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 = "21 abr. 2021"