The reactive element effect on the growth rate of nickel oxide scales at high temperature

The restriction of oxide-scale growth by an incorporated reactive element has been investigated for the oxidation at 900°C of CeO₂-coated and Ce-alloyed Ni. Analytical electron microscopy of scales in transverse section revealed that significant inhibition of diffusion along a network of grain-boundary pathways in NiO was associated with segregation of Ce at a high concentration. The development of this form of Ce distribution depended critically on the provision of sufficiently small and closely spaced CeO₂ source particles within the scales.