Also, aluminum oxide is insoluble in water, therefore the aluminum oxide in contact with water doesn't increase the corrosion process. 0.40 Volts which provides the potential for other half-cells in a metal corrosion process. In this experiment we deal with pure copper metal. Copper is thermodynamically unstable so it combines with other elements or compounds to create more stable copper compounds. Table 3 lists many common copper corrosion compounds.
Bronze is an alloy made of copper which also contains tin and lead.
Bronze corrodes faster than pure copper objects. Archaeologists have identified bronze disease which attacks the surface of bronze metal. Although on bronze the normal patina of cuprite and malachite is stable and protective, there is often a layer of cuprous chloride below it on the metal surface. In dry conditions this chemical is stable, but if moisture penetrates through the outer layers the cuprous chloride it becomes unstable, absorbs water, and is converted to basic cupric chloride which can produce powdery light green spots on the surface. This condition is known as bronze disease.