@Article{AlmeidaSFCGFMCH:2020:ElChSu,
author = "Almeida, D. S. S. and Santos, Denimara Dias dos and Ferreira, N.
B. G. and Correia, C. Q. and Gomes, B. C. and Ferreira, E. A. and
Moreira, L. P. and Castro, J. A. de and Huguenin, J. A. O. and da,
Silva. L.",
affiliation = "{Universidade Federal Fluminense (UFF)} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {Universidade Federal Fluminense
(UFF)} and {Universidade Federal Fluminense (UFF)} and
{Universidade Federal Fluminense (UFF)} and {Universidade Federal
Fluminense (UFF)} and {Universidade Federal Fluminense (UFF)} and
{Universidade Federal Fluminense (UFF)} and {Universidade Federal
Fluminense (UFF)} and {Universidade Federal Fluminense (UFF)}",
title = "Ellipsometric characterization of surface films on AZ31 magnesium
alloy exposed to a Na2SO4 solution",
journal = "Journal of Materials Research and Technology",
year = "2020",
volume = "9",
number = "5",
pages = "10175--10785",
keywords = "Ellipsometry, MgO, Mg(OH)2, Al2O3, Film thickness.",
abstract = "Magnesium is an attractive structural material due to its very low
density. Among the magnesium alloys, the AZ series containing
aluminum and zinc as main alloying elements presents good
mechanical properties. However, the great challenge to be overcome
by these materials is the poor corrosion resistance, consequence
of their high surface reactivity with the formation of
oxide/hydroxide films, which generally offer low protection.
Therefore, to study the surface characteristics of these alloys is
very important. In this paper, the surface of AZ31 magnesium alloy
is characterized by ellipsometry after exposure to a 0.1 M Na2SO4
solution for 3 min, 5 min, 15 min, and 30 min. Through
ellipsometric measurements and proper ellipsometric modeling, the
thickness of the surface films grown for all cited immersion times
could be known. The modeling acknowledges the three-layer surface
film is formed for an inner layer composed initially of mixing of
MgO and Al2O3. As the immersion time progresses until 5 min, the
MgO is successively replaced by magnesium hydroxide (Mg(OH)2),
thickening the intermediate layer of the film, which is composed
of dense Mg(OH)2. On the other hand, the outer layer is composed
of porous Mg(OH)2. The total thickness of the film grows in two
stages: in the first 5 min, the film experiments a disruptive
thickening until 339 nm; between 5 and 30 min, the total thickness
evolves from 339 nm to 386 nm. © 2020 The Authors. Published by
Elsevier B.V. This is an open access article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/).",
doi = "10.1016/j.jmrt.2020.07.030",
url = "http://dx.doi.org/10.1016/j.jmrt.2020.07.030",
issn = "2238-7854",
language = "en",
targetfile = "almeida_ellipsometric.pdf",
urlaccessdate = "28 abr. 2024"
}