Effects of Nb2O5 addition on the sinterability, microstructure and mechanical behaviour of ZTM-A12O3

Jin, Xiaoning; Gao, Lian; Chen, Y.R.; Yuan, Quan

doi:10.1016/s0955-2219(00)00108-4

Cited by 5 publications

(7 citation statements)

References 7 publications

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“…Because of its high melting point, low thermal expansion, good chemical stability, excellent creep resistance and high strength at high temperature, dense mullite (3Al 2 O 3 -2SiO 2 ) is recognised as one of the most promising engineering materials for applications at elevated temperature. 1,2 One of the methods used for preparation of mullite is reaction sintering of aluminasilica, kaolin-alumina mixtures or solid state sintering of fine crystalline mullite powders. Fine crystalline mullite powder compacts require high temperatures (.1600uC) to sinter to high density.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, it is usually reinforced with particles or fibres (whiskers) to produce composites with superior properties. 1,[7][8][9][10][11][12] A well known process to improve fracture toughness 1,2,13-16 is phase transformation, under applied pressure, from tetragonal to monoclinic in zirconia particles. This stress induced phase transformation is accompanied by a volume expansion (y4%) and shear deformation (y6%).…”

Section: Introductionmentioning

confidence: 99%

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Phase transformation and sintering behaviour of mullite and mullite–zirconia composite materials

Sahnoune

Belhouchet

Saheb

et al. 2011

Advances in Applied Ceramics

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Mullite is one of the most promising engineering materials for applications at elevated temperatures, but has poor mechanical properties at ambient temperature; therefore, it is usually reinforced with particles, fibres or whiskers to improve its properties. Among particles added to mullite are ZrO 2 particles which improve its fracture toughness through the well known process of phase transformation from tetragonal to monoclinic in zirconia particles. The aim of the present work is to explore the utilisation of Algerian kaolin, a-Al 2 O 3 and ZrO 2 to synthesise mullite-ZrO 2 composites through reaction sintering and investigate phase transformation and sintering behaviour of the composites. The raw materials were mixed through planetary ball milling followed by attrition milling. Compacted samples were sintered at temperatures between 1100 and 1600uC for 2 h. The bulk density was measured by the water immersion method. X-ray diffraction (Rietveld method) was used to characterise phases present in the sintered samples. It was found that the zirconia phase retained its tetragonal structure with the addition of up to 16% zirconia. The formation of primary mullite in all samples was complete at 1250uC. The cristobalite started to form at 1150uC, and disappeared at 1300uC in the samples of mullite, and at 1250uC when ZrO 2 was added. The zircon compound ZrSiO 4 started to form at 1250uC and completely disappeared at 1400uC. The increase in ZrO 2 ratio promoted the formation of grains with spherical shape.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase transformation and sintering behaviour of mullite and mullite–zirconia composite materials

Sahnoune

Belhouchet

Saheb

et al. 2011

Advances in Applied Ceramics

View full text Add to dashboard Cite

show abstract

“…Mullite is recognized as one of the most promising engineering materials for applications at elevated temperatures because of its high melting point, low thermal expansion, good chemical stability, excellent creep resistance and high strength at high temperatures [1,2]. However, applications of mullite were limited because of its poor properties at ambient temperature.…”

Section: Introductionmentioning

confidence: 99%

“…However, applications of mullite were limited because of its poor properties at ambient temperature. One way to improve the properties of mullite is to reinforce it by addition of particles, fibers or whiskers to produce composites with superior properties [1,[3][4][5][6][7][8]. Also, a well-known process to improve fracture toughness [1][2][9][10][11][12] is phase transformation, under applied pressure, from tetragonal to monoclinic in zirconia particles.…”

Section: Introductionmentioning

confidence: 99%

“…One way to improve the properties of mullite is to reinforce it by addition of particles, fibers or whiskers to produce composites with superior properties [1,[3][4][5][6][7][8]. Also, a well-known process to improve fracture toughness [1][2][9][10][11][12] is phase transformation, under applied pressure, from tetragonal to monoclinic in zirconia particles. This stress-induced phase transformation is accompanied by a volume expansion (~4%) and shear deformation (~6%) [2,13].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Sintering Behavior of Mullite-Zirconia Composites

Sahnoune

Saheb

Chegaar

et al. 2010

MSF

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In the present work, the structure and sintering behaviour of mullite-zirconia composites were investigated. The composites were prepared by reaction sintering of Algerian kaolin, α-Al2O3, and stabilized zirconia (3Y-TZP). The raw materials were wet ball milled in a planetary ball mill followed by attrition. The green samples shaped using a uniaxial press were sintered between 1100°C and 1600°C for 2 hours. The density was measured by the water immersion method. Phases present and change of the average crystallite size of the mullite phase as a function of sintering temperature and ZrO2 content were characterized through X-ray diffraction. Mulite grains had whiskers' shape; however, the increase of ZrO2 content changed the morphology of grains to near spherical shape. The microstructure of the samples revealed uniform distribution of ZrO2 particles; also, aluminium was uniformly distributed on all grains exception on zirconia grains. At least a relative density of 95 % was achieved for all samples at a relatively lower sintering temperature of 1500°C. In composites containing up to 16 wt. % ZrO2, the zirconia phase retained its tetragonal structure and the transformed part did not exceed 3 %. However, with the addition of 32 wt. % ZrO2 around 66 % of the tetragonal structure changed to monoclinic structure.

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Zirconia–mullite materials prepared from semi-colloidal route derived precursors

Maitra¹,

Rahaman²,

Sarkar³

et al. 2006

Ceramics International

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Effects of Nb2O5 addition on the sinterability, microstructure and mechanical behaviour of ZTM-A12O3

Cited by 5 publications

References 7 publications

Phase transformation and sintering behaviour of mullite and mullite–zirconia composite materials

Phase transformation and sintering behaviour of mullite and mullite–zirconia composite materials

Microstructure and Sintering Behavior of Mullite-Zirconia Composites

Zirconia–mullite materials prepared from semi-colloidal route derived precursors

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