During the demolition of an old barn in Florida, New York, several nineteenth century brass sleigh bells were uncovered (Figure 1). The accumulated corrosion product was removed in a nitric acid solution, and as a result of cursory examination, several cracks were observed. These cracks probably developed long before the cleaning operation since nitric acid is known to favor general corrosion1 and thus not cause intergranular attack of copper base alloys. A light optical micrograph of such a crack is shown in Figure 2. The approximate composition of the bells, as determined by X-ray fluorescence, is 73 Wt% Cu plus 27 Wt% Zn.
In attempting to establish the origin of the failure, it was noted that the cracks were associated with the most highly deformed regions of the bell. This led to the opinion that, as a result of the fabrication operation, the bells are in...
