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@Article{Ardila-RodríguezMenPerOliTra:2019:TiDiPr,
               author = "Ardila-Rodr{\'{\i}}guez, Laura A. and Menezes, B. R. C. and 
                         Pereira Constancio, Lania Auxiliadora and Oliveira, A. C. and 
                         Travessa, D. N.",
          affiliation = "{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and {Instituto 
                         Tecnologico de Aeron{\'a}utica (ITA)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidade Federal de S{\~a}o 
                         Paulo (UNIFESP)} and {Universidade Federal de S{\~a}o Paulo 
                         (UNIFESP)}",
                title = "Titanium dioxide protection against Al4C3formation 
                         duringfabrication of aluminum-TiO2coated MWCNT composite",
              journal = "Journal of Alloys and Compounds",
                 year = "2019",
               volume = "780",
                pages = "772--782",
                month = "Apr.",
             keywords = "Carbon nanotubes, TiO2 coating, Al4C3, Metal matrix composites.",
             abstract = "Aluminum and aluminum alloys have been very useful in the 
                         industry, mainly in the transport sector. So, is important to 
                         improve their mechanical properties to increase their 
                         applications. Carbon nanotubes (CNTs) could be an excellent 
                         reinforcing phase for metal matrix composites, specifically for 
                         composites with aluminum or aluminum alloy matrix. However, CNTs 
                         dispersion, wettability, and interaction with the matrix must be 
                         improved, without damaging their structure. In this work, 
                         multi-walled CNTs (MWCNTs) were coated by the sol-gel process with 
                         a titanium oxide (TiO2) layer with three different thickness and 
                         calcined at two different temperatures: 500 °C and 750 °C. The 
                         resultant powder was mixed by electrostatic adsorption method with 
                         aluminum powder and cold compacted. To simulate high temperature 
                         processing, the compacted disks were pressureless heated at 850 
                         °C, aiming to check the effect of TiO2 in protecting the MWCNT 
                         when in contact with melted Al. The TiO2 coated MWCNT samples were 
                         characterized by a range of analytical techniques including 
                         Field-Emission Gun Scanning Electron Microscopy (FEG-SEM), X-ray 
                         diffraction (XRD), Z-Potential, BrunauerEmmettTeller (BET), Energy 
                         Dispersive X-Ray Spectroscopy (EDS) and Raman Spectroscopy (RS). 
                         The effect of the TiO2 layer as a protective barrier on the MWCNT 
                         against the Al4C3 formation during the heating process and the 
                         hardness of the Al/MWCNT (coated and uncoated) composite were 
                         studied. The results show that the MWCNT were successful coverage 
                         by a uniform amorphous TiO2 layer. After calcination at 500 °C and 
                         750 °C, the layer was completely crystallized into a TiO2 film, 
                         with reduced surface area and pore volume. Electrostatic 
                         adsorption between TiO2 covered MWCNT and Al powders in aqueous 
                         suspension was found to disperse the reinforcing phase prior to 
                         consolidation. On the heat-treated discs, the formation of Al4C3 
                         phase was observed to occur only for uncoated MWCNT samples, 
                         showing that the TiO2 layer effectively protected the nanotubes in 
                         presence of melted Al. The microhardness of the heated samples was 
                         increased up to 26% when reinforced with MWCNT and up to 46% when 
                         reinforced with TiO2 coated MWCNT, compared with pure aluminum.",
                  doi = "10.1016/j.jallcom.2018.12.020",
                  url = "http://dx.doi.org/10.1016/j.jallcom.2018.12.020",
                 issn = "0925-8388",
             language = "en",
           targetfile = "rodriguez_titanium.pdf",
        urlaccessdate = "03 dez. 2020"
}


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