Abstract
The effects of the addition of various alloying elements (In, Sn, Zn) of up to 4 mass % on the optical properties of Au-Pt-Pd-based high noble dental alloys were investigated by means of spectrophotometric colourimetry. Spectral reflectance data from the mirror-polished flat samples were collected at 10 nm intervals in the wavelengths ranging from 360 nm to 740 nm under the CIE standard illuminant D65 and the observer of 10 degrees. Three dimensional colour coordinates in the CIEL *a*b* andL *C*h colour spaces were also obtained to specify the alloy colour. The alloying addition of a small amount of Sn and/or In increased the reflectance in the long-wavelength range and decreased the reflectance in the shortwavelength range. As a result, the maximum slope of the spectral reflectance curve at the absorption edge near 520 nm apparently increased with the additions of Sn and/or In. This change in shape of the spectral reflectance curve caused the increased chromaticity indices,a*, b*, and chroma,C*. On the other hand, the hue angle was not greatly affected by the alloying elements, with the exception of the alloy containing 4 mass % Sn showing a slightly lower hue angle. It was evidenced that in the single-phase structured alloys the average number of valence electrons per atom,e/a, in an alloy is a controlling factor of the colour of Au−Pt−Pd-based high noble dental alloys. That is, by increasinge/a-value,a*-, b*-, C*- coordinates systematically increased, giving a slight gold tinge to the parent Au-Pt-Pd alloy within the limitation that the structure of an alloy is a single phase. The addition of Sn of 2 mass % or more produced a small amount of the second phase of possible intermetallic compounds between Sn and Pd or Pt. The coexistence of a small amount of the second phase of possible intermetallic compounds further increased a gold tinge. However, the inclusion of 4 mass % Sn to the parent Au-Pt-Pd alloy gave a very light tint of red to the alloy. Results of the present study are expected to be useful in controlling colour of Au-Pt-Pd-based high noble dental alloys.
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References
R. M. German,Journal of Dental Research, 1980,59, 1960
R. van Noort, ‘Introduction to Dental Materials’, Mosby, London, 1994, pp. 219–221
R. M. German,International Metals Reviews, 1982,27, 260
H. Knosp, R. J. Holliday, C. W. Corti,Gold Bulletin, 2003,36, 93
R. M. German, M. M. Guzowski, D. C. Wright,Journal of Metals, 1980,32, 20
W. D. Callister, Jr., ‘Materials Science and Engineering: An Introduction’, John Wiley & Sons, Inc., New York, 1985, pp. 535–536
K. E. Saeger and J. Rodies,Gold Bulletin, 1977,10, 10
T. Shiraishi, Y. Takuma, E. Miura, Y. Tanaka, K. Hisatsune,Journal of Materials Science: Materials in Medicine, 2003,14, 1021
N. F. Mott and H. Jones, ‘The Theory of the Properties of Metals and Alloys’, Dover Publications, Inc., New York, 1958, pp. 172–173
H. Sato and R. S. Toth,Physical Review, 1961,124, 1833
K. Ohshima and D. Watanabe,Acta Crystallographica, 1973,A29, 520
C. Norris and H. P. Myers,Journal of Physics F: Metal Physics, 1971,1, 62
C. Kittel, ‘Introduction to Solid State Physics’, 2nd edn., John Wiley & Sons, Inc., New York, 1956, p. 320
R. E. Reed-Hill, ‘Physical Metallurgy Principles’, 2nd edn., PWS-KENT Publishing Company, Boston, 1973, pp. 112–115
J. Friedel,Canadian Journal of Physics, 1956,34, 1190
T. Shiraishi, K. Hisatsune, Y. Tanaka, E. Miura, Y. Takuma,Gold Bulletin, 2001,34, 129
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Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License ( https://creativecommons.org/licenses/by-nc/2.0 ), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Shiraishi, T., Geis-Gerstorfer, J. Optical properties of Au−Pt−Pd-based high noble dental alloys. Gold Bull 39, 9–15 (2006). https://doi.org/10.1007/BF03215527
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DOI: https://doi.org/10.1007/BF03215527