This work focuses on a particular behavior of dense yttria samples fabricated by spark plasma sintering, which display a reddish coloration when subjected to X-ray irradiation. The reddish coloration appears exclusively in sintered material. Optical measurements, X-ray photoelectron spectroscopy and chemical methods have been used to investigate the properties of consolidated yttria. The results obtained suggest that the sintered material exhibits a relatively high concentration of oxygen vacancies. Thermoluminescence measurements indicate that they act as electronic trapping sites. A generalized-order kinetic analysis suggests that at least five different shallow traps can be identified. (C) 2014 Elsevier B.V. All rights reserved.
X-ray induced color change on dense yttria samples obtained by spark plasma sintering / Attia Mohammed A., A; Garroni, Sebastiano; Chiriu, D; Ricci, C; Delogu, F; Orru, R; Cao, G.. - In: CHEMICAL PHYSICS LETTERS. - ISSN 0009-2614. - 618:(2015), pp. 108-113. [10.1016/j.cplett.2014.11.009]