Scientific investigation of the 20th century bronze bell in Asyut, Egypt: insight into materials, chemical composition and preservation status

Abstract This research presents an historical background and an analytical and study of a bell dating back to the 20th century, currently located at Al Salam Modern School, an ancient school, formerly known as the American College in Asyut, Egypt, which was established during the period between 1901 and 1909. The bell consists of metal parts (Bowl, Yoke, Standards, Clapper, Clevis Bolt, Toller, and Bearing) and wooden parts (Base or Frame and Wheel). These components were studied and analyzed using microscopic examination, Portable X-ray fluorescence (p-XRF) Scanning electron microscopy (SEM), coupled with an energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Visual and microscopic examination revealed the presence of corrosion products on the surface of the bell and its metal parts, bird droppings, embrittlement of the wood structure, fiber breakage, and accumulation of dust. The bell’s wooden parts were identified as oak using a light microscope. The body of the bell itself was analyzed using p-XRF and EDX, which revealed that the alloy used for its making is mainly composed of copper and tin, known as tin-bronze alloy. XRD analysis was used to identify the corrosion products on the surface of the bronze bell as well as the corrosion products of the parts made of iron. The results revealed that the corrosion products formed on the bell surface are Nantokite, Paratacamite, Atacamite, Brochantite, Antlerite, Cassiterite and Gypsum, while the rust products on the iron parts are Magnetite, Hematite, Goethite, Akaganeite, Lepidocrocite and Gypsum. FTIR analysis of the wooden parts of the bell showed the embrittlement and the decomposition of hemicellulose and lignin. This analysis also showed that the paints used in painting the wooden parts is a local paint known as ARTEX (Pachin).