Liquid State Spectral Emissivities of Titanium, Vanadium, Zirconium, Molybdenum, and Platinum in an Electron Beam Furnace.
The normal spectral emissivities of liquid ti, V, zr, mo, and pt were determined at the fusion temperatures and were estimated above the melting points by using adjusted two-color temperatures as approximations of the true temperatures for substitution in wien's equation. Simultaneous brightness temperatures were determined with a micro-optical pyrometer. The true temperature ranges covered were 1,668 deg to 1,885 deg c for ti; 1,919 deg to 2,013 deg c for v; 1,855 deg to 2,367 deg c for zr; 2,610 deg to 2,751 deg c for mo, and 1,772 deg to 1,990 deg c for pt. The spectral emissivities for titanium and zirconium decreased with increasing temperature. At an effective wavelength (^) of 658 mu the emissivity of titanium ranged from 0.51 to 0.45 and zirconium, from 0.47 to 0.41. The emissivities of vanadium (^ = 658 mu) and molybdenum (^ = 657 mu) were constant at 0.41 +/- 0.02 and 0.33 +/- 0.01, Respectively. The spectral emissivity of platinum (^ = 658 mu) was constant at 0.39 +/- 0.02 Up to 1,900 deg c; above that temperature anomalous data were obtained. A mass spectrometric study indicated that platinum was reacting with backstreaming silicon vapors from the diffusion pump when the ambient pressure was greater than 2 x 10-5 torr.