Oxidation mechanism of Ni-20Cr foils and its relation to the oxide-scale microstructure

Journal Article · Tue Feb 01 04:00:00 EST 2000 · Oxidation of Metals

DOI:https://doi.org/10.1023/A:1004578513020· OSTI ID:20015574

Calvarin, G; Molins, R; Huntz, A M

The oxidation behavior of Ni-20Cr foils of 100- and 200-{micro}m thickness was studied in air between 500 and 900 C. Simultaneously, the morphology, microstructure, and composition of the oxide layers were determined by scanning and transmission electron microscopies. Depending on the temperature, the oxide layer differed significantly. The scale formed at all temperatures was complex, with an outer NiO layer having columnar grains, and an inner layer of equiaxed NiCr{sub 2}O{sub 4} + NiO + Cr{sub 2}O{sub 3} grains. At low temperatures (500 and 600 C), the chromium content was insufficient to form a continuous Cr{sub 2}O{sub 3} layer, while such a continuous layer formed at the inner interface at oxidation temperatures of 700 to 900 C. At 600 C, internal oxidation of chromium occurred in the substrate. The oxidation mechanism is described taking into account these morphologies and the oxidation kinetics. The observation of no significant differences between the oxidation behavior of thin strips and thick materials is related to the limited exposure times of the study.

• Research Organization: Univ. Paris XI, Orsay (FR)
• OSTI ID: 20015574
• Journal Information: Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 1-2 Vol. 53; ISSN OXMEAF; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM ALLOYS
ELECTRON MICROSCOPY
FOILS
KINETICS
MICROSTRUCTURE
NICKEL ALLOYS
OXIDATION
SCALING
TEMPERATURE DEPENDENCE