Chemical diffusion measurements in single crystalline cuprous oxide

Abstract

Using electrical conductivity measurements in the temperature range 650–1100°C and for oxygen pressure greater than 10 −6atm., the variation of the chemical diffusion coefficient in cuprous oxide with temperature has been determined as: D ̃ = 1.2 10 −3 exp ( − 7800 RT ) cm 2 sec −1 . Taking into account the nature of the prevailing defects in cuprous oxide one can show that D ̃ ≅D Cu [V x Cu ] . This relation permits the results to be compared with those determined by tracer diffusivities. Using a value for the enthalpy of formation of non ionized copper vacancies in the range 12–16 kcal mol −1, the results are shown to be in agreement with the value of the activation enthalpy for self-diffusion of copper of 24 kcal mol −.