TiO2 and SiO2 nanoparticles film for cultural heritage: Conservation and consolidation of ceramic artifacts

• Consolidation of ceramic artifacts using SiO2 and TiO2 nanoparticles (NPs)
• NP restoration process strongly influences the natural luminescence emission.
• Colloidal solutions were spray-dried on pottery surfaces, obtaining transparent film of about 1 micron.
• NPs consolidate the artifact penetrating in the deeper surface.

In this work, we introduce a new method for the consolidation of ceramic artifacts using SiO2 and TiO2 nanoparticles (NPs). We study the influence of NPs in the restoration process based on luminescence diagnostics and dating techniques. The nanoparticles were grown by laser ablation in solution and their shape and dimensions were monitored by optical absorption and AFM morphology studies. The colloidal solutions are mainly made of spherical nanoparticles with dimensions of about 10 and 15 nm following a LogNorm distribution with a standard deviation less than 1 nm. The colloidal solution was then deposed on pottery surfaces to obtain a transparent film with thickness of about 1 μm. All chemical and morphological analysis indicate that the NPs consolidate the artifact penetrating in the deeper surface layer and forming a transparent and hydrophobic film on the surface. The adsorption process is a typical physisorption mechanism without formation of chemical bonds between the NPs and the constitutive elements of ceramic and without introduction of external impurities, which can damage the materials. Finally, our results indicate a strong influence of NPs on the luminescence emission by the artifacts and then in the thermoluminescence dating process for restored ceramics.