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Study by Extended X‐ray Absorption Fine Structure Technique and Microscopy of the Amorphous State of Titanium Diboride Thin Films
Author(s) -
KALOYEROS ALAIN E.,
WILLIAMS WENDELL S.,
RIZK RICHARD B.,
BROWN FREDERICK C.,
GREENE ALEX E.
Publication year - 1988
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/j.1151-2916.1988.tb07564.x
Subject(s) - amorphous solid , materials science , extended x ray absorption fine structure , crystallization , transmission electron microscopy , titanium , thin film , absorption spectroscopy , analytical chemistry (journal) , absorption (acoustics) , crystallography , chemical engineering , nanotechnology , optics , composite material , metallurgy , chemistry , physics , chromatography , engineering
The local atomic structure and the stability of amorphous titanium diboride (TiB 2 ) thin films, prepared by electron beam vaporization (EBV) of the crystalline compound onto liquid‐nitrogen‐cooled substrates, are studied using extended X‐ray absorption fine structure (EXAFS) and extended energy‐loss fine structure (EXELFS). From a comparison of the extended fine structure spectra of the amorphous films with corresponding spectra of crystalline TiB 2 , accurate information is derived on the nature of local structure, or short‐range order, and on the type and degree of nanostructural atomic disorder σ 2 in amorphous TiB 2 . Subsequent controlled heating experiments and observation and imaging by transmission electron microscopy to determine the crystallization temperature of the amorphous phase show that the crystallization temperature and, thus, the stability of the amorphous phase are strongly dependent on σ 2 . It is shown that minimizing σ 2 is crucial in enhancing the amorphicity. Finally, EXAFS and EXELFS are employed to examine in detail the structural changes induced in amorphous TiB 2 by variations in the EBV deposition parameters.