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The charge state of titanium ions in Pd‐doped Ti: CMAS glass and glass‐ceramics
Author(s) -
Golovchak Roman,
Davis Mark J.,
Vullo Paula,
Astashkin Andrei,
Nichols Laura,
Ingram Adam,
Jain Himanshu
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14791
Subject(s) - materials science , x ray photoelectron spectroscopy , glass ceramic , phosphate glass , analytical chemistry (journal) , titanium , ceramic , spectroscopy , rutile , ion , doping , mineralogy , chemical engineering , composite material , metallurgy , chemistry , organic chemistry , physics , optoelectronics , chromatography , quantum mechanics , engineering
We have investigated the role of charge state of Ti in the electronic properties and structure of electrically conductive CMAS ‐TiO 2 ‐Pd glass and glass‐ceramics by X‐ray photoelectron spectroscopy, electron paramagnetic resonance, positron annihilation lifetime spectroscopy, and fluorescence spectroscopy. These studies suggest the concentration of Ti 3+ ions was, at most, ~0.1 wt% in glass‐ceramics devitrified in the reducing atmosphere of forming gas; no other glass or glass‐ceramic samples exhibited measurable levels of Ti 3+ . The observed fluorescence at liquid nitrogen temperature in parent glasses and glass‐ceramics obtained in air is explained by UV ‐induced charge‐transfer processes involving Ti 4+ ions and oxygen surroundings. The X‐ray photoelectron spectroscopy data are correlated with rutile, anorthite, diopside, and titanite crystalline phases identified in Pd‐free and Pd‐doped Ti: CMAS glass‐ceramics earlier.