Síntese pelo método pechini e caracterização da zircônia dopada com cério e neodímio
In this study five compositions were synthesized zirconia doped with cerium and neodymium ions in the system Ce10-xNdx Zr90O2 with 0,5 ≤ x ≤ 4,0 using the Pechini method. The powders were characterized by thermogravimetric analysis, differential thermal analysis, infrared spectro...
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| Formato: | doctoralThesis |
| Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/17754 |
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| Resumo: | In this study five compositions were synthesized zirconia doped with cerium and
neodymium ions in the system Ce10-xNdx Zr90O2 with 0,5 ≤ x ≤ 4,0 using the Pechini
method. The powders were characterized by thermogravimetric analysis, differential thermal
analysis, infrared spectroscopy and X-ray diffraction, with application of Rietveld
refinement of the calcination temperatures of 350ºC/3h and 30 minutes at 900ºC/3h. All
compositions stabilized with a mixture of cubic and tetragonal phase zirconia. The samples
were pressed into bars and sintered at 1500°C/3h and 1500°C/6h, being characterized by Xray
diffraction, with application of the Rietveld refinement, density and porosity using
Archimedes method, scanning electron microscopy and resistance the three point bending. It
has been observed the increase in strength with increasing sintering temperature for the
compositions x = 2,0 and x = 4,0. For x = 2,0 the main phase was the cubic with 92,56%
with crystallite size of 0,56 μm, density and porosity of 96,82% from 1,36%. For x = 4,0
was a mixture of cubic and tetragonal phase with 21% and 37,98%, respectively. The
crystallite size was 54,21 nm and 49,64 nm with a density porosity of 97,45% and 1,32%
respectively. In the analysis of the fracture surface was observed a greater amount of grain
fracture intragranular type, which contribute to increase the mechanical strength of the
ceramic. Increased addition of the neodymium ion in the crystal lattice of the zirconium
showed a nearly linear behavior with increasing mechanical strength of the zirconia ceramic.
Was obtained a bending resistance of 537 ± 38 MPa for the composition x = 2,0
predominantly attributed to cubic phase with 92,56% |
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