Oxidation Behavior of Cu-Pb Bearing Alloys

The oxidation kinetics of Cu-Pb bearing alloys was investigated under a temperature domain between 25 and 700 °C. It has been found that during oxidation process, lead was easy to diffuse in the channel formed inside the alloy and form oxide film on the surface of the alloy. The oxides formed by Pb at different oxidation temperatures show different morphologies, and there was no obvious change at 25 °C. However, the PbO formed by oxidation at 180 and 300 °C was spherical, and the Pb 3 O 4 formed by oxidation at 500 °C was small flake distribution. At 700 °C, granular PbO was covered on the alloy surface. Sn and Cu were oxidized to SnO 2 and CuO. Pb 3 O 4 and PbO as oxidation products of Pb diffused at the alloy surface as the oxidation period increased. The oxidation weight gain curve of Cu-Pb alloy followed a parabolic law for 300 h at 25 °C. As the time increased, a straight line is noticed very close to zero. For a temperature range between 180 and 700 °C, the oxidation weight gain curves followed again a parabolic law.