Metal corrosion in polychrome baroque lead sculptures: a case study

Autor(es)

de Faria, Dalva L. A. ^[1] ; Puglieri, Thiago S. ^[1] ; Souza, Luiz Antonio C. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, BR-05508000 Sao Paulo - Brazil

^[2] Univ Fed Minas Gerais, Lab Ciencia Conservacao Lacicor, Escola Belas Artes, BR-31270901 Belo Horizonte, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Chemical Society; v. 24, n. 8, p. 1345+, AUG 2013.
• Citações Web of Science: 2

Resumo

Polychrome lead sculptures from Oratory Museum in Ouro Preto (Minas Gerais, Brazil) kept inside a glass showcase were severely degraded. The formed corrosion products were analyzed by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDX) and Raman microscopy and proved to be mostly Pb carbonates and formates. Although carbonate is a very common finding in Pb atmospheric corrosion, Pb formates can be formed by the action of formic acid or formaldehyde, being their origin a key point to be investigated. Environmental simulations with Pb coupons exposed to possible sources of these volatile organic compounds led to the conclusion that the degradation process was caused mainly by the curing process of the painted showcase baseplate. However, cleaning products, which can also contain formaldehyde as preservative, proved to be potentially harmful to Pb, accelerating its corrosion. (AU)

• Processo FAPESP: 08/56127-0 - Efeitos sinérgicos na degradação de materiais pictóricos: papel de íons metálicos na degradação de gorduras e na geração de ácido fórmico
• Beneficiário: Thiago Sevilhano Puglieri
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 11/13760-8 - Impacto da composição química de microambientes em bens culturais: mecanismos e monitoramento
• Beneficiário: Thiago Sevilhano Puglieri
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 06/58748-7 - Reatividade, dinâmica e espectroscopia de sistemas complexos
• Beneficiário: Marcia Laudelina Arruda Temperini
• Modalidade de apoio: Auxílio à Pesquisa - Temático