The metal alloys from the XIX century and weathering action in the Mercado do Ver-o-Peso building, northern Brazil: Identification with the usage of laboratory analysis

• Ver-o-peso is a heritage building from the 19th century with unidentified alloys.
• Alloy and weathering product characterization was done using SEM/EDS and XRD.
• Four metal alloy types were described, indicating different types of foundries.
• Weathering products showed distinct mineral phases and physical characteristics.
• Original paint coats were found among corrosion products.

The fabrication of metallic buildings started in Europe after the Industrial Revolution in the 18th century. Metallic constructions became very popular, and started being imported by several countries, due to the facility of constructing or assembling. Belém, a northern Brazilian city, holds a great number of buildings entirely made of iron, including the Ver-o-Peso, a fish market which structures were imported from England by the end of the 19th century. This building represents a unique type of architecture and it's an important part of the city's heritage. However, research so far did not focus on its construction materials. Ver-o-Peso building's metal alloys haven't been thoroughly studied concerning physical, chemical and mineralogical characterizations. This paper aims to identify the types of metal alloys used in the building, and also corrosion products' result from weathering actions. The methods used to characterize the materials were scanning electron microscopy and X-ray diffraction. Through this research it was possible to identify four types of iron alloys used in the different parts of the building, characterize the paint coats, and determine types of corrosion. The characterization of the materials in the building allows enrolling basis for restoration processes, documenting the types of metal alloy used in architectural heritage from the 19th century, as well as understanding the advances of corrosion.