Abstract
The parabolic oxidation of nickel has been studied between 900° and 1400°C at pressures from the dissociation pressure of nickel oxide to 1 atm of oxygen. The activation energies in various atmospheres were found to range from 36.3 to 43.6 kcal/mole. The usual equation for parabolic oxidation, 
did not hold over the entire pressure range because the value of 
varied with temperature. A marker study showed that the markers were located close to the metal‐oxide interface. A method for obtaining the self‐diffusion coefficient of the more mobile ionic species in the oxide is proposed.