Microstructural evolution and mechanism of grain growth in magnesia ceramics prepared by high pressure and temperature with ultra-high heating rate

The technique of combustion reaction and quick pressing was adopted to prepare dense nanocrystalline ceramics. The densification process of magnesia compact with a particle size of 100 nm was investigated, under the applied pressure of up to 170 MPa, and the temperature of 1740–2080 K with ultra-high heating rate of above 1700 K/min. As a result, pure magnesia ceramics with a relative density of 98.8% and an average grain size of 120 nm was obtained at 1740 K and 170 MPa, while the ones with decreased relative density and increased grain size were produced under the increasing temperature and the identical pressure conditions. The results indicated that grain growth of the nanocrystalline magnesia was effectively restrained by the combined effect of the ultra-high heating rate and the high pressure. Moreover, under the particular sintering conditions, there existed an appropriate temperature range for the preparation of dense nanocrystalline magnesia, and the excessive temperature would not only exaggerate grain growth but also impede densification.

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Investigations on High Heating Rate and Precision Calibration of the Thermoelectric Characteristics of the Tool and Work Materials

CIRP Annals ◽

10.1016/s0007-8506(07)63359-9 ◽

1983 ◽

Vol 32 (1) ◽

pp. 47-51 ◽

Cited By ~ 3

Author(s):

H.J. Xu ◽

X.C. Tong ◽

X.S. Zhao ◽

Y.Z. Zhang ◽

J. Peklenik

Keyword(s):

Heating Rate ◽

High Heating Rate ◽

High Heating

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Metal oxide nanoparticles formed from solution droplets under high heating rate

Experimental Thermal and Fluid Science ◽

10.1016/j.expthermflusci.2012.03.029 ◽

2012 ◽

Vol 43 ◽

pp. 23-31 ◽

Cited By ~ 1

Author(s):

Francesco Carbone ◽

Alberto C. Barone ◽

Federico Beretta ◽

Andrea D’Anna

Keyword(s):

Metal Oxide ◽

Heating Rate ◽

Metal Oxide Nanoparticles ◽

Oxide Nanoparticles ◽

High Heating Rate ◽

High Heating

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Gasification of High Heating-rate Biomass-derived Chars at Elevated Temperatures

Energy Procedia ◽

10.1016/j.egypro.2017.03.369 ◽

2017 ◽

Vol 105 ◽

pp. 642-647

Author(s):

Tian Li ◽

Yanqing Niu ◽

Liang Wang ◽

Terese Løvås

Keyword(s):

Heating Rate ◽

Elevated Temperatures ◽

High Heating Rate ◽

High Heating

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XPS and Electron Microscopy Study of Oxide-Scale Evolution on Ignition Resistant Mg-3Ca Alloy at Low and High Heating Rates

Experimental Results ◽

10.1017/exp.2020.41 ◽

2020 ◽

Vol 1 ◽

Author(s):

L. A. Villegas-Armenta ◽

R. A. L. Drew ◽

M. O. Pekguleryuz

Keyword(s):

Oxide Scale ◽

Heating Rate ◽

Photoelectron Spectroscopy ◽

Microscopy Study ◽

Electron Microscopy Study ◽

High Heating Rate ◽

Heating Rates ◽

Oxide Interface ◽

Protective Oxide ◽

High Heating

AbstractEarlier work by the authors suggested that the formation of molten eutectic regions in Mg-Ca binary alloys caused a discrepancy in ignition temperature when different heating rates are used. This effect was observed for alloys where Ca content is greater than 1 wt%. In this work, the effect of two heating rates (25 °C/min and 45 °C/min) on the ignition resistance of Mg-3Ca is evaluated in terms of oxide growth using X-ray Photoelectron Spectroscopy. It is found that the molten eutectic regions develop a thin oxide scale of ~100 nm rich in Ca at either heating rate. The results prove that under the high heating rate, solid intermetallics are oxidized forming CaO nodules at the metal/oxide interface that eventually contribute to the formation of a thick and non-protective oxide scale in the liquid state.

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