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Defects in glasses examined by backscattered electron imaging and by x‐ray wavelength and energy dispersive spectroscopy
Author(s) -
Valdrè G.
Publication year - 1992
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.1300210302
Subject(s) - spectroscopy , wavelength , optics , materials science , electron , x ray , energy dispersive x ray spectroscopy , imaging spectroscopy , physics , scanning electron microscope , nuclear physics , astronomy
Typical optical defects in glasses with a high lead content were examined by backscattered electron imaging (BSI), quantitative energy‐dispersive x‐ray spectroscopy (EDS) and windowless EDS (WEDS) in a scanning electron microscope (SEM) and by quantitative wavelength‐dispersive spectroscopy (WDS) in an electron probe micro‐analyser (EPMA). Most of the images were obtained by using a backscattered electron (BSE) detector of high efficiency and excellent atomic number ( Z ) resolution (Δ Z = 0.3). The observations showed the presence of cords of varying shape, diameter (10–200 μm) and composition, spherical inclusions and fractures; the fractures were found to be associated with regions of materials of low Z which have developed gas under electron beam irradiation. Quantitative WDS and EDS microanalyses performed on the cords showed the presence of about 3 wt.% of Al 2 O 3 and 2 wt.% of ZrO 2 , originating from the interaction, at the interface, of the glass and the refractory material used to hold the melted glass, and a lead content lower than the matrix. A high lead content was found, however, in the spherical inclusions. WDS and WEDS showed the presence of carbonates in the low‐ Z regions, which probably developed CO 2 under electron beam irradiation. These morphological and microchemical results are of great importance in clarifying the origin, and hence finding the means of avoidance, of defect formation.