Mohammed Samir Elmetwaly

Citation:

Mohamed, W. A., Rifai, M. M., Ghany, N. A. A., and M. S. Elmetwaly, "Testing Coating Systems for Bare and Patinated Outdoor Bronze Sculptures", Proceedings of the interim meeting of the ICOM-CC metals working group, Metal 2016, Edited by Menon, R., Chemello, C. and Pandya, A. , New Delhi, India, pp. 161-169, 2016.

Abstract:

This research aims to evaluate the performance of selected coating systems for the protection of outdoor bronze sculpture. The coating systems were applied onto bare (unpatinated) and patinated bronze coupons, to investigate whether the patination of outdoor bronze sculpture prior to coating with different systems can enhance their protection. Quaternary bronze alloy coupons (Cu-Sn-Zn-Pb) were prepared to simulate the composition of alloys typically used for casting outdoor bronze statuary in the 19th century. The coating materials tested include; ORMOCER, Incralac, Microcrystalline wax (Cosmoloid H80), Benzotriazole BTA (Pretreatment) + Incralac, Incralac + Microcrystalline wax (Cosmoloid H80) top coat, Benzotriazole BTA (Pretreatment) + Incralac + Microcrystalline wax (Cosmoloid H80) and Acryloid B-44.

Weight gain, color change and electrochemical impedance spectroscopy (EIS) were used to compare the performance of the proposed coating systems and assess their efficiency in actual outdoor conditions and in the laboratory. The results indicated that the best coating systems that met both aesthetic and protection requirements were afforded by BTA (Pretreatment) + Incralac for bare bronze and Benzotriazole BTA (Pretreatment) + Incralac + Microcrystalline wax for patinated bronze.