The influence of crystallographic orientation of nickel surface on oxidation inhibition by ceria coatings

Journal Article · Fri Feb 13 04:00:00 EST 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00240-1· OSTI ID:605858

Czerwinski, F; Szpunar, J A ^[1]

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1. McGill Univ., Montreal, Quebec (Canada). Dept. of Metallurgical Engineering

The growth of NiO on (100) and (111) crystal faces of Ni, both pure and coated with nanosized CeO{sub 2} particles, has been studied at temperatures in the range of 873--1,073 K. It is shown that the crystallographic orientation of the substrate exerted an essential influence on the growth rate and microstructure of pure and CeO{sub 2}-modified NiO. The 14 nm thick coatings of CeO{sub 2} deposited on (100)Ni markedly inhibited the oxidation process; however, oxide growth rate on this face was still higher than that measured for uncoated (111)Ni. The same coatings applied to (111)Ni, when incorporated into the oxide without the coarsening of CeO{sub 2} particles, decreased the oxidation rate to values as low as that predicted from the lattice diffusion of Ni n NiO. The differences in the oxidation rate of both Ni crystal faces are interpreted by the changes in oxide microstructure and texture, in terms of the type and density of grain boundaries. It is suggested that, at high temperatures, the NiO grain boundaries act as easy-diffusion paths for Ce{sup 4+} ions and primarily affect the distribution of relative element in oxide. Subsequently, the Ce{sup 4+} segregation affects the relative suppression of Ni{sup 2+} and O{sup 2{minus}} diffusion, and the dominant oxidation mechanism.

• OSTI ID: 605858
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 4 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
CORROSION PROTECTION
CORROSION RESISTANCE
GRAIN ORIENTATION
NICKEL
NICKEL OXIDES
OXIDATION
PROTECTIVE COATINGS