<[email protected]>
Oliver Alderman currently works as Research Scientist at Materials Development Inc., Il, USA and is a Visiting Scientist at Argonne National Laboratory. He obtained an MPhys degree in Physics in 2009, and a PhD in 2013, both at the University of Warwick. His PhD studies included the use of x-ray and neutron diffraction and nuclear magnetic resonance spectroscopy to study the structure of oxide glasses and related materials. Current topics of research include the study of highly refractory melts and the temperature dependent structure of liquids during glass formation or redox, primarily through the use of the aerodynamic levitation and laser heating approach, combined with x-ray and neutron scattering and computational modelling.

Oliver Alderman

Oliver Alderman1,2,* Chris Benmore2, Anthony Tamalonis1, Emma Clark1,, Richard Weber1,2
1Materials Development, Inc., Arlington Heights, IL 60004, USA
2 X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA

Accurate, precise, and often unique, information on the structure of borate liquids, glasses and ceramics can nowadays be obtained using high-quality x-ray diffraction measurements. These have been made possible through several improvements in synchrotron x-ray source brilliance, especially in the high-energy (∼100 keV) regime, image plate detector technologies and sample environments such as the laser-heated aerodynamic levitation furnace.
In this talk I will briefly summarize our published results on B2O3 and sodium borate melts, followed by comparison to new measurements on liquids bearing other modifiers such as calcium, barium and lithium. The unique opportunities presented by the singular structural chemistry of borates will be discussed, followed by the merits of the methodology, the challenges, and suggestions for future directions.

FIGURE 1: Temperature driven reaction involving a change in B–O coordination number and introduction of a nonbridging oxygen (magenta). Bridging oxygen ions are red.

FIGURE 2: Measured average B–O bond lengths as a function of temperature for sodium borate melts and glasses. Open symbols: 8s, filled squares: 60 seconds, filled circles: 60 seconds or 120 seconds (B2O3) measurements. The trend line is a linear fit
FIGURE 3: B–O coordination numbers derived from the bond lengths in Fig. 2 using the bond-valence formula inset.


Reference:
Alderman, O.L.G., et al., Borate melt structure: Temperature dependent B-O bond lengths and coordination numbers from high-energy x-ray diffraction, J. Am. Ceram. Soc., 2018. 101: 3357