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Title: The effect of strain induced by Ag underlayer on saturation magnetization of partially ordered Fe16N2 thin films

Small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM) were used to study film formation by magnesium alloys AZ31B (Mg-3Al-1Zn base) and ZE10A (Elektron®717, E717: Mg-1Zn + Nd, Zr) in H2O and D2O with and without 1 or 5 wt.% NaCl. No SANS scattering changes were observed after 24 h D2O or H2O exposures compared with as received (unreacted) alloy, consistent with relatively dense MgO-base film formation. However, exposure to 5 wt.% NaCl resulted in accelerated corrosion, with resultant SANS scattering changes detected. The SANS data indicated both particle and rough surface (internal and external) scattering, but with no preferential size features. The films formed in 5 wt.% NaCl consisted of a thin, inner MgO-base layer, and a nano-porous and filamentous Mg(OH)2 outer region tens of microns thick. Chlorine was detected extending to the inner MgO-base film region, with segregation of select alloying elements also observed in the inner MgO, but not the outer Mg(OH)2. Modeling of the SANS data suggested that the outer Mg(OH)2 films had very high surface areas, consistent with loss of film protectiveness. Here, implications for the NaCl corrosion mechanism, and the potential utility of SANS for Mg corrosion, are discussed.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [3]
  1. Univ. of Science and Technology Beijing, Beijing (China); Univ. of Minnesota, Minneapolis, MN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. of Minnesota, Minneapolis, MN (United States)
  4. Univ. of Science and Technology Beijing, Beijing (China)
Publication Date:
OSTI Identifier:
1157178
Grant/Contract Number:
AC05-00OR22725; AR0000199; 51331002; 51371027
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 103; Journal Issue: 24; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; THIN FILMS; STRAINS; IRON NITRIDES thin films; Ag; Magnetic; strain; Fe₁₆N₂; iron nitride