ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The Mössbauer spectrum of tellurite glasses, containing 5 mol% Fe2O3 as a probe, consists of a paramagnetic quadrupole doublet with an isomer shift of 0.39 ± 0.01 mmsec−1. This indicates that Fe3+ ions are present at substitutional sites of Te4+ ions constituting distorted TeO4 trigonal bipyramids, each of which has one oxygen vacancy at an equatorial site. On increasing the K2O content from O to 35 mol%, the quadrupole splitting (Λ) for potassium tellurite glasses decreases continuously from 0.76 to 0.44 mm sec−1. On the other hand, Λ for magnesium and barium tellurite glasses increases with increasing MgO and BaO content, respectively. When the alkali or alkaline earth oxide contents are the same as each other, Λ increases in proportion to the ionic potential (Z/r) of the alkali or alkaline earth metal ion. These results suggest that the glass matrices of alkaliv and alkaline earth tellurite glasses are continuously changed into a chain and a three-dimensional network structure, respectively. Differential thermal analysis studies reveal that there exists a linear relationship between the glass transition temperatureT g and the quadrupole splitting, indicating thatT g is primarily determined by the magnitude of the distortion of TeO4 trigonal bipyramids. This relationship is also applicable to several oxide glasses.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00575386
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