What is it about?
The structure of glassy B2O3 under pressure was investigated by neutron diffraction and molecular dynamics simulations made using a newly developed aspherical ion model. The results reveal three densification regimes involving (i) the persistence of BO3 triangles but the dissolution of boroxyl rings, (ii) the transformation of BO3 triangles to BO4 tetrahedral units as boroxyl rings are eliminated, and (iii) the continued transformation of BO3 to BO4 units in the absence of boroxyl rings to form a tetrahedral glass.
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Photo by Dominik Zumtobel on Unsplash
Why is it important?
B2O3 is an essential component in a wide variety of glasses having practical applications. It's valuable to know how the structure of B2O3 glass varies with pressure as a prelude for modelling the behaviour of these materials under the pressures experienced during sharp-contact loading, .e.g., when glass is indented or scratched. The new results tie together those obtained from other experimental techniques to reveal three densification regimes. The comparison between experiment and simulation shows that the aspherical ion model is able to provide results of unprecedented accuracy at pressures up to at least 10 GPa.
Perspectives
It was rewarding to see how the development of the aspherical ion model for B2O3 benefitted from the provision of the experimental results.
Professor Philip S Salmon
University of Bath
Read the Original
This page is a summary of: Density-driven structural transformations in B 2 O 3 glass , Physical Review B, July 2014, American Physical Society (APS),
DOI: 10.1103/physrevb.90.024206.
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