Radiance temperatures (in the wavelength range 525 to 906 nm) of vanadium at its melting point by a pulse-heating technique

Tile radiance temperatures (at six wavelengths in tile range 525 to 906 nm) of vanadium at its melting point were measured by a pulse-heating technique. The method is based on rapid resistive self-heating of the specimen from room temperature to its mehing point in less than I s and on simtdtaneously measuring the specimen radiance temperatures every (1.5 ms with a high-speed sixwavelength pyrometer. Melting was manifested by a plateau in the radiance temperature-vs-time functiotl Ibr each wavelength. The melting-point radiance temperatures Ior a given specimen were determined by averaging the measured temperatures along the plateau at each wavelength. Tile melting-point radiance temperatures Ibr ~anadium as determined by averaging the results at each wavelength for 16 specimens (standard deviation in the range 0.3 to 0.4 K, depending on the wavelength) are 2030 K at 525 nm, 1998 K at 622 nm, 1988 K at 652 rim, 1968 K at 714 nm, 1935 K at 809 rim, and 1900 K at 906 nm. Based on estimates of the random and systematic errors that arise fronl pyrometry rind specimen conditions, the resultant uncertainty (2 SD level) in the reported valttes is about + 7 K at each wavelength.