A multi-analytical exploration of the chemical composition, microstructural properties and corrosion inhibiting treatment for an archaeological brass censer from Umm Zuwaytinah, Amman

Abstract

This study discusses a multi-analytical exploration of the chemical composition, microstructural properties and corrosion inhibiting treatment for a decorated Byzantine brass censer from Umm Zuwaytinah, Amman. X-ray diffraction (XRD) analysis showed cuprite, brochantite, malachite, atacamite, zincite, and zinc chloride hydroxide as the corrosion products for the censer. Scanning electron microscopy/ energy dispersive X-ray spectroscopy (SEM/EDX) analysis showed α-brass as the alloy of the body and a quaternary Cu, Zn, Sn, Pb as the alloy of the chains of the censer. Optical microscopy examination showed partially recrystallized grains with some annealing twins, strain lines and intergranular corrosion in the body and chain alloys. Microhardness testing results for the censer’s body were consistent with a cast α-brass alloy that was not sufficiently annealed in the manufacturing process, and a drawn quaternary Cu, Zn, Sn, Pb alloy for the chains. SEM examination showed that a treatment bya salicylaldoxime-Paraloid B72 containing solutionwas effective in forming a protective corrosion inhibiting film on the censer's surface.