Understanding soil factors in corrosion and conservation of buried bronze statuettes: insights for preservation strategies

Abstract

The findings reveal that soil constituents significantly affect the corrosion process. Moisture content and pH promote the formation of corrosion products, while high chloride concentrations accelerate corrosion. Conversely, high organic matter content inhibits corrosion by limiting oxygen diffusion to the metal surface. The effectiveness of conservation treatments, particularly wax or oil-based coatings, varied with soil conditions, showing reduced efficacy in soils with high chloride concentrations. This study underscores the importance of understanding soil constituents for developing effective corrosion and conservation strategies for buried bronze statuettes. The results offer valuable insights for customizing preservation approaches based on soil types. X-ray diffraction (XRD) analysis revealed that mineralogical compositions in soil significantly influence corrosion processes, providing critical insights for effective preservation strategies. pH measurements indicated varying soil acidity and alkalinity levels, crucial in determining corrosion rates and mechanisms, offering essential data for targeted preservation strategies. Additionally, the identification of brochantite and antlerite through Micro-Raman spectroscopy suggests a link to sulfur pollutants from the decomposition of organic matter by sulfate-reducing bacteria, highlighting the potential environmental impact of microbial activity in the soil ecosystem.