Kinetic equation based on non-steady-state diffusion of oxygen in solid copper
(1. State Key Laboratory for Mechanical Behavior of Materials,
Xi′an Jiaotong University, Xi′an 710049, China;
2. School of Materials Science and Engineering,
Henan University of Science and Technology, Luoyang 471003, China;
3. Dongfeng Motor Co Ltd, Shiyan 442042, China)
Xi′an Jiaotong University, Xi′an 710049, China;
2. School of Materials Science and Engineering,
Henan University of Science and Technology, Luoyang 471003, China;
3. Dongfeng Motor Co Ltd, Shiyan 442042, China)
Abstract: The kinetics of internal oxidation of dilute Cu-Al alloys, containing 0.4475%-2.214%Al(mole fraction) was investigated over the temperature range of 1023-1273K and the depth of internal oxidation was measured by microscopy. Based on non-steady-state diffusion, a rate equation is derived to describe the kinetics of internal oxidation of plate: X=k(t)1/2, where X is the oxidation depth, t is the oxidation time. For the internal oxidation of Cu-Al alloys employed in the synthesis of alumina dispersion strengthened copper, the permeability of oxygen in solid copper is obtained from the internal oxidation measurements. Investigation shows that the depth of the internal oxidation is a parabolic function of time, the typical shape of the front of internal oxidation is of planar morphology, and there is no evidence for preferential diffusion along grain boundaries.
Key words: Cu-Al alloys; non-steady-state diffusion; internal oxidation; rate equation