Design of Desintering in Tin Dioxide Nanoparticles

Chang, Chi-Hsiu; Rufner, Jorgen F.; Benthem, Klaus van; Castro, Ricardo H. R.

doi:10.1021/cm402330u

Cited by 18 publications

(23 citation statements)

References 25 publications

(52 reference statements)

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“…Swelling in LaFeO 3 ‐type ceramics was attributed to phase equilibria that led to oxygen gas releases and pore expansion, together with the presence of a liquid phase that also promoted exaggerated grain growth . The role of additives should also be taken into account: dopant redistribution during sintering can induce de‐densification due to a change in oxidation state and interfacial chemistry . In the same manner, when cobalt is used as a sintering aid in (Bi 0.5 Na 0.5 )TiO 3 piezoelectric ceramics, its valence state changes during heating to produce O 2 releases.…”

Section: Introductionmentioning

confidence: 99%

“…[16][17][18] The role of additives should also be taken into account: dopant redistribution during sintering can induce de-densification due to a change in oxidation state and interfacial chemistry. 32 In the same manner, when cobalt is used as a sintering aid in (Bi 0.5 Na 0.5 )TiO 3 piezoelectric ceramics, its valence state changes during heating to produce O 2 releases. The gas is trapped in the closing pores, which inducing swelling.…”

Section: Introductionmentioning

confidence: 99%

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De‐densification mechanisms of yttria‐doped cerium oxide during sintering in a reducing atmosphere

2018

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The presence of residual carbon in oxides in which the valence state can change during sintering may lead to de‐densification or swelling phenomena during the last stage of sintering. This was demonstrated by sintering a Ce0.85Y0.15O2‐x powder compact with or without added graphite carbon in a reducing atmosphere (Ar/5 vol.% H2) at 1450°C. The shrinkage behavior was studied with a dilatometer combined with an oxygen probe and a gas chromatograph to analyze the composition of the released gases. Oxide reduction during sintering leads to a significant release of oxygen. This oxygen can react with carbon to form gaseous species such as CO. These gases can be released during the second stage of sintering, that is, when the porosity is still open, but they can be trapped in the closing pores during the final stage of sintering. This causes the pressure to increase in the pores, resulting in irreversible swelling, cracking and eventually pellet fracture.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

De‐densification mechanisms of yttria‐doped cerium oxide during sintering in a reducing atmosphere

2018

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“…Temperature has been recently reported to affect the driving force for sintering in doped systems by ion migration. 33 In our case, we see that the surface redox state can also be affected by temperature and hence affect densification driving forces.…”

Section: E Dihedral Angles On Thermodynamics Of Sinteringmentioning

confidence: 57%

“…All details of analysis were shown in our previous work. 33 Note that it is particularly difficult to define if the contact angle has reached its equilibrium state (dihedral angle) or not. Ideally, the measurement of angles at different temperatures would allow a better definition if the angle is still changing or not (determining the dihedral angle).…”

Section: E Dihedral Angles On Thermodynamics Of Sinteringmentioning

confidence: 99%

Surface and grain boundary energies of tin dioxide at low and high temperatures and effects on densification behavior

Chang

Castro

2014

J. Mater. Res.

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This work presents experimental data on the surface and grain boundary energies of tin dioxide nanoparticles at room temperature and high temperature conditions (quenched from 1300°C), and a discussion of impacts on the fundamental understanding of the nondensification mechanism of SnO 2 during sintering. The results were obtained using a combination of water adsorption microcalorimetry, high-temperature oxide melt drop solution calorimetry, and scanning electron transmission microscopy. At room temperature, the average surface and grain boundary energies of anhydrous SnO 2 were 1.20 6 0.02 and 0.71 6 0.08 J m À2 , respectively. At high temperature, SnO 2 showed a surface energy of 0.94 6 0.03 J m À2 . This remarkable decrease was attributed to the lower oxygen pressure and was associated with a decrease in contact angle during sintering. This observation indicates a moderate but significant thermodynamic reason behind nondensification behavior of SnO 2 in addition to common kinetic descriptions: high sintering temperatures and atmospheres cause smaller dihedral angles that decrease sintering stresses.

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“…Acquired spectrum images were decomposed into eigenspectra with assigned eigenvalues. EELS spectra were subsequently reconstructed by using only statistically relevant principal constituents [28,29].…”

Section: Chemical Composition Characterizationmentioning

confidence: 99%

Metal/ceramic interface structures and segregation behavior in aluminum-based composites

Zhang

Rufner

et al. 2015

Acta Materialia

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a b s t r a c tTrimodal Al alloy (AA) matrix composites consisting of ultrafine-grained (UFG) and coarse-grained (CG) Al phases and micron-sized B 4 C ceramic reinforcement particles exhibit combinations of strength and ductility that render them useful for potential applications in the aerospace, defense and automotive industries. Tailoring of microstructures with specific mechanical properties requires a detailed understanding of interfacial structures to enable strong interface bonding between ceramic reinforcement and metal matrix, and thereby allow for effective load transfer. Trimodal AA metal matrix composites typically show three characteristics that are noteworthy: nanocrystalline grains in the vicinity of the B 4 C reinforcement particles; Mg segregation at AA/B 4 C interfaces; and the presence of amorphous interfacial layers separating nanocrystalline grains from B 4 C particles. Interestingly, however, fundamental information related to the mechanisms responsible for these characteristics as well as information on local compositions and phases are absent in the current literature. In this study, we use high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy, and precession assisted electron diffraction to gain fundamental insight into the mechanisms that affect the characteristics of AA/B 4 C interfaces. Specifically, we determined interfacial structures, local composition and spatial distribution of the interfacial constituents. Near atomic resolution characterization revealed amorphous multilayers and a nanocrystalline region between Al phase and B 4 C reinforcement particles. The amorphous layers consist of nonstoichiometric Al x O y , while the nanocrystalline region is comprised of MgO nanograins. The experimental results are discussed in terms of the possible underlying mechanisms at AA/B 4 C interfaces.

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Design of Desintering in Tin Dioxide Nanoparticles

Cited by 18 publications

References 25 publications

De‐densification mechanisms of yttria‐doped cerium oxide during sintering in a reducing atmosphere

De‐densification mechanisms of yttria‐doped cerium oxide during sintering in a reducing atmosphere

Surface and grain boundary energies of tin dioxide at low and high temperatures and effects on densification behavior

Metal/ceramic interface structures and segregation behavior in aluminum-based composites

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