Direct Synthesis of Metastable Nanocrystalline ZrW<sub>2</sub>O<sub>8</sub> by a Melt-Quenching Method

Mancheva, M.; Iordanova, R.; Dimitriev, Y.; Petrov, Κ.; Avdeev, G.

doi:10.1021/jp074870f

Cited by 8 publications

(5 citation statements)

References 22 publications

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“…The melt quenching method is well known for the preparation of glassy or metastable phases and also for the design of the so-called glass ceramics [12][13][14]. The results reported by Morito et al [15] and our results published recently [16] showed that this method was appropriate for the preparation of cubic ZrW 2 O 8 and metastable orthorhombic (c) ZrW 2 O 8 . These results motivated us to extend the melt quenching method to the preparation of other phases with the same crystallographic structure.…”

Section: Introductionmentioning

confidence: 63%

Synthesis of cubic ZrWMoO8 by a melt quenching method

Mancheva

Iordanova

Dimitriev

et al. 2009

Journal of Non-Crystalline Solids

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Section: Introductionmentioning

confidence: 63%

Synthesis of cubic ZrWMoO8 by a melt quenching method

Mancheva

Iordanova

Dimitriev

et al. 2009

Journal of Non-Crystalline Solids

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“…The small peak at about 2 θ = 24.5° was not from the α‐phase ZrW 2 O 8 . Perhaps it was caused by the impurity (possible WO 3 ).…”

Section: Resultsmentioning

confidence: 99%

Zirconium tungstate/bismaleimide composite

Chen¹,

Chen

2011

Polymers for Advanced Techs

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The residual stress that arises from processing and the mismatch of coefficient of the thermal expansion (CTE) between polymer and carbon fiber (or metal) could cause a crack initiation and de‐lamination in the aircraft structural applications. In this study, bismaleimide composites with zirconium tungstate (−8.8 ppm/K) were successfully fabricated. A synergetic effect led to a significant improvement of the thermal stability of the composites due to the formation of the integrated structure in the zirconium tungstate (ZrW2O8)/Matrimid 5292 (Huntsman, the Woodlands, TX) composite at high temperature, which prevented and/or slowed the escape of the thermal decomposition by‐products. The addition of zirconium tungstate into the Matrimid 5292 could also increase the storage modulus while keeping the glass transition temperature unchanged. The CTE of a 20 vol.% ZrW2O8/Matrimid 5292composite material can be reduced by 40% compared with that of the pure Matrimid 5292. The extent of reduction in the CTE is much greater than predicted from the rule of mixture. Micromechanical modeling shows that the Christensen model and the Schapery upper limit model gave a good prediction of CTEs for ZrW2O8/Matrimid 5292 composite. Published 2011. This article is a US Government work and is in the public domain in the USA.

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“…19,22 This phase transition is completely reversible, and the α-phase is restored upon cooling the material below the transition temperature. Zirconium tungstate begins decomposing into WO 3 and ZrO 2 after prolonged heating at 600 °C, 23 thus limiting the processing temperature for composite preparation. In addition, amorphization of the cubic α-phase is found to occur when high pressures are applied.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Reported CTE values for this material vary between −8.7 ppm/°C and −9.1 ppm/°C up to about 160 °C. , If heated above this temperature, it undergoes a phase transition to a slightly disordered state (the cubic β-phase) that causes the CTE to increase, although the material still has a negative CTE (−4.9 ppm/°C). , This phase transition is completely reversible, and the α-phase is restored upon cooling the material below the transition temperature. Zirconium tungstate begins decomposing into WO 3 and ZrO 2 after prolonged heating at 600 °C, thus limiting the processing temperature for composite preparation. In addition, amorphization of the cubic α-phase is found to occur when high pressures are applied.…”

Section: Introductionmentioning

confidence: 99%

Copper-Based Conductive Composites with Tailored Thermal Expansion

Gaspera

Tucker

Star

et al. 2013

ACS Appl. Mater. Interfaces

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We have devised a moderate temperature hot-pressing route for preparing metal-matrix composites which possess tunable thermal expansion coefficients in combination with high electrical and thermal conductivities. The composites are based on incorporating ZrW2O8, a material with a negative coefficient of thermal expansion (CTE), within a continuous copper matrix. The ZrW2O8 enables us to tune the CTE in a predictable manner, while the copper phase is responsible for the electrical and thermal conductivity properties. An important consideration in the processing of these materials is to avoid the decomposition of the ZrW2O8 phase. This is accomplished by using relatively mild hot-pressing conditions of 500 °C for 1 h at 40 MPa. To ensure that these conditions enable sintering of the copper, we developed a synthesis route for the preparation of Cu nanoparticles (NPs) based on the reduction of a common copper salt in aqueous solution in the presence of a size control agent. Upon hot pressing these nanoparticles at 500 °C, we are able to achieve 92-93% of the theoretical density of copper. The resulting materials exhibit a CTE which can be tuned between the value of pure copper (16.5 ppm/°C) and less than 1 ppm/°C. Thus, by adjusting the relative amount of the two components, the properties of the composite can be designed so that a material with high electrical conductivity and a CTE that matches the relatively low CTE values of semiconductor or thermoelectric materials can be achieved. This unique combination of electrical and thermal properties enables these Cu-based metal-matrix composites to be used as electrical contacts to a variety of semiconductor and thermoelectric devices which offer stable operation under thermal cycling conditions.

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Direct Synthesis of Metastable Nanocrystalline ZrW₂O₈ by a Melt-Quenching Method

Cited by 8 publications

References 22 publications

Synthesis of cubic ZrWMoO8 by a melt quenching method

Synthesis of cubic ZrWMoO8 by a melt quenching method

Zirconium tungstate/bismaleimide composite

Copper-Based Conductive Composites with Tailored Thermal Expansion

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Direct Synthesis of Metastable Nanocrystalline ZrW2O8 by a Melt-Quenching Method

Cited by 8 publications

References 22 publications

Synthesis of cubic ZrWMoO8 by a melt quenching method

Synthesis of cubic ZrWMoO8 by a melt quenching method

Zirconium tungstate/bismaleimide composite

Copper-Based Conductive Composites with Tailored Thermal Expansion

Contact Info

Product

Resources

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Direct Synthesis of Metastable Nanocrystalline ZrW₂O₈ by a Melt-Quenching Method