Thermophysical properties of thoriated tungsten above 3600 K by a pulse-heating method

Thoriated tungsten (tungsten, 98% thorium oxide, 2%) is a widely used electrode material for inert-gas arc-welding. A subsecond pulse-heating technique was applied to rod specimens; radiance temperature was measured by high-speed pyrometry. Literature values of the temperature dependence of the norm...

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Bibliographic Details
Published in:International journal of thermophysics 1996-09, Vol.17 (5), p.1025-1036
Main Authors: RIGHINI, F, SPISIAK, J, BUSSOLINO, G. C, ROSSO, A, WHITE, G. K
Format: Article
Language:English
Subjects:
Applied sciences
Calibration
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Cooling
Electric conductivity
Electric heating
Electric insulators
Electrical and thermal conduction in crystalline metals and alloys
Electronic conduction in metals and alloys
Electronic transport in condensed matter
Exact sciences and technology
Heat capacities of solids
High temperature properties
Inert gas welding
Metal melting
Metals. Metallurgy
Physics
Pyrometry
Thermal effects
Thermal properties of condensed matter
Thermal properties of crystalline solids
Thermodynamic properties
Thoria
Tungsten
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Summary:Thoriated tungsten (tungsten, 98% thorium oxide, 2%) is a widely used electrode material for inert-gas arc-welding. A subsecond pulse-heating technique was applied to rod specimens; radiance temperature was measured by high-speed pyrometry. Literature values of the temperature dependence of the normal spectral emissivity of tungsten were used to obtain true temperatures, with the melting point of thoriated tungsten as a calibration point. Experimental results obtained in the temperature range from 3600 K to the melting point (3693 K) are presented and discussed, along with data obtained during the initial part of the free cooling period. The electrical resistivity results show a regular behavior up to the melting point, indicating that thoria remains an insulator up to 3680 K. During heating, a heat capacity anomaly is found near 3666 K, interpreted as the melting point of thoria. During cooling, two anomalies are found, the first one with a peak near 3660 K and a second one (possibly a Frenkel disorder) with a peak near 3148 K.
ISSN:0195-928X
1572-9567
DOI:10.1007/BF01441991