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Nature of Pd and Ti Metals in the Structure of CMAS Glass and Ceramics
Author(s) -
Golovchak Roman,
Davis Mark J.,
Vullo Paula,
Saiyasombat Chatree,
Jain Himanshu
Publication year - 2014
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.12866
Subject(s) - xanes , x ray photoelectron spectroscopy , extended x ray absorption fine structure , materials science , ceramic , analytical chemistry (journal) , absorption (acoustics) , transmission electron microscopy , spectroscopy , absorption spectroscopy , scanning transmission electron microscopy , scanning electron microscope , chemical engineering , chemistry , nanotechnology , composite material , optics , physics , chromatography , quantum mechanics , engineering
The structure of electrically conductive CMAS ‐TiO 2 ‐Pd glass and ceramics was investigated by transmission electron microscopy ( TEM ), scanning transmission electron microscopy ( STEM ), X‐ray photoelectron spectroscopy ( XPS ), X‐ray absorption near‐edge spectroscopy ( XANES ), and extended X‐ray absorption fine structure spectroscopy ( EXAFS ). The XANES spectra of Ti do not show any significant difference between the glasses ceramized in air or in a reducing “forming” gas, as well as between Pd‐containing versus Pd‐free samples, nor between surface versus bulk of the glass‐ceramic samples. However, EXAFS and XANES data recorded at the Pd K‐edge show significant dependences on whether the glass‐ceramic was ceramized in air or in “forming” gas. The XPS spectra of Ti 2 p core‐level electrons for glasses ceramized in air or “forming” gas also show a strong difference depending on whether the samples did or did not contain Pd. STEM mapping confirms the existence of grains in the form of main crystalline phases identified with XRD , and also reveals the existence of Pd nanoparticles in glasses ceramized in both air and in “forming” gas.