Radiance temperature of niobium at its melting point

Cezairliyan, A.

doi:10.6028/jres.077a.020

Cited by 18 publications

(4 citation statements)

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“…It has been observed [26] that when a pure metal strip is melted its surface radiance temperature remains constant, at least during the initial melting period, and that this value is reproducible for different specimens of the same metal irrespective of the initial surface conditions. During the last two decades, a significant amount of research has been performed, both at the NIST and the IMGC, on measurements of the radiance temperatures of pure metals at their melting points.…”

Section: Surface Radiance Temperature At the Melting Pointmentioning

confidence: 99%

See 1 more Smart Citation

Electron Density Control Using Fast Gas Puffing in Reversed-field Pinch Device, TPE-RX

Sakakita¹,

Yagi²,

Koguchi³

et al. 2004

Jpn. J. Appl. Phys.

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A brief summary is given of the developments in optical techniques for rapid temperature measurement during the last three decades in two national laboratories, the National Institute of Standards and Technology in the USA and the Istituto di Metrologia "G. Colonnetti" in Italy. Results of research conducted in originating and advancing the state-of-the-art in high-speed (millisecond-and microsecond-resolution) pyrometry for measurement of temperatures in the range 1000 K to 5000 K are discussed. The main emphasis is on several key issues related to high-speed pyrometry including: high-speed operation, calibration of pyrometers, determination of true temperature and high-temperature reference points. Anticipated future directions in research, developments and applications in high-speed pyrometry are briefly discussed.

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Section: Surface Radiance Temperature At the Melting Pointmentioning

confidence: 99%

“…Variation of normal spectral emissivity at the melting point as a function of wavelength for niobium. Data obtained at the NIST ( [26], [28], [7]) and at the IMGC (ⅷ and ⅜ [29]). The curve represents the quadratic function, fitted by the least-squares method, to the data from the two laboratories.…”

Section: Future Directionsmentioning

confidence: 99%

Electron Density Control Using Fast Gas Puffing in Reversed-field Pinch Device, TPE-RX

Sakakita¹,

Yagi²,

Koguchi³

et al. 2004

Jpn. J. Appl. Phys.

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“…A subsecond-duration pulse heating technique was used earlier to measure the melting point and the radiance temperature 1 at the melting point of several refractory metals [ 1 – 7 ]. 2 In the present study, the same technique is used for similar measurements on hafnium containing 3.12 weight percent zirconium.…”

Section: Introductionmentioning

confidence: 99%

Measurement of melting point and radiance temperature (at melting point and at 653 nm) of hafnium-3 (wt %) zirconium by a pulse heating method

Cezairliyan¹,

McClure²

1976

J. RES. NATL. BUR. STAN. SECT. A.

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A subsecond duration pulse heating mcthod is used to measure the melting point and radiance temperature (at G.'i3 nm) at the melting point of hafnium containing 3.12 weight percent zirconium. The results yield a value of 2471 K for the melting point on the International Practical Temperature Scale of 1968. The radiance temperature (at G!)3 nm) of this material at its melting point iH 2236 K, and the corresponding normal spectral em ittance is 0.39. Estimated inaccuraci es arc: 10 K in the melting point and in the radiance temperature, and 5 percent in the normal spectral emittance.Key "'ords: Hafnium; high-~peed measurement; high temperature; melting puint; pyrometry; radiance temperature. . IntroductionA subsecond-duration pulse heating technique was used earlier to measure the melting point and the radiance temperature 1 at the melLing point of several refractory metals [1 -7] .2 In the present study, the same technique is used foJ' similar meaSUlements on hafnium containing 3.12 weight percent zirconium.The method is based on rapid resistive self-heating of the specimen from loom temperature to high temperatures (above 1500 K) in less than one second by the passage of an electrical current pulse through it; and on measuring, with millisecond resolution, such experimental quantities as current through the specimen, potential drop across the specimen, and the specimen temperature. Temperature is measured with a high-speed photoelectric pyrometer [8], which permits 1200 evaluations of specimen temperature per second. Details regarding the construction and operation of the measurement system, the methods of measuring experimental quantities, and other pertinent information, such as the formulation of relations for properties, elTor analysis, etc. are given in earlier publications [9,10]. MeasurementsThe material used in this study was a hafnium 'This work was supported in part by tho U.S. Air Force Office of Scientific Research.I Radiance temperature (sometimes referred to as brightness temperature) is the apparent temperature of the specimen surface correspo nding to the effeclive wavelength of the measuring pyrometer.2 Figures in brackets indicate tho literature references at the ('11(1 of this paprl'. alloy containing 3.12 (wt. %) zirconium 3 (referred to in this paper as hafnium-3 (wt. %) zirconium. The alloy specimens were 99.97 percent pure and contained, according to the manufacturer's analysis, the following impurities in ppm by weight: C, 15; 0,10; N, 10; Al, 20; Ca, 10; Cu, 10; Fe, < 50; Mn, 20; Mo, 10; Nb, 30; Si, 20; Ta, 30; Ti, 10; W, 10. The total amount of all other detected clements was less than 70 ppm, each element being below 10 ppm limit. Measuremen ts were performed on two specimens in the form of tubes and nine specimens in the form of strips. The tubes, used to determine the ~elting point, were fabricated from rods by removmg the center portion using an electro-erosion technique. A small rectangular hole (1 x 0.5 mm) was fabricated in the wall at the middle of the specimen to approximate b...

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“…A more practical approach than a black-body configuration is for the pyrometer to be aimed at the surface of a melting metal. It has been observed [26] that when a pure metal strip is melted its surface radiance temperature remains constant, at least during the initial melting period, and that this value is reproducible for different specimens of the same metal irrespective of the initial surface conditions.…”

Section: Surface Radiance Temperature At the Melting Pointmentioning

confidence: 99%