@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 = "28 abr. 2024"
}