Page 315 - 00. Complete Version - Progress Report IPEN 2014-2016

Materials and Nanotechnology | Progress Report 315

have been deposited using a Successive Ionic forms a composite.
Layer Adsorption and Reaction (SILAR) tech-
nique. Zinc oxide nanorods prepared in this In this project copper alloys were developed
SILAR facility are also being employed to pro- by powder metallurgy for use in electrical ap-
duce supercapacitors for energy storage and plication, including fuel cell. The studied com-
several undergraduate students are engaged posite has a ternary metal alloy (copper, chro-
in these investigations. mium and silver) as a matrix and a ceramic
oxide (alumina or ceria) as the reinforcing
Copper based composites for phase. The addition of chromium, silver and
electrical application tin amounts of finely dispersed metal oxides

in copper improves their mechanical proper-
ties and increases the operating temperature,
causing little loss of conductivity. A possible
application of these composites is as anodes
in Solid Oxide Fuel Cells (SOFC) (Figure 38).

Cermets based on rare earth oxides and met-
als such as copper, silver and chromium) have
been studied (80% Cu – 20% CeO2; 80% Cu – 8%
Cr – 4% Ag – 8% CeO2; 80% Cu – 20% Al2O3;
80% Cu – 8% Cr – 4% Ag – 8% Al2O3). The aim of
this study involves microstructural character-
Figure 38: Chemical-electric energy conversion device. ization (optical microscopy, scanning electron
microscopy, and X ray diffraction of compos-
Copper and its alloys have been used in func- ite processed by powder metallurgy. The sam-
tion of the high thermal and electrical con- ples used were fabricated in laboratory scale
ductivity, good mechanical properties, resis- of 25 mm diameter, 3.5 mm ≥ h ≥ 4.0 mm of
tance to corrosion, ease of fabrication and by height and 6,5 g of mass.
the high value of scrap. Metal alloys can also
be combined with other classes of materials To obtain the samples, the powders were
to obtain new properties, superior to the orig- weighed on a precision balance (according
inal alloy, this union of two or more materials to each composition), mixed manually and

Figure 39: Optical micrographs of the composites Cu-Cr-Ag-(CeO2, Al2O3) in normal and transversal directions, as polished (100 µm scale).