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Title: Reflectance determination of optical spectral emissivity of metal surfaces at ambient conditions

Optical pyrometry requires knowledge of both spectral radiance and spectral emissivity to accurately measure temperature. No reliable compendium of spectral emissivity data currently exists for common metals in the optical and near-infrared spectral regions where pyrometry is typically performed. In this paper, we measure the spectral reflectivity of numerous common metals, with known surface finishes, between 400 and 1100 nm. The measurements are carried out under ambient conditions, near 300 K at an atmospheric pressure of ~0.78 bar. We then calculate the emissivity as a function of the wavelength for each sample. We define and use the illumination and collection geometries most practical for applying these measurements to radiometric thermometry. We also examine the effect of surface finish upon the relative spectral emissivity of a given material and find qualitative guidelines for predicting the increase in emissivity with increasing surface roughness. Finally, these measurements can both improve the accuracy and precision of optical pyrometry and provide the necessary reference value for converting emerging diagnostic measurements of relative spectral emissivity under extreme dynamic conditions into absolute dynamic spectral emissivity.
Authors:
 [1] ;  [2] ; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Mission Support and Test Services LLC, Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-18-24693
Journal ID: ISSN 0021-8979
Grant/Contract Number:
AC52-06NA25396; NA0003624
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 124; Journal Issue: 10; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mission Support and Test Services LLC, Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1475344
Alternate Identifier(s):
OSTI ID: 1470780

Hartsfield, T. M., Iverson, A. J., and Baldwin, J. K.. Reflectance determination of optical spectral emissivity of metal surfaces at ambient conditions. United States: N. p., Web. doi:10.1063/1.5042601.
Hartsfield, T. M., Iverson, A. J., & Baldwin, J. K.. Reflectance determination of optical spectral emissivity of metal surfaces at ambient conditions. United States. doi:10.1063/1.5042601.
Hartsfield, T. M., Iverson, A. J., and Baldwin, J. K.. 2018. "Reflectance determination of optical spectral emissivity of metal surfaces at ambient conditions". United States. doi:10.1063/1.5042601.
@article{osti_1475344,
title = {Reflectance determination of optical spectral emissivity of metal surfaces at ambient conditions},
author = {Hartsfield, T. M. and Iverson, A. J. and Baldwin, J. K.},
abstractNote = {Optical pyrometry requires knowledge of both spectral radiance and spectral emissivity to accurately measure temperature. No reliable compendium of spectral emissivity data currently exists for common metals in the optical and near-infrared spectral regions where pyrometry is typically performed. In this paper, we measure the spectral reflectivity of numerous common metals, with known surface finishes, between 400 and 1100 nm. The measurements are carried out under ambient conditions, near 300 K at an atmospheric pressure of ~0.78 bar. We then calculate the emissivity as a function of the wavelength for each sample. We define and use the illumination and collection geometries most practical for applying these measurements to radiometric thermometry. We also examine the effect of surface finish upon the relative spectral emissivity of a given material and find qualitative guidelines for predicting the increase in emissivity with increasing surface roughness. Finally, these measurements can both improve the accuracy and precision of optical pyrometry and provide the necessary reference value for converting emerging diagnostic measurements of relative spectral emissivity under extreme dynamic conditions into absolute dynamic spectral emissivity.},
doi = {10.1063/1.5042601},
journal = {Journal of Applied Physics},
number = 10,
volume = 124,
place = {United States},
year = {2018},
month = {9}
}

Works referenced in this record:

Optical Constants of the Noble Metals
journal, December 1972