Segregation of cerium in chromia scales
1990; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-08-040423-3.50013-6
AutoresDavid A. Downham, R. J. Hussey, D. F. Mitchell, M. J. Graham,
Tópico(s)Fusion materials and technologies
ResumoThe oxidation rate of Fe-Cr alloys at 900-1100°C is significantly decreased by the presence of a thin (~40Å) sputter coating of Ce02. 18O/SIMS experiments show that Ce found within the scale changes the mechanism of Cr2O3 growth from predominantly cation to predominantly anion diffusion, both of which are considered to occur along oxide grain boundaries. For oxides > 1000 Å thick, EDX, EELS, TEM and electron diffraction data indicate that Ce segregates to form particles of CeCr03 which likely retard grain boundary diffusion of Cr cations. Analogous results are observed for Y203-coated and Y-implanted alloys.
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