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Nanocrystallization process of the Fe 69.5 Cu 1 Nb 3 B 9 Si 13.5 Cr 4 FINEMET‐type alloy: an AFM study
Author(s) -
Salinas D. R.,
García S. G.,
Bessone J. B.,
Pierna A. R.
Publication year - 2000
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/1096-9918(200008)30:1<305::aid-sia792>3.0.co;2-f
Subject(s) - devitrification , nanocrystalline material , materials science , crystallization , amorphous solid , annealing (glass) , atomic force microscopy , alloy , nanocrystal , metallurgy , corrosion , surface roughness , amorphous metal , chemical engineering , analytical chemistry (journal) , composite material , crystallography , nanotechnology , chemistry , engineering , chromatography
The different devitrification stages of Fe 69.5 Cu 1 Nb 3 B 9 Si 13.5 Cr 4 (F‐Cr4) amorphous alloy were studied by atomic force microscopy (AFM) on samples annealed at 400, 600 and 670 °C for different treatment times. The AFM images showed no topographic changes in the alloys treated at 400 °C, indicating that only structural relaxations took place at this annealing temperature. Samples thermally treated at 600 °C showed hemispherical features uniformly distributed on the surface, suggesting initiation of the nanocrystallization process. The nanocrystals formed had a size distribution of 15–40 nm, which is slightly affected by the annealing time. At 670 °C the crystallization phenomena occurred with the formation of large crystals and an increase in roughness. The corrosion behaviour of the nanocrystalline alloys in 2 M HCl solution was correlated with the AFM studies. The potentiodynamic experiments for these alloys showed a significant decrease of the current density peak at the active–passive transition in relation to the F‐Cr4 amorphous alloy. The results indicated that the corrosion resistance and passivating ability of the alloys are improved by the thermal treatment. Copyright © 2000 John Wiley & Sons, Ltd.