XAFS Investigation of Platinum Impurities in Phosphate Glasses
The coordination environments of Pt impurities in a ternary K-aluminophosphate (KAP) glass and commercial K,Mg-aluminophosphate (KMAP) laser glasses have been investigated by Pt LIII-edge X-ray absorption fine structure (XAFS) spectroscopy. Pt valence in the KAP glass depends on the melt preparation atmosphere. Pt4+ ions form in melts that are bubbled with oxygen, whereas metallic Pt particles form when these same samples are remelted in air. Residual chlorine in KMAP glasses has an effect on Pt bonding. In chlorine-free samples, Pt4+ ions are coordinated with ∼5.4 (8) oxygen atoms with an average distance of 2.02 (1) Å. For glasses with low chlorine contents (<200 ppm Cl), the Pt4+ ions have both O and Cl atoms in the first coordination shell. As the Cl concentration increases, the number of O nearest neighbors decreases and for Cl:Pt > 5, only Cl nearest neighbors are observed. Pt4+ ions in these latter glasses are coordinated by ∼5.5 (8) Cl atoms at an average distance of 2.27 (2) Å.
M. Karabulut and G. K. Marasinghe and C. A. Click and E. Metwalli and R. K. Brow and D. K. Shuh and T. I. Suratwala and C. H. Booth and J. J. Bucher and J. H. Campbell, "XAFS Investigation of Platinum Impurities in Phosphate Glasses," Journal of American Ceramic Society, John Wiley & Sons, May 2002.
Materials Science and Engineering
Lawrence Livermore National Laboratory
Keywords and Phrases
X-Ray Methods; Glass; Platinum
Article - Conference proceedings
© 2002 John Wiley & Sons, All rights reserved.