservation and its chemical compatibility with the carbonate mineral matrix, its performance in a museum context needs to be verified. As a result, this work addresses a shortcoming in the field of Stone Conservation as nanolime has never been officially introduced in museums before. Three British Museum limestone objects affected by superficial damages were treated using an Enhanced Nanolime Consolidation Technique (En−NCT) which was developed in the Materials Engineering Research Institute (Sheffield Hallam University) and tested for the first time in a museum context. The results show that the use of alcoholic nanolime by means of a tailored consolidation technique is a realistic and promising museum conservation approach. The En−NCT does not impair the aesthetical appearance of the objects and restores the mineral cohesion of the treated surface by increasing the hardness of the near-to-surface layers.