Hard and tough carbon nanotube-reinforced zirconia-toughened alumina composites prepared by spark plasma sintering

Echeberrı́a, J.; Rodríguez, N.; Zhang, Fei; Vanmeensel, Kim; Reyes‐Rojas, A.; Garcia‐Reyes, A.; Domínguez-Ríos, Carlos; Aguilar-Elguézabal, A.; Bocanegra‐Bernal, M.H.

doi:10.1016/j.carbon.2011.09.031

Cited by 68 publications

(31 citation statements)

References 65 publications

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“…The rough finish observed is due to pull-out of the alumina grains, which takes place during the polishing process of the composites. This is in agreement with the observations of Echeberria et al [25] on rougher finishing in surfaces with small alumina grains and CNTs compared to flat finishing in areas consisting of large-grains without CNTs. These latter zones are inexistent in our composites due to the adequate dispersion of SWNTs achieved.…”

Section: Microstructural Characterizationsupporting

confidence: 93%

“…These optical images of typical indenter marks also show that polished surfaces have a rough finish due to grain pull-out during polishing. Vickers sites also exhibit typical lack of classical radial cracks in the indentation impression [6,25]. The finding of unaffected carbon nanotubes by the indenter tip-CNT direct interaction during the indentation load cycle [22] supports that the contact between the indenter tip and elastic SWNT agglomerates prevents the formation of imprints properly.…”

Section: Evaluation Of Vickers Hardness In Swnt/al 2 O 3 Compositesmentioning

confidence: 78%

“…CNTs remain attached to the grains taking their shape and no pull-out is observed after intergranular fracture. SWNTs located mainly parallel to the fracture surface, implying few pull-outs, have also been observed in SWNT reinforced zirconia toughened alumina (ZTA) composites [25].…”

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confidence: 97%

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Improvement of Vickers hardness measurement on SWNT/Al2O3 composites consolidated by spark plasma sintering

Morales-Rodrı́guez

Gallardo-López

Fernández-Serrano

et al. 2014

Journal of the European Ceramic Society

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Dense alumina composites with different carbon nanotube content were prepared by colloidal processing and consolidated by Spark Plasma Sintering (SPS). Single-wall carbon nanotubes (SWNTs) were distributed at grain boundaries and also into agglomerates homogeneously dispersed. Carrying out Vickers hardness tests on the cross-section surfaces instead of top (or bottom) surfaces has shown a noticeable increase in the reliability of the hardness measurements. This improvement has been mainly attributed to the different morphology of carbon nanotube agglomerates, which however does not seem to affect the Vickers hardness value. Composites with lower SWNT content maintain the Vickers hardness of monolithic alumina, whereas it significantly decreases for the rest of compositions. The decreasing trend with increasing SWNT content has been explained by the presence of higher SWNT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Heterogeneous dispersion and distribution of CNTs in the ceramic matrix, poor chemical compatibility between CNTs and alumina hindering effective transfer load and the large differences in the scales of the matrix microstructure and the carbon nanotubes have been stated as main obstacles to transfer the desirable CNT mechanical properties to the brittle ceramic matrix [5,7,11,14,15]. Adequate dispersion of CNTs is very difficult owing to their tendency to form bundles in order to minimize their surface area.Although aqueous colloidal processing has been assessed as an efficient technique producing adequate dispersion of CNTs throughout ceramic matrix grain boundaries after sintering [18][19][20], the presence of agglomerates seems to be unavoidable.Recently, Poorteman et al [21] fabricated MWNT/alumina composites with low MWNT content (0.6 and 1.4 vol. %) by a colloidal processing route to optimize electrostatic

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Section: Microstructural Characterizationsupporting

confidence: 93%

Section: Evaluation Of Vickers Hardness In Swnt/al 2 O 3 Compositesmentioning

confidence: 78%

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Improvement of Vickers hardness measurement on SWNT/Al2O3 composites consolidated by spark plasma sintering

Morales-Rodrı́guez

Gallardo-López

Fernández-Serrano

et al. 2014

Journal of the European Ceramic Society

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“…The pulling-out of CNTs can disperse fracture energy. 43) Bocanegra-Bernal et al 27) achieved superior fracture toughness values (³8 MPa·m 1/2 ) with an efficient pull-out and bridging effect of MWCNTs with 0.1 wt % in ZTA ceramics. The micrographs and mechanical property data obtained in the present study suggest that improvement in the mechanical properties is strongly dependent on the amount and positioning of CNTs, as well as the strength of cohesion between the matrix and the CNTs.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…26),27) A study by Ahmad et al 26) on hot pressed Al 2 O 3 CNT composites found that additions of 2 and 5 wt % CNTs resulted in 0.5 and 3.4% reductions in density. Echeberria et al 27) studied the spark plasma sintered SWCNTs and MWCNTs reinforced zirconia-toughened alumina composites and reported relative density reduction with increasing well-dispersed CNTs content. In addition, An et al 28) reported that CNTs in alumina matrix decrease mass transportation during sintering and inhibit the densification process.…”

Section: Densification Behavior and Crystalline Phasesmentioning

confidence: 99%

Investigation of the microstructure, mechanical properties and cell viability of zirconia-toughened alumina composites reinforced with carbon nanotubes

Akin

2015

J. Ceram. Soc. Japan

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The addition of multi-wall carbon nanotubes (MWCNTs) to ceramic matrices can be utilized for special applications such as implant materials. In this study, zirconia toughened alumina (ZTA) composites having 10, 20 and 30 vol % yttria stabilized zirconia (YSZ) with additions of 0.5, 1, and 2 wt % MWCNTs were prepared by spark plasma sintering (SPS) at 1400°C under 40 MPa for 5 min. Systematic investigation of the effects of CNT reinforcement on densification behavior, microstructure, mechanical properties (Vickers microhardness, indentation fracture toughness, and flexural strength) and biocompatibility (cell viability) of ZTA composites was performed. The results indicated that the mechanical properties of CNT reinforced aluminabased composites are strongly dependent on the amount and position of nanotubes in the microstructure and the strength of the cohesion of matrix grains and the nanotubes. Composites with 30 vol % YSZ and 0.5 wt % CNTs exhibited the highest Vickers hardness, fracture toughness and flexure strength with values of ³18 GPa, 5.5 MPa·m 1/2 and 590 MPa, respectively. In addition, preliminary biocompatibility tests indicated that the composites showed no cytotoxicity to human osteoblast cells.

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SWCNTs versus MWCNTs as Reinforcement Agents in Zirconia‐and Alumina‐based Nanocomposites: Which One to Use

Bocanegra‐Bernal

Domínguez-Ríos

Garcia‐Reyes

et al. 2016

Advanced Ceramic Materials

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Hard and tough carbon nanotube-reinforced zirconia-toughened alumina composites prepared by spark plasma sintering

Cited by 68 publications

References 65 publications

Improvement of Vickers hardness measurement on SWNT/Al2O3 composites consolidated by spark plasma sintering

Improvement of Vickers hardness measurement on SWNT/Al2O3 composites consolidated by spark plasma sintering

Investigation of the microstructure, mechanical properties and cell viability of zirconia-toughened alumina composites reinforced with carbon nanotubes

SWCNTs versus MWCNTs as Reinforcement Agents in Zirconia‐and Alumina‐based Nanocomposites: Which One to Use

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