Flash sintering of a three‐phase alumina, spinel, and yttria‐stabilized zirconia composite

Kok, David; Jha, Shikhar Krishn; Raj, Rishi; Mecartney, Martha L.

doi:10.1111/jace.14818

Cited by 45 publications

(37 citation statements)

References 30 publications

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“…Evidence for the formation of phases far from equilibrium in flash experiments, continues to grow. For example, very recently, Kok et al have shown the evolution of a high alumina phase of spinel, which is outside the equilibrium regime of the phase diagram; this reaction was shown to occur within 2 or 3 seconds …”

Section: Introductionmentioning

confidence: 99%

Reactive flash sintering: MgO and α‐Al₂O₃ transform and sinter into single‐phase polycrystals of MgAl₂O₄

et al. 2018

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We show that flash experiments with three phase mixed-powders of yttria-stabilized zirconia (8YSZ), MgO, and α-Al 2 O 3 not only produce polycrystals of high density, but also the transformation of magnesia and alumina into single-phase spinel. The presence of zirconia facilitates the onset of the flash. The sintering experiments in the laboratory were extended to live experiments at the National Synchrotron Light Source II at Brookhaven National Laboratory in order to measure the time-dependent evolution of single-phase spinel. The phase transformation occurred in <3 seconds during Stage II. Later, during Stage III the cubic zirconia transformed partly into the monoclinic phase, which reverted back to the cubic phase when the flash was extinguished by turning off the current to the specimen. The results underpin a recent report on the synthesis of single-phase bismuth ferrite from constituent oxides in reactive flash experiments, raising the specter of flash as a method for synthesis as well as sintering of complex oxide ceramics. The role of zirconia in catalyzing the flash in the present study is discussed.

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Section: Introductionmentioning

confidence: 99%

Reactive flash sintering: MgO and α‐Al₂O₃ transform and sinter into single‐phase polycrystals of MgAl₂O₄

et al. 2018

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“…However, most studies on the flash sintering have concentrated on single phase ceramic materials. Only a few investigations have been reported on the flash sintering of the ceramic composites …”

Section: Introductionmentioning

confidence: 99%

“…Only a few investigations have been reported on the flash sintering of the ceramic composites. [19][20][21] Yttria stabilized zirconia (YSZ) ceramics have been widely used in materials industry due to their high toughness, hardness, creep resistance, and ionic conductivity. Incorporation of a second phase in a ceramic matrix is known to improve their properties.…”

Section: Introductionmentioning

confidence: 99%

Flash sintering of 3YSZ/Al₂O₃‐platelet composites

Jia

et al. 2019

J Am Ceram Soc

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Preparation of 3YSZ/Al 2 O 3 -platelet composites always requires high temperature, long duration, and/or high pressure. Herein, 3YSZ/Al 2 O 3 -platelet composites are prepared at low temperature of 492°C-645°C in 30 seconds by flash sintering under the electric field of 300-800 V/cm. The influence of electric field and current limit on the densification and grain growth of composites is investigated. The onset temperature for flash sintering is determined by electric field, which is decreased with increasing the electric field. Under the constant electric field, the current limit has a great effect on the density and grain size of composite. The flash-sintered 3YSZ/ Al 2 O 3 -platelet composites exhibit relatively high hardness and elastic modulus. Both Joule heating and defects generation are proposed to be responsible for the rapid densification in flash sintering. This work demonstrates the feasibility of employing the flash sintering to prepare ceramic composites with fine grain size. K E Y W O R D Sceramic matrix composites, defects, densification, flash sintering, grain growth

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“…Zirconia (ZrO 2 ) continuous fibers are the outstanding ultra‐high temperature thermal insulators and reinforced materials due to the characteristics of high melting point (2715°C), low thermal conductivity, and excellent mechanical strength . Generally, ZrO 2 fibers having the lengths larger than 1.0 m are defined as the continuous fibers .…”

Section: Introductionmentioning

confidence: 99%

Effect of high‐pressure vapor pretreatment on the microstructure evolution and tensile strength of zirconia fibers

et al. 2019

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High-strength zirconia (ZrO 2 ) continuous fibers, which are potential candidates as ultra-high temperature thermal insulators and reinforced materials, are typically fabricated by dry spinning an organozirconium precursor. However, the uncontrolled decomposition of organozirconium precursor usually occurs upon heat treatment that breaks the continuous fibers into pieces, resulting in the loss of tensile strength.Herein, in this contribution, we aimed to maintain the integrity of ZrO 2 precursor fibers during heat treatment. For this purpose, novel high-pressure vapor (HPV) pretreatment of ZrO 2 precursor fiber was introduced. The HPV pretreatment is considered to be efficient for the removal of the organics in precursor, promoting the formation of amorphous structures of Zr(OH) 4 and Zr(OH) 3 HCO 3 . Combining the studies of microstructures and tensile strengths, it was found that the amorphous structures played roles of cross-linking points, keeping the fibers integrity during the followed heat treatment. After HPV pretreatment, the high-strength ZrO 2 continuous fibers would be obtained by direct sintering in air without any atmosphere which substantially lowered the cost. The tensile strengths of sintered ZrO 2 continuous fibers pretreated by an optimized HPV procedure could reach up to as high as 1.299 GPa. The HPV pretreatment method provides a high-efficiency, low-cost technique for preparing high-quality ceramic fibers. K E Y W O R D Shigh-pressure vapor pretreatment, polyaceticzirconium, tensile strength, transition process

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Flash sintering of a three‐phase alumina, spinel, and yttria‐stabilized zirconia composite

Cited by 45 publications

References 30 publications

Reactive flash sintering: MgO and α‐Al₂O₃ transform and sinter into single‐phase polycrystals of MgAl₂O₄

Reactive flash sintering: MgO and α‐Al₂O₃ transform and sinter into single‐phase polycrystals of MgAl₂O₄

Flash sintering of 3YSZ/Al₂O₃‐platelet composites

Effect of high‐pressure vapor pretreatment on the microstructure evolution and tensile strength of zirconia fibers

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Flash sintering of a three‐phase alumina, spinel, and yttria‐stabilized zirconia composite

Cited by 45 publications

References 30 publications

Reactive flash sintering: MgO and α‐Al2O3 transform and sinter into single‐phase polycrystals of MgAl2O4

Reactive flash sintering: MgO and α‐Al2O3 transform and sinter into single‐phase polycrystals of MgAl2O4

Flash sintering of 3YSZ/Al2O3‐platelet composites

Effect of high‐pressure vapor pretreatment on the microstructure evolution and tensile strength of zirconia fibers

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Product

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Reactive flash sintering: MgO and α‐Al₂O₃ transform and sinter into single‐phase polycrystals of MgAl₂O₄

Reactive flash sintering: MgO and α‐Al₂O₃ transform and sinter into single‐phase polycrystals of MgAl₂O₄

Flash sintering of 3YSZ/Al₂O₃‐platelet composites