Radiance temperatures (in the wavelength range 527 to 1500 nm) of palladium and platinum at their melting points by a pulse-heating technique

The radiance temperatures (at seven wavelengths in the range 527 to 1500 nm) of palladium and platinum at their respective melting points were measured by a pulse-heating technique. The method, based on rapid resistive self-heating of a specimen from room temperature to its melting point in less than 1 s, used two high-speed pyrometers to measure specimen radiance temperatures every 0.5 ms during the heating and melting period. Melting was manifested by a plateau in the radiance temperature-versus-time function for each wavelength. The melting-point radiance temperatures for a given specimen were determined by averaging the measured temperatures along the plateau at each wavelength. The melting-point radiance temperatures for each metal as determined by averaging the results for several specimens at each wavelength are as follows. Palladium: 1723 K at 529 nm, 1696 K at 626 nm, 1687 K at 657 nm, 1669 K at 720 nm, 1643 K at 811 nm, 1614 K at 908 nm and 1444 K at 1500 nm; Platinum: 1904 K at 527 nm, 1871 K at 624 nm, 1859 K at 657 nm, 1838 K at 717 nm, 1806 K at 810 nm, 1773 K at 907 nm and 1577 K at 1500 nm. Based on uncertainties arising from pyrometry and specimen conditions, the expanded uncertainty (two-standard deviation level) is about plus or minus 7 K for the reported values in the range 527 to 900 nm and about plus or minus 8 K for the reported values at 1500 nm.