Thermal Expansion of Periclase (MgO) and Tungsten (W) to Melting Temperatures

Densities of liquid oxide melts with melting temperatures above 2000 °C are required to establish mixing models in the liquid state for thermodynamic modeling and advanced additive manufacturing and laser welding of ceramics. Accurate measurements of molten rare earth oxide density were recently reported from experiments with an electrostatic levitator on board the International Space Station. In this work, we present an approach to terrestrial measurements of density and thermal expansion of liquid oxides from high-speed videography using an aero-acoustic levitator with laser heating and machine vision algorithms. The following density values for liquid oxides at melting temperature were obtained: Y2O3 4.6 ± 0.15; Yb2O3 8.4 ± 0.2; Zr0.9Y0.1O1.95 4.7 ± 0.2; Zr0.95Y0.05O1.975 4.9 ± 0.2; HfO2 8.2 ± 0.3 g/cm3. The accuracy of density and thermal expansion measurements can be improved by employing backlight illumination, spectropyrometry and a multi-emitter acoustic levitator.

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Phase Transition and Thermal Expansion of Ba3RB3O9 (R = Sm–Yb, and Y)

High Temperature Materials and Processes ◽

10.1515/htmp-2015-0290 ◽

2017 ◽

Vol 36 (8) ◽

pp. 763-769 ◽

Cited By ~ 1

Author(s):

Rayko Simura ◽

Shohei Kawai ◽

Kazumasa Sugiyama

Keyword(s):

Phase Transition ◽

Thermal Expansion ◽

High Temperature ◽

Thermal Expansion Coefficient ◽

Room Temperature ◽

The Other ◽

X Ray Diffraction ◽

X Ray ◽

Melting Temperatures ◽

Type Phase

AbstractHigh temperature powder X-ray diffraction measurements of Ba3RB3O9 (R=Sm–Yb, and Y) were carried out at temperatures ranging from room temperature to just below the corresponding melting temperatures (1,200–1,300 °C). No phase transition was found for the H-type phase (R$\overline 3 $) with R=Sm–Tb and the L-type phase (P63 cm) with R=Tm–Yb. On the other hand, phase transition from the L phase to the H phase was observed for R=Dy–Er, and Y at around 1,100–1,200 °C. The obtained axial thermal expansion coefficient (ATEC) of the a-axis was larger than that of the c-axis for the H phase, and the ATEC of the c-axis was larger than that of the a-axis for the L phase. The observed anisotropic nature of ATEC is attributed to the distribution of the BO3 anionic group with rigid boron–oxygen bonding in the structures of the H and L phases.

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Thermal expansion of molybdenum-copper and tungsten-copper pseudo-alloys

Soviet Powder Metallurgy and Metal Ceramics ◽

10.1007/bf00774156 ◽

1968 ◽

Vol 7 (3) ◽

pp. 210-215 ◽

Cited By ~ 2

Author(s):

V. B. Rabkin ◽

R. F. Kozlova

Keyword(s):

Thermal Expansion ◽

And Tungsten

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Investigation of thermal expansion of Re--C and Mo--C eutectic systems near its melting temperatures

Vestnik Ob"edinennogo instituta vysokikh temperatur ◽

10.33849/2019204 ◽

2019 ◽

Vol 3 (2) ◽

pp. 22-25

Author(s):

V.N. Senchenko ◽

R.S. Belikov

Keyword(s):

Thermal Expansion ◽

Melting Temperatures ◽

Eutectic Systems

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Microstructural and Microchemical Characterization of Nickel Sulfide Inclusions in Plate Glass

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089123 ◽

1991 ◽

Vol 49 ◽

pp. 962-963

Author(s):

J. Cooper ◽

O. Popoola ◽

W. M. Kriven

Keyword(s):

Thermal Expansion ◽

Phase Transformation ◽

Glass Matrix ◽

Nickel Sulfide ◽

Plate Glass ◽

Thermal Expansion Mismatch ◽

Volume Increase ◽

Β Phase ◽

Microchemical Characterization

Nickel sulfide inclusions have been implicated in the spontaneous fracture of large windows of tempered plate glass. Two alternative explanations for the fracture-initiating behaviour of these inclusions have been proposed: (1) the volume increase which accompanies the α to β phase transformation in stoichiometric NiS, and (2) the thermal expansion mismatch between the nickel sulfide phases and the glass matrix. The microstructure and microchemistry of the small inclusions (80 to 250 μm spheres), needed to determine the cause of fracture, have not been well characterized hitherto. The aim of this communication is to report a detailed TEM and EDS study of the inclusions.

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