Study of lead roofing browning by the GEAIME team
Over the past twenty years or so, a brown patina has been developing on lead roofing installed to protect monuments in the urban landscape, giving these old roofs an unsightly cameo appearance to the point of becoming a cause for concern for those concerned with built heritage. Scientists have taken up this issue, which seems to be linked to plattnerite (PbO2), the formation mechanisms of which are still poorly understood. It is vital to understand how environmental changes can trigger this browning, which is detrimental to the use of lead roofing. The expertise of the Heritage Materials team and its experimental mastery of LISA's CIME - CIME 2 Chambers for Simulation and Material-Environment Interaction, as well as its micro-nano-scale corrosion analysis capabilities, were required to help remove some of the obstacles in this study. Atmospheric weathering of new lead is also necessary to identify the nature of the corrosion product phases that are gradually forming in today's increasingly aggressive environment. The installation of the new lead roof at N-D de Paris confirms the urgent need for this approach.
This collaborative work is based on several projects led by Aurélia AZEMA, head of LRMH's "metal pole" (UPE, ANR-JCJC Embruni projects) and a framework agreement project linked to the N-D de Paris roof elements analysis and inspection contract, led by the A-Corros company (Marine BAYLE and Jean-Bernard MEMET).
More informations :
Chambre de simulation CIME : http://www.lisa.u-pec.fr/fr/instruments/35-instruments/instruments-de-simulation/143-la-chambre-de-simulation-cime
Master MAPE : http://www.master-sge.com/fr/presentation/m2-mape-materiaux-du-patrimoine-dans-l-environnement
Pôle métal LRMH : https://www.lrmh.fr/default/pole-metal.aspx?_lg=fr-FR