Mapping the structural trends in zinc aluminosilicate glasses

What is it about?

The structural role of zinc in aluminosilicate glasses was investigated over a wide composition range by combining neutron and high-energy x-ray diffraction with 27Al magic angle spinning NMR spectroscopy. The results were interpreted using an analytical model for the composition-dependent structure in which the zinc ions do not act as network formers.

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Photo by JJ Ying on Unsplash

Photo by JJ Ying on Unsplash

Why is it important?

Zinc is an essential additive in many commercial glasses where it is used to improve the chemical resistance and mechanical properties of the material. It is also an important ingredient in bioactive glasses, playing a vital role in bone formation, resorption, and tissue engineering. The structural role that zinc plays is, however, mysterious because of (i) its ability to adopt different coordination environments and (ii) the difficulty in reliably interpreting the data from spectroscopic techniques such as 67Zn solid-state and EXAFS. We find that the coordination environment of zinc is not invariant with the glass composition and depends on whether zinc plays a predominantly network-modifying or charge-compensating role. Our work reveals and quantifies the structural role of a key element that is often classified as an “intermediate” in glass science, sitting in the ambiguous space between traditional network-forming elements such as silicon and network-modifying/charge-compensating elements such as calcium.

Perspectives