Reaction sintering of Al2O3 in the presence of the liquid phase

Kostić, E.; Bošković, S.; Kiss, S.

doi:10.1016/0272-8842(93)90055-v

Cited by 8 publications

(14 citation statements)

References 1 publication

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“…The composition and melting point of secondary phases seem to be in good agreement with predictions made from the Al 2 O 3 /Y 2 O 3 /SiO 2 phase diagram 22,23,25–27 . The compositions of the secondary phases detected surround the quasi‐ternary eutectic, which melts at 1660 K (Fig.…”

Section: Discussionsupporting

confidence: 83%

Effect of Silica on the Reactive Sintering of Polycrystalline Nd:YAG Ceramics

Maı̂tre

Sallé

Boulesteix

et al. 2008

Journal of the American Ceramic Society

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In the present work, the role of silica as sintering aids in the densification and the grain growth of yttrium aluminum garnet doped by neodymium (Nd:YAG) ceramics has been investigated. The samples were prepared by ball milling of pure oxides (Al2O3, Y2O3, Nd2O3, SiO2), shaped by cold uniaxial pressing, and sintered in vacuum between 1473 and 1973 K. After cooling, the specimens were annealed under air or vacuum. Their microstructure and the chemical composition of the secondary phases were examined using electron probe microanalysis, scanning electron microscopy, or transmission electron microscopy techniques. From these results, silica addition proved to be efficient on the densification kinetics between 1673 and 1873 K, especially when SiO2 content exceeds 0.05 wt%. Indeed, the solid‐state reaction between SiO2 and Nd:YAG particles in the vicinity of 1660 K leads to a liquid phase that adopts a eutectic composition in the Al2O3–Y2O3–SiO2 system. This phase enhances the densification by improving rearrangement of particles and mass transport at the grain boundaries. At a high temperature, liquid phase and silica were partially removed and some intergranular and intragranular inclusions of residual silica remained after cooling. The most promising thermal treatment consists of sintering Nd:YAG ceramics under vacuum at a high temperature (T≥1973 K) to reach fully dense pieces and to decrease the volume fraction of secondary phases (i.e., liquid phase or silica‐based phases). Finally, these conditions would allow to produce transparent YAG pieces due to their good homogeneity with regard to their microstructural properties (grain size, volume fraction of secondary phases).

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Section: Discussionsupporting

confidence: 83%

Effect of Silica on the Reactive Sintering of Polycrystalline Nd:YAG Ceramics

Maı̂tre

Sallé

Boulesteix

et al. 2008

Journal of the American Ceramic Society

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“…4 can be related to the formation of an intergranular liquid phase which enhances densification in doped-samples (increase on shrinkage rates). 16,59,[61][62][63] This liquid phase is transformed into a glassy phase when samples are cooled down, as observed in Fig. 10.…”

Section: Resultsmentioning

confidence: 98%

Sintering behaviour and microstructural evolution of ultrapure α-alumina containing low amounts of SiO2

Louet

Reverón

Fantozzi

2008

Journal of the European Ceramic Society

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“…The mechanical and microstructural properties of alumina are affected by the selection of additives [21,[30][31][32][33] and dopants [23,[34][35][36][37][38] used for sintering, which affect the grain size distribution and the phases formed in the grain boundaries.…”

Section: Effects Of Dopants On the Diffusivity In The Grain Boundariesmentioning

confidence: 99%

“…Liquid-phase sintering favors the formation of reaction products at considerably lower temperatures [16] than in solid-phase sintering. The kinetic parameters involved in the formation of reaction products allow for the mass transfer to be controlled by the precipitation solution process and by the phase distribution within the sintered samples [31]. The first stage of liquid-phase sintering -particle rearrangement -generally occurs at low sintering temperatures and is controlled by the viscosity and quantity of the liquid phase.…”

Section: Effects Of Liquid-phase Sinteringmentioning

confidence: 99%

Wear performance of alumina-based ceramics - a review of the influence of microstructure on erosive wear

et al. 2015

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Ceramic materials are of technical and commercial interest due to their chemical, mechanical and thermal performance, leading ceramics to meet many engineering requirements. Alumina (aluminum oxide) is one of the primary representatives of this class of materials because of its high fracture toughness, hardness and density, which enable its use in the production of highly critical parts. One such application involves protection against abrasion and erosion wear. The wear properties of a ceramic can be improved not only by controlling its material characteristics but also by controlling the fabrication process, which defines the material's microstructure. Many studies of the effects of the microstructure on these properties have been published. The objective of this study was to review the effects of the microstructure on the erosive wear resistance of alumina-based ceramics. Four factors that control the erosive wear of alumina were identified: (i) the effects of dopants on the diffusivity of the grain boundaries, (ii) the fabrication route, (iii) the sintering mechanisms and (iv) the alumina grain size. The published experimental results related to these topics are described and provide a clear understanding of the erosive wear of alumina.

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Reaction sintering of Al2O3 in the presence of the liquid phase

Cited by 8 publications

References 1 publication

Effect of Silica on the Reactive Sintering of Polycrystalline Nd:YAG Ceramics

Effect of Silica on the Reactive Sintering of Polycrystalline Nd:YAG Ceramics

Sintering behaviour and microstructural evolution of ultrapure α-alumina containing low amounts of SiO2

Wear performance of alumina-based ceramics - a review of the influence of microstructure on erosive wear

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