Microsc. Microanal. Microstruct. 2, 97-106 (1991)
DOI: 10.1051/mmm:019910020109700

Scanning electron microscopy and X-ray energy dispersive spectroscopy studies of defects in lead glasses

Giovanni Valdrè

Department of Mineralogical Sciences, Piazza di Porta S. Donato 1, I-40126 Bologna, Italy Centre of Electron Microscopy c/o Dept. of Physics, University of Bologna, I-40126 Bologna, Italy

Abstract
Scanning electron microscopy (SEM) observations, quantitative X-ray energy dispersive spectroscopy (EDS) and windowless EDS (WEDS) of typical defects in lead glasses are presented. The micrographs, obtained mainly by means of a high efficiency backscattered electron (BSE) detector, showed the presence of cords of varying shape, diameter (10-200 μm) and composition, spherical inclusions and cracks; a high density of low Z deposits were found along and in the proximity of the edges of the cracks. Quantitative microanalyses performed on the cords showed the presence of about 3 wt% of Al2O3 and 2 wt% of ZrO2 originating at the interface between the glass and the refractory materials used to hold the melt, and a Pb content lower than the matrix. A high Pb content was instead found in the spherical inclusions, whereas WEDS showed the presence of C in the deposits. These morphological and microchemical results provide to clarify the mechanisms of defect formation.

PACS
6837H - Scanning electron microscopy (SEM) (including EBIC).
6143F - Glasses.

Key words
Scanning electron microscopy -- Defects -- Lead -- Microanalysis -- Electron backscattering -- X-ray energy dispersive spectroscopy


© EDP Sciences 1991