RADIANCE TEMPERATURES (IN THE WAVELENGTH RANGE 523-907-NM) OF GROUP-IVB TRANSITION-METALS TITANIUM, ZIRCONIUM, AND HAFNIUM AT THEIR MELTING-POINTS BY A PULSE-HEATING TECHNIQUE

The melting-point radiance temperatures (at six wavelengths in the range 523-907 nm) of the Group IVB transition metals titanium, zirconium, and hafnium 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 the specimen radiance temperatures every 0.5 ms with a high-speed six-wavelength pyrometer. 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 were determined by averaging results for several specimens at each wavelength as follows: [GRAPHICS] Based oh estimates of the random and systematic errors arising from pyrometry and specimen conditions, the combined uncertainty (95% confidence level) in the reported values is about +/-8 K at each wavelength.