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Journal of Coatings Technology

, Volume 74, Issue 932, pp 55–63 | Cite as

Optical reflectance of metallic coatings: Effect of aluminum flake orientation

  • Li-Piin Sung
  • Maria E. Nadal
  • Mary E. McKnight
  • Egon Marx
  • Brent Laurenti
Technical Articles

Abstract

A set of aluminum-flake pigmented coatings having different flake orientations was prepared using various spraying conditions. The flake surface topography and the orientations of individual flakes were determined from images obtained by laser scanning confocal microscopy. Reflectance measurements were carried out to quantify the optical properties of the coatings. Both a Gaussian distribution (used to represent the measured flake orientation distribution) and a topographic map (including local surface roughness and orientation) of the flakes were then used as input to a ray scattering model to calculate the optical reflectance of each coatings Flake orientation distributions and examples of measured optical reflectance as a function of scattering angle are shown, and the latter are compared to calculated reflectance values.

Keywords

Laser Scanning Confocal Microscope Optical Reflectance Metallic Coating Flake Surface Pearlescent Paint 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. (1).
    Wicks, Z.W., Jones, F.N. Jr., and Pappas, S.P.,Organic Coatings: Science and Technology, John Wiley & Sons, Inc., 1992.Google Scholar
  2. (2).
    McCamy, C.S., “Observation and Measurement of the Appearance of Metallic Materials, Part I. Macro Appearance & Part II. Micro Appearance,”Color Research and Application, 21, 292–304 (1996), 23, 362–372 (1998).CrossRefGoogle Scholar
  3. (3).
    Rodrigues, A.B.J., “Color and Appearance Measurement of Metallic and Pearlescent Finishes,”ASTM Standardization News, 68–72, October (1995).Google Scholar
  4. (4).
    Tachi, K., Okuda, C., and Suzuki, S., “Mechanism of Aluminum Flake Orientation in Metallic Topcoats,”Journal of Coatings Technology,62, No. 782, 43 (1990).Google Scholar
  5. (5).
    Tachi, K. and Okuda, C., “Color Variation of Automotive Metallic Finishes,”Journal of Coatings Technology,64, No. 811, 71–77 (1992).Google Scholar
  6. (6).
    Wojtkowiak, J.J., “Effect of Film Viscosity on Aluminum Flake Orientation in Thermoplastic Acrylic Coatings,”Journal of Coatings Technology,51, No. 658, 111 (1979).Google Scholar
  7. (7).
    Kettler, W.H. and Richter, G., “Investigation on Topology of Platelet-Like Effect-Pigments in Automotive Surface-Coatings,”Prog. Org. Coat., 31, 297–306 (1997).CrossRefGoogle Scholar
  8. (8).
    Sung, L.-P., Nadal, M.E., McKnight, M.E., Marx, E., Dutruc, R., and Laurenti, B., “Effect of Aluminum Flake Orientation on Coating Appearance,”Proc. 79th Annual Meeting Technical Program of the FSCT, Nov. 5–7, 2001, Atlanta, GA, 453–466 (2001).Google Scholar
  9. (9).
    Corle, T.R., and Kino, G.S.,Confocal Scanning Optical Microscopy and Related Imaging Systems, Academic Press (1996).Google Scholar
  10. (10).
    Barnes, P.Y., Early, E.A., and Parr, A.C.,Spectral Reflectance, NIST Special Publication, 250–48, 1998.Google Scholar
  11. (11).
    McKnight, M.E., Marx, E., Nadal, M.E., Vorburger, T.V., Barnes, P.Y., and Galler, M., “Measurements and Predictions of Light Scattering by Clear Epoxy Coatings,”Applied Optics, 40, 2159–2168 (2001).PubMedCrossRefADSGoogle Scholar
  12. (12).
    Germer, T.A. and Asmail, C.C., “Polarization of Light Scattered by Microrough Surfaces and Subsurface Defects,”J. Opt. Soc. Am. A, 16, 1326–1332 (1999).CrossRefADSGoogle Scholar
  13. (13).
    Barrick, D.E., “Rough Surface Scattering Based on the Specular Point Theory,”IEEE Trans. Antennas Propagat., 16, 449–454 (1968).CrossRefADSGoogle Scholar
  14. (14).
    Born, M. and Wolf, E.,Principles of Optics, 6th Edition, p. 42, Pergamon, 1980.Google Scholar

Copyright information

© Springer Science+Business Media 2002

Authors and Affiliations

  • Li-Piin Sung
    • 1
  • Maria E. Nadal
    • 1
  • Mary E. McKnight
    • 1
  • Egon Marx
    • 1
  • Brent Laurenti
    • 2
  1. 1.National Institute of Standards and TechnologyUSA
  2. 2.Eckart AmericaUSA

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