The optical emissivity of titanium and zirconium
F. J. Bradshaw
A method of measuring the optical emissivity of titanium and zirconium using eddy current heating is described. The specimen consisted of a cylinder of metal drilled with a small black-body hole, and its real and apparent temperatures were measured with an optical pyrometer at a mean wavelength of 0.652μ. The variation of emissivity with temperature was investigated and the precautions taken to avoid errors are described.
Materials
Curve 1
Wavelength μ: 0.652
Temperature Range, K: 1113
Geometry θ': ~0°
Reported Error, %: 2.2
Composition (weight percent), Specifications and Remarks: 0.19 N, 0.096 Fe, 0.073 O, 0.059 C, 0.056 Si, <0.002 Ni; obtained in powder form, sintered in vacuo, worked into fully dense bars, and turned into cylinder; hexagonal crystal structure; polished by normal metallographic means using magnesia in final stages; measured in vacuum (2 x 10-5 to 8 x 10-6 mm Hg); mean value of three runs.
Curve 2
Wavelength μ: 0.652
Temperature Range, K: 1223-1623
Geometry θ': ~0°
Reported Error, %: 2.2
Composition (weight percent), Specifications and Remarks: Different sample, same as above specimen and conditions except body centered cubic structure.
Curve 1
Wavelength μ: 0.652
Temperature Range, K: 1098
Geometry θ': ~0°
Reported Error, %: 2.8
Composition (weight percent), Specifications and Remarks: 3. 0 Hf, 0. 36 Fe, 0. 17 N, 0.13 Si, 0. 075 0, 0. 048 C, 0. 02 Ni, Zr balance; obtained in powder form, sintered in vacuo, worked into fully dense bars, and turned into cylinder ; hexagonal crystal structure; polished by normal metallographic methods using magnesia in final stages; measured in vacuum (2 x 10-5 to 8 x 10-6 mm Hg); mean value of two runs.
Curve 2
Wavelength μ: 0.652
Temperature Range, K: 1581
Geometry θ': ~0°
Reported Error, %: 2.8
Composition (weight percent), Specifications and Remarks: Above specimen and conditions except body centered cubic structure.