Abstract
Absorption rate of hydrogen by copper specimens containing 0.25% and 1.0% oxygen, respectively, at various temperatures (350∼700°C) were measured. In 0.25% oxygen copper specimens, the amount of absorbed hydrogen increased with time rather linearly than quadratically, especially at higher temperatures. The relation between the logarithm of the initial rate and the reciprocal of absolute temperature was almost linear and the activation energy was deemed to be 18 kcal/mol, which was near the activation energy of diffusion of hydrogen in thin copper plate. The rate-determining step of absorption is looked upon as the diffusion of hydrogen, and it is supposed that grains of cuprous oxide are only reduced by interaction with hydrogen which have reached there. The topochemical aspect of the reduction was normal, namely, the boundary between the reduced part and the unreduced part was parallel to the surface. In 1.0% oxygen copper specimens, irregularlly reduced parts were observed in much deeper places besides the normally topochemically reduced parts. At those abnormally reduced parts the absorption of hydrogen was supposed to have been done very quickly.
