ISSN:
1573-4889
Keywords:
nickel
;
sulfidation
;
multilayer scale
;
diffusion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The reaction between pure nickel and sulfur vapor has been studied over the temperature range 380–475° C. A scale consisting of four separate layers is formed and the growth of the three outer layers obeys parabolic kinetics. The innermost layer grows only in the very early stages, after which the thickness remains approximately constant. The layers have been identified as three different sulfides-Ni3S2, which forms the two inner layers, Ni7S6, and NiS. The three outer layers grow with preferred orientations; growth of the Ni3S2 and NiS layers is with the basal planes of their hexagonal structures parallel to the nickel substrate. The formation of the scale can be described in terms of a diffusion-controlled process and the same basic process continues after scale-metal separation occurs. The description of scale growth is combined with experimental data to calculate the diffusion coefficient of nickel ions in each phase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00603855
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