Radiance Temperatures (in the Wavelength Range 527 to 1500 nm) of Palladium and Platinum at Their Melting Points by a Pulse-Heating Technique

Abstract

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. $\begin{gathered} Palladium Platinum \hfill \\ \overline {1723 K at 529nm} \overline {1904 K at 527 nm} \hfill \\ 1696 K at 626 nm 1871 K at 624 nm \hfill \\ 1687 K at 657 nm 1859 K at 657 nm \hfill \\ 1669 K at 720 nm 1838 K at 717 nm \hfill \\ 1643 K at 811 nm 1806 K at 810 nm \hfill \\ 1614 K at 908 nm 1773 K at 907 nm \hfill \\ 1444 K at 1500 nm 1577 K at 1500 nm \hfill \\ \end{gathered}$ Based on uncertainties arising from pyrometry and specimen conditions, the expanded uncertainty (two-standard deviation level) is about ±7 K for the reported values in the range 527 to 900 nm and about ±8 K for the reported values at 1500 nm.