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Journal of Materials Science

, Volume 44, Issue 11, pp 2796–2804 | Cite as

Optical properties and microstructures of Pd-free Ag–Au–Pt–Cu dental alloys

  • Takanobu Shiraishi
  • Yasuko Takuma
  • Takeshi Fujita
  • Eri Miura
  • Kunihiro Hisatsune
Article

Abstract

Nine experimental Pd-free Ag–Au–Pt–Cu dental alloys containing 10 at.% Pt and 10–35 at.% Au were prepared and their optical properties and microstructures were investigated by means of spectrophotometric colorimetry, optical microscopy, and electron probe microanalysis. All the alloys were annealed at 850 °C and mirror-polished to observe their reflectance curves in the visible spectrum and three-dimensional color coordinates. All the alloys were composed of a major phase of Ag–Au-rich matrix and a minor and almost colorless Pt–Cu-rich phase. It was found that the color of the alloys was substantially controlled by the Ag–Au-rich matrix and that with increasing Au/Ag atomic ratio from 0.130 to 0.996, the yellow-blue chromaticity index b * increased from 8.0 to 14.4, giving a pale yellow color. This systematic increase in yellowness was caused by a continuous shift of the absorption edge of reflectance curve toward longer wavelengths with increasing Au/Ag atomic ratio.

Keywords

Spectral Reflectance Quaternary Alloy Dental Alloy Chromaticity Index CIELAB Color Space 
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.

Notes

Acknowledgements

This research was supported in part by “The Grant-in-Aid for Scientific Research” from The Ministry of Education, Culture, Sports, Science and Technology in Japan (13672044). The authors also thank Mr. Y. Murakami of The Institute of Metals Research, Tohoku University (Sendai, Japan) for his assistance in electron probe microanalysis.

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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Takanobu Shiraishi
    • 1
  • Yasuko Takuma
    • 1
  • Takeshi Fujita
    • 1
  • Eri Miura
    • 1
  • Kunihiro Hisatsune
    • 1
  1. 1.Department of Dental and Biomedical Materials Science, Unit of Basic Medical Sciences, Graduate School of Biomedical SciencesNagasaki UniversityNagasakiJapan

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