Radiance temperatures (in the wavelength range 530 to 1500 nm) of nickel at its melting point by a false-heating technique

The radiance temperatures (at seven wavelengths in the range 530 to 1500 nm ) of nickel 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 melting point in less than is and on simultaneously measuring specimen radiance temperatures every 0.5 ms. Melting of the spec imen was manifested by a plateau in the radiance temperature-versus-time Fu nction For each wavelength. The melting-point radiance temperatures for a g iven specimen were determined by averaging the measured temperatures along the plateau at each wavelength. The melting-point radiance temperatures for nickel, as determined by averaging the results at each wavelength for 25 s pecimens, are: 1641 K at 530 nm, 1615 K at 627 nm, 1606 K at 657 nm, 1589 K at 722 nm, 1564 K at 812 nm, 1538 K at 908 nm, and 1381 K at 1500 nm. Base d on uncertainties arising from pyrometry and specimen conditions, the comb ined uncertainty (two standard-deviation level) is about +/-6 K for the rep orted values in the range 530 to 900 nm and is about +/-8 K for the reporte d value at 1500 nm.