Processing optimisation and fracture behaviour of layered ceramic composites with highly compressive layers

Bermejo, Raúl; Baudı́n, Carmen; Moreno, Rodrigo; Llanes, L.; Sánchez-Herencia, Antonio Javier

doi:10.1016/j.compscitech.2006.10.010

Cited by 78 publications

(60 citation statements)

References 37 publications

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“…utilised. Details of the colloidal processing procedure may be found elsewhere [32]. The laminate plates, sintered at 1550 ºC for 2 hours in air, consist of a periodic, alternating stack of five thick ATZ layers, i.e.…”

Section: Introductionmentioning

confidence: 99%

Loading configuration effects on the strength reliability of alumina–zirconia multilayered ceramics

Bermejo¹,

Torres²,

Llanes³

2008

Composites Science and Technology

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Section: Introductionmentioning

confidence: 99%

Loading configuration effects on the strength reliability of alumina–zirconia multilayered ceramics

Bermejo¹,

Torres²,

Llanes³

2008

Composites Science and Technology

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“…The 1:10 ratio between the thicknesses of the layers allowed developing an intense compressive stress field in the external layers and a less intense tensile stress field in the intermediate layer. Considering that the implantation range of 22 Na positrons is about 200 m in ceramics, 20 and the diffusion length for the thermalized positrons even less of 200 m, 21 the thickness of 400 m for the outer layers was chosen to ensure that the annihilation of positrons was practically accomplished in the external Al 2 O 3 layers adjacent to the 22 Na positron source. Then, any contribution from annihilations in the inner layer and at the layer interface would be meaningless.…”

Section: Methodsmentioning

confidence: 99%

“…22 The starting powders, used to produce the samples, were ␣-Al 2 O 3 (Condea HPA 0.5, USA), and TZ-3YS (Tosoh, Japan), hereafter respectively denoted by A and TZ. A-A(TZ) X vol.% denoted the three-layer Al 2 O 3 -t-ZrO 2 samples.…”

Section: Methodsmentioning

confidence: 99%

“…Positron annihilation measurements at room temperature were made using a 22 Na positron source of ∼10 Ci sealed between two kapton foils (10 m thick) and sandwiched between the outer Al 2 O 3 surfaces of two identical samples. Positron lifetime spectra were recorded with a conventional fast-fast coincidence spectrometer equipped with two NE111 plastic scintillators.…”

Section: Methodsmentioning

confidence: 99%

“…[23][24][25] The shaping stage of the samples was preceded by the study of the casting kinetic of each suspension to obtain the thickness of the layers as a function of the casting time. 22 70 mm × 70 mm plates were slip cast on a plaster mould. Green bodies were pre-sintered at 900 • C for 1 h, cut into square samples ∼10 mm × 10 mm, and then sintered at 1500 • C for 2 h. The heating and cooling rates were of 5 • C min −1 .…”

Section: Methodsmentioning

confidence: 99%

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Characterization of residual compressive stresses in layered ceramics by positron annihilation spectroscopy

Parente¹,

Ortega²,

Savoini³

et al. 2012

Journal of the European Ceramic Society

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Abstract:Microstructural characterization of stress states of alumina layers subjected to residual compressive stresses was performed by positron annihilation spectroscopy (PAS). Al 2 O 3 -t-ZrO 2 three layered samples were appropriately designed and processed by sequential slip casting with symmetric structure. The zirconia contents inside the core layer were selected in order to generate compressive stresses of variable intensity in the outer Al 2 O 3 layers. PAS results highlighted a correlation between positron annihilation parameters and microstructural changes related to the generation of residual stresses.

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Nickel Sheets from Suspensions of the Metallic Powders in Water

2008

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Materials designs evolving nickel sheets combined with ceramics has applications in either electrical or structural applications. Examples can be taken from the fabrication of high J c -HTS (high temperature superconductors) tapes [1,2] or the high temperature SOFCs where the metallic nickel has been used because of good oxidation resistance and good match with the ceramic components (YBCO [3] and YSZ). On the other hand the same properties of nickel can be employed for thermo-mechanical purposes. The joining of alternate metallic and ceramics tapes permits the fabrication of materials with graceful failure and high work of fracture. [4][5][6] Processing of those laminated materials is a critical point as the final reinforcement depends strongly on the distribution of the layers. Colloidal processing techniques have proved to be an accurate method to develop laminated and graded microstructures in both ceramic-ceramic [7,8] and metal-ceramic [9] materials by a diverse techniques such as slip casting, tape casting, electrophoretic deposition or screen-printing. For any of those processing techniques, the rheology of the slurries is a critical parameter to be controlled in order process suitable samples. [10][11][12] But the use of metals together to ceramics requires of processing methods to force the microstructural developments or to favor the co-sintering and joining between tapes. In this sense, tape casting has been extensively used to produce substrates and pieces in a wide range of ceramic materials and microstructures [7,[13][14][15] with precise control of the thickness. Usually the dispersion media has been an organic liquid due to their compatibility with the most common binders and plasticizers, [16] but environmental and economical reasons are promoting the employment of water as the dispersion media. [6,13,15] Aqueous slurries for tape casting implies an increment in the solid content of the slurries as a key issue to fabricate handily green tapes. [12,13] In this sense, previous works employed electrochemical [17] and rheological [11,18] investigations to optimize slurries of metallic nickel in water up to solid contents of 40 vol%. Dense and porous material has been later fabricated starting with those optimized slurries by colloidal techniques employed in ceramic processing. [17][18][19] In this paper the fabrication of nickel dense sheets has been faced by the employment of aqueous based tape casting. Previous studies demonstrated that better stability of Ni powders in water was reached when assuring a pH high enough to prevent dissolution (Ni 2+ ) and hydroxylation (through NiO(OH) and Ni(OH) 2 species), so that pH must be higher than 9. Furthermore, a maximum zeta potential of about -50 mV is reached when adding 1 wt% polyelectrolyte at a pH = 10. [17] Well-dispersed suspensions of nickel in water prepared under those conditions were rheologically characterized with different binder contents. The flow curve measured in the CR mode for suspensions prepared to solids loadings of 31 vol % and 40 v...

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Processing optimisation and fracture behaviour of layered ceramic composites with highly compressive layers

Cited by 78 publications

References 37 publications

Loading configuration effects on the strength reliability of alumina–zirconia multilayered ceramics

Loading configuration effects on the strength reliability of alumina–zirconia multilayered ceramics

Characterization of residual compressive stresses in layered ceramics by positron annihilation spectroscopy

Nickel Sheets from Suspensions of the Metallic Powders in Water

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