Protection of lead by preservation acrylic coatings in acetic vapors environment

A lead was used in the past in a variety of applications for example for roofs of churches, garden ornaments, lead seals, and organ pipes. Lead alloys are susceptible to a corrosion attack in an environment containing volatile organic compounds especially acetic acid vapors. The source of acetic acid vapors is mainly wood, glued joints, some varnishes, plastics, and paints. In the acetic acid vapors environment, the corrosion rate of Pb alloys rapidly increases. The study of protective properties of acrylic coatings of lead (Paraloid 72, B48N a B44) in an environment containing acetic acid vapors was the aim of this work. The acrylic coatings were prepared with or without 1,2,3, - Benzotriazole (BTA). Painted lead samples were exposed in an environment containing acetic acid vapors for 8 weeks. The color change of lead surfaces was observed by a spectrophotometer during the exposition. The preservation effect of acrylic coatings were evaluated by the mass gain of lead samples during the exposition. The surface of the lead samples after exposition was observed by optical microscopy, and X-ray diffraction analysis. The research proved that the Paraloid B44 with BTA has the best protective properties of lead in an environment containing acetic acid vapors from all tested coatings.