The Rosenburg method was used to determine the physicochemical properties of the oxide at 900 to 1000C, under O pressures ranging from 0.005 to 0.1atm. The defect concentration was proportional to the fourth root of the O partial pressure, while the defect diffusion coefficient was essentially independent of the ambient O pressure. This was explained by assuming that it reflected a predominance of neutral Cu vacancies. The formation enthalpy of neutral Cu vacancies was observed to be about 60kJ/mol, while the formation entropy was about -11J/molK. The migration enthalpies and entropies, as
calculated from the temperature dependence of defect diffusion, were about 54kJ/mol and 5.8J/molK, respectively. Combining the enthalpies of formation and migration of vacancies yielded an enthalpy for Cu self-diffusion of about 115kJ/mol.
Determination of Thermodynamics and Kinetics of Point Defects in Cu2O using the Rosenburg Method. R.Haugsrud, T.Norby: Journal of the Electrochemical Society, 1999, 146[3], 999-1004
Table 88
Diffusivity of 64Cu in Cu2O
Temperature (C) | PO2 (atm) | D (cm2/s) |
999.3 | 7.94 x 10-2 | 3.82 x 10-8 |
996.5 | 7.57 x 10-3 | 2.35 x 10-8 |
1001.7 | 8.29 x 10-4 | 1.64 x 10-8 |
997.7 | 7.91 x 10-5 | 1.07 x 10-8 |
997.6 | 5.99 x 10-6 | 7.23 x 10-9 |
1000.6 | 5.99 x 10-6 | 7.13 x 10-9 |
900.0 | 8.30 x 10-3 | 9.40 x 10-9 |
899.7 | 8.29 x 10-4 | 6.53 x 10-9 |
900.3 | 7.55 x 10-5 | 4.18 x 10-9 |
900.1 | 6.88 x 10-6 | 3.02 x 10-9 |
802.6 | 9.09 x 10-4 | 1.94 x 10-9 |
799.0 | 9.09 x 10-4 | 1.86 x 10-9 |
801.7 | 7.21 x 10-5 | 1.51 x 10-9 |
802.6 | 6.88 x 10-6 | 1.01x 10-9 |
802.3 | 1.14 x 10-6 | 7.29 x 10-10 |
1153.4 | 5.22 x 10-5 | 4.12 x 10-8 |
1135.8 | 7.55 x 10-5 | 3.79 x 10-8 |
1100.8 | 7.55 x 10-5 | 2.73 x 10-8 |
997.7 | 7.91 x 10-5 | 1.07 x 10-8 |
936.6 | 7.55 x 10-5 | 5.81 x 10-9 |
900.3 | 7.55 x 10-5 | 4.18 x 10-9 |
801.7 | 7.21 x 10-5 | 1.51 x 10-9 |
701.9 | 7.55 x 10-5 | 3.97 x 10-10 |
700.3 | 7.55 x 10-5 | 3.89 x 10-10 |