Direct comparison between hot pressing and electric field-assisted sintering of submicron alumina

Langer, Jochen; Hoffmann, Michael J.; Guillon, Olivier

doi:10.1016/j.actamat.2009.07.043

Cited by 163 publications

(119 citation statements)

References 31 publications

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“…Therefore, according to equations (2), (3) and (4), the stress exponent n can be calculated if grain size and temperature are kept constant, using the following relation [29]:…”

Section: Resultsmentioning

confidence: 99%

Unveiling the mechanisms of cold sintering of ZnO at 250 °C by varying applied stress and characterizing grain boundaries by Kelvin Probe Force Microscopy

et al. 2018

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The sintering behavior of nanocrystalline ZnO was investigated at only 250 °C. Densification was achieved by the combined effect of uniaxial pressure and the addition of water both in a Field Assisted Sintering Technology/Spark Plasma Sintering apparatus and a warm hand press with a heater holder. The final pure ZnO materials present high densities (> 90 % theoretical density) with nano-grain sizes. By measuring the shrinkage rate as a function of applied stress it was possible to identify the stress exponent related to the densification process. A value larger than one points to non-linear relationship going beyond single solid-state diffusion or liquid phase sintering. Only a low amount of water (1.7 wt.%) was needed since the process is dictated by the adsorption on the surface of the ZnO particles. Part of the adsorbed water dissociates into H + and OH -ions, which diffuse into the ZnO crystal structure, generating grain boundaries/interfaces with high defect chemistry. As characterized by Kelvin Probe Force Microscopy, and supported by impedance spectroscopy, this highly defective grain boundary area presents much higher surface energy than the bulk. This highly defective grain boundary area with high potential reduces the activation energy of the atomic diffusion, leading to sinter the compound at low temperature.

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“…Therefore, according to equations (2), (3) and (4), the stress exponent n can be calculated if grain size and temperature are kept constant, using the following relation [29]:…”

Section: Resultsmentioning

confidence: 99%

Unveiling the mechanisms of cold sintering of ZnO at 250 °C by varying applied stress and characterizing grain boundaries by Kelvin Probe Force Microscopy

et al. 2018

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“…Under equilibrium conditions, the MAX-phase grains appear as hexagonal plates in which the hexagonal surfaces are parallel to the (0 0 0 1) planes [25]. However, SPS is a nonequilibium process due to use of pulsed electrical current combined with rapid heating and the application of pressure to achieve rapid sintering [26]. In this case, the growth of Ti 2 AlN nanowhiskers in TiAl occurs preferentially along the (0 0 0 1) planes, but is also influenced by other factors, such as the concentration gradient of TiN, grain boundaries and dislocations in TiAl.…”

Section: Nanowhisker Formation Mechanismmentioning

confidence: 99%

Microstructural evolution during high-temperature oxidation of spark plasma sintered Ti2AlN ceramics

et al. 2012

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“…The final grain size can be several times larger than the initial particle size and comparable sintering trajectories have been measured for several oxides densified by FAST/SPS and HP. [30][31][32] This effect should be particularly marked for agglomerated nanopowders. A finer starting particle size may even lead to a larger grain size than a coarser one at full density.…”

Section: Mechanical Effectsmentioning

confidence: 99%

Field‐Assisted Sintering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments

et al. 2014

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Field-assisted sintering technology/Spark plasma sintering is a low voltage, direct current (DC) pulsed current activated, pressure-assisted sintering, and synthesis technique, which has been widely applied for materials processing in the recent years. After a description of its working principles and historical background, mechanical, thermal, electrical effects in FAST/SPS are presented along with the role of atmosphere. A selection of successful materials development including refractory materials, nanocrystalline functional ceramics, graded, and non-equilibrium materials is then discussed. Finally, technological aspects (advanced tool concepts, temperature measurement, finite element simulations) are covered.

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Direct comparison between hot pressing and electric field-assisted sintering of submicron alumina

Cited by 163 publications

References 31 publications

Unveiling the mechanisms of cold sintering of ZnO at 250 °C by varying applied stress and characterizing grain boundaries by Kelvin Probe Force Microscopy

Unveiling the mechanisms of cold sintering of ZnO at 250 °C by varying applied stress and characterizing grain boundaries by Kelvin Probe Force Microscopy

Microstructural evolution during high-temperature oxidation of spark plasma sintered Ti2AlN ceramics

Field‐Assisted Sintering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments

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