Y-TZP reinforced with reduced graphene oxide
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Dental Materials
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Purpose/aim: To develop a processing method for yttrium
stabilized zirconia pollycrystal (YTZP) reinforced with reduced
graphene oxide (rGO) and to verify the effect of rGO concentration
on hardness and fracture toughness of the material.
Materials and methods: The composite production
included several steps: (a) synthesis of Y-TZP powder by
coprecipitation route, (b) synthesis of graphene oxide from
chemical exfoliation of graphite (modified Hummer’s method)
followed by reduction with ascorbic acid, (c) sonication of
reduced graphene oxide in Y-TZP suspension followed by
drying (d) uniaxial pressing in metal device with diameter
of 5mm and (e) sintering in a conventional tubular furnace
(Argon/4%hydrogen atmosphere) or spark plasma sintering
(SPS). The concentration of rGO in Y-TZP was fixed between
0.01 and 2.0 wt%. Sintered samples were characterized by
X-ray diffraction, scanning electron microscopy, density measurements,
and Vickers method for hardness and fracture
toughness determination (indentation fracture). Data were
analyzed by ANOVA and Tukey’s test with global significance
level of 5%.
Results: Results (Table 1) showed that the procedure stablished
for dispersion of rGO in the Y-TZP resulted in good
physical homogeneity of rGO and Y-TZP. Regarding the sintering
procedure, it was observed that conventional sintering in
a controlled atmosphere was not effective for ceramic densification
due to microcrack formation at the ceramic surface. For
conventional sintering, the hardness obtained for the rGO concentration
of 2% was significantly lower than those obtained
for all other concentrations, however, for this processing
method, fracture toughness was not affected by rGO concentration.
For SPS, both fracture toughness and hardness were affected by rGO concentration, with the lowest hardness mean
value measured for the concentration of 0.05% and the lowest
fracture toughness value measured for specimens with
addition of 0.01% of rGO.
Conclusions: The production of the composite Y-TZP/rGO
was proved possible, and sintering via spark plasma resulted
in higher mechanical properties of the composite material
compared to conventional sintering. rGO concentration
affected the hardness of the composite for both processing
methods (conventional and SPS), however fracture toughness
was only affected by rGO concentration for specimens
processed via SPS.
Como referenciar
MANARAO, D.S.; CORDEIRO, G.L.; TERTULIANO, A.J.O.; MACHADO, I.F.; LAZAR, D.R.R.; USSUI, V.; CESAR, P.F. Y-TZP reinforced with reduced graphene oxide: evaluation of processing conditions. Dental Materials, v. 34, p. e72-e73, 2018. Suppl. 1. DOI: 10.1016/j.dental.2018.08.149. Disponível em: http://repositorio.ipen.br/handle/123456789/29781. Acesso em: 30 Dec 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.