Sintering of ZrO&lt;sub&gt;2&lt;/sub&gt; Toughened Mullite Ceramics and Its Microstructure

Shiga, Hiroshi; Ismail, M. G. M. U.; Katayama, Keiichi

doi:10.2109/jcersj.99.798

Cited by 9 publications

(2 citation statements)

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“…Yoor and Chen [23] produced ZrO 2 -mullite ceramics from commercial ZrO 2 and mullite starting materials prepared by co-precipitation of TEOS and aluminum nitrate non-hydrate solution. Shiga et al [24] used the solgel methods to prepare ZrO 2 -mullite composites. Nicolás and co-workers [25] prepared mullitezirconia composites using reaction sintering of alumina and zircon and direct sintering of mullitezirconia grains.…”

Section: Introductionmentioning

confidence: 99%

Properties of Mullite-Zirconia Composites Prepared through Reaction Sintering Kaolin, α-Al2O3, and ZrO2

Sahnoune

Saheb

Goeuriot

2010

AMR

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Mullite–zirconia composites were synthesized through reaction sintering Algerian kaolin, α-Al2O3, and ZrO2. Phases present and their transformations were characterized using x-ray diffraction. Quantitative phase analysis was performed following the Rietveld method. Hardness and fracture toughness were measured by Vickers indentation. The flexural strength was measured using a Universal Testing Machine. It was found that the microstructure of samples sintered for 2 hours at 1600°C was composed of mullite grains which have whiskers’ shape and ZrO2 particles. In the composite containing 16 wt.% ZrO2, the ratio of tetragonal zirconia transformed to monoclinic zirconia was relatively small and did not exceed 18%. However, in the composite containing 32 wt.% ZrO2 around 75% of the tetragonal structure changed to monoclinic structure. Also, it was found that the increase of ZrO2 content from 0 to 32 wt.% decreased the microhardness of the composites from 14 to 10.8 GPa. However, the increase of ZrO2 content from 0 to 24wt.% increased the flexural strength of the composites from 142 to 390 MPa then decreased it with further increase of ZrO2 content. The fracture toughness increased from 1.8 to 2.9 MPa.m1/2 with the increase of ZrO2 content from 0 to 32 wt.%; and the rate of the increase decreased at higher fractions of ZrO2 content. The average linear coefficient of thermal expansion (within the range 50 to 1450°C) for samples containing 0 and 16 wt.% ZrO2 sintered at 1600°C for 2 hours was 4.7 x10-6 K-1 and 5.2 x 10-6 K-1 respectively.

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Section: Introductionmentioning

confidence: 99%

Properties of Mullite-Zirconia Composites Prepared through Reaction Sintering Kaolin, α-Al2O3, and ZrO2

Sahnoune

Saheb

Goeuriot

2010

AMR

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“…The MZz multicomposites exhibit excellent corrosion and thermal shock resistances and enhanced mechanical properties [13,14]. These materials can be obtained by different processes [15][16][17][18][19]. The content and structure of phases present in these materials may be related to the phase content of the raw materials and to the eventual zircon dissociation and monoclinic to tetragonal martensitic zirconia transformation [20].…”

Section: Introductionmentioning

confidence: 99%

A short and long range study of mullite–zirconia–zircon composites

et al. 2010

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In the field of refractory materials, ceramics containing mullite-zirconia are the basis of those most used in the industry of glass and steel. It is known that the addition of zircon improves the behavior of the refractory used in service. Knowing that some mullite-zirconia composites properties as fracture strength and the elastic modulus E are associated with the material microstructure integrity, the eventual thermal decomposition of zircon into zirconia and silica could seriously alter the material elastic properties. In this paper the phase content of a series of mullite-zirconia-zircon (3Al 2 O 3 .2SiO 2 -ZrO 2 -ZrSiO 4 ) composites is determined at atomic level via perturbed angular correlations (PAC) and compared with that derived from the long range X-ray diffraction technique. PAC results on the asprepared materials indicate that all nominal zircon is present and that it involves two types of nanoconfigurations, one of them describing aperiodic regions. The

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