Effect of Nb&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; addition to SnO–P&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; glass

Fukui, Satoshi; Sakida, Shinichi; Benino, Yasuhiko; Nanba, Tokuro

doi:10.2109/jcersj2.120.530

Cited by 8 publications

(2 citation statements)

References 12 publications

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“…Therefore, the increase in edge-sharing VO x polyhedra might improve the water durability. Regarding the structure of PO 4 polyhedra, several papers reported that phosphate glass that has PO 4 tetrahedra with Q 0 or Q 1 structures shows good water durability, suggesting that the low polarizability in PO 4 tetrahedral units makes it hard to attract polar water molecules [45][46][47] . Therefore, the reason that the water durability improved in the range of glasses VP0 to VP44 is because the structures of the PO 4 tetrahedral units were only Q 0 and Q 1 structures, unlike the Q 3 structures in the VP100 glass.…”

Section: Discussionmentioning

confidence: 99%

Controlling oxygen coordination and valence of network forming cations

Aoyagi

Kohara

Naito

et al. 2020

Sci Rep

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Understanding the structure-property relationship of glass material is still challenging due to a lack of periodicity in disordered materials. Here, we report the properties and atomic structure of vanadium phosphate glasses characterized by reverse Monte Carlo modelling based on neutron/synchrotron X-ray diffraction and EXAFS data, supplemented by Raman and NMR spectroscopy. In vanadium-rich glass, the water durability, thermal stability and hardness improve as the amount of P 2 o 5 increases, and the network former of the glass changes from VO x polyhedra to the interplay between VO x polyhedra and po 4 tetrahedra. We find for the first time that the coordination number of oxygen atoms around a V 4+ is four, which is an unusually small coordination number, and plays an important role for water durability, thermal stability and hardness. Furthermore, we show that the similarity between glass and crystal beyond the nearest neighbour distance is important for glass properties. These results demonstrate that controlling the oxygen coordination and valence of the network-forming cation is necessary for designing the properties of glass. Oxide glass components are basically classified into network formers, network modifiers and intermediates by Zachariasen 1 and Sun 2. Typical network formers satisfy Zachariasen's rules 1 , but V 2 O 5 is classified as a network former 1 or intermediate 3. This is because it is hard for this oxide to form glass on its own because the oxygen coordination number is five in a crystalline phase, which is larger than the coordination number of typical network formers of three and four. V 2 O 5 based glasses have been widely studied for decades because V 2 O 5 glass is a typical semiconducting glass originating from hopping conduction. Indeed, not only fundamental research on electrical properties 4-8 but also applied research on cathode materials for lithium, sodium and magnesium ion batteries have been reported 9-12. This glass also has a low glass transition temperature and relatively low thermal expansion 4. These are quite attractive properties for low-melting glass used for sealing. In this field, lead borate glass with a high percentage of PbO has been applied to sealing below 400 °C in electronic devices, such as IC ceramic packages, crystal oscillators and micro-electro-mechanical systems. Since lead components are a hazardous substance for human health and the environment, it is necessary to avoid the use of PbO, and hence, V 2 O 5 based glass is a promising material for overcoming this problem 13-19. However, there are two critical problems that face the practical application of V 2 O 5 based glass: poor water durability and low thermal stability.

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Section: Discussionmentioning

confidence: 99%

Controlling oxygen coordination and valence of network forming cations

Aoyagi

Kohara

Naito

et al. 2020

Sci Rep

View full text Add to dashboard Cite

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“…This problem restricts its wider application in optical devices [1]. The polynary system shows larger glass-forming region, which can be prepared into bigger glass with high refractive index [18][19][20]. 20La 2 O 3 -(80 À x)TiO 2 -xNb 2 O 5 ternary system glasses have been successfully prepared with diameters larger than 3 mm by aerodynamic levitation.…”

Section: Introductionmentioning

confidence: 99%