Evaluation of reduced graphene oxide -reinforced zirconia ceramics processing conditions
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2018
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INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62.
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Yttria tetragonal zirconia polycrystal (Y-TZP) has been widely used as dental and
orthopaedic implants. However, the lack of stability of the tetragonal phase in water
environment can induce damages on the ceramic surface due to the transformation
into the monoclinic phase. The reduction of ceramic grain size can avoid this phase
transformation, despite the loss of transformation toughening benefits. In order to
minimize this drawback, the incorporation of a second phase into the zirconia matrix
has been recently considered. The aims of the present contribution were to establish
the procedure of ceramic processing of reduced graphene oxide -reinforced zirconia
ceramics and to verify its influence on hardness and fracture toughness. 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 and (e) sintering in a conventional tubular furnace (Argon/
4%hydrogen atmosphere) and spark plasma sintering (SPS). The concentration of
rGO in Y-TZP was fixed between 0.01 to 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. Results showed that the procedure stablished for dispersion of rGO in
Y-TZP allowed a 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. Employing 0.05 rGO wt% in Y-TZP ceramic associated to spark
plasma sintering at 1350oC allowed density higher than 98%DT and hardness and
fracture toughness up to 14.4 GPa and 7.8 MPam1/2.
Como referenciar
USSUI, V.; MANARAO, D.S.; CORDEIRO, G.L.; TERTULIANO, A.J.O.; MACHADO, I.F.; LAZAR, D.R.R.; CESAR, P.F. Evaluation of reduced graphene oxide -reinforced zirconia ceramics processing conditions. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... p. 120-120. Disponível em: http://repositorio.ipen.br/handle/123456789/29682. Acesso em: 19 Apr 2024.
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.