Wide thermal expansion in Ag0/Au0 nanoparticle doped SiO2-MgO-Al2O3-B2O3-K2O-MgF2 glass-ceramics

This report demonstrates high temperature sealing tendency of alumino-silicate glasses (ASG) on the system SiO2-MgO-Al2O3-B2O3-K2O-MgF2 doped with silver (Ag) and gold (Au) nanoparticles. Density of the melt-quenched (1550 degrees C) glasses were in 2.51-2.55 g.cm(-3). The glasses were heat-treated at 900 +/- 10 degrees C over which the opaque glass-ceramics were obtained with major crystalline phase (XRD) fluorophlogopite mica [KMg3(AlSi3O10)F-2] with secondary phase norbergite (Mg2SiO4 center dot MgF2). FESEM study indicated the development of Rod-like and rock-like crystallite particles (size similar to 1-4 mm) randomly dispersed in mother glass-ceramic which was restructured into nanocrystalline morphology (crystallite size similar to 100- 400 nm) with the aid of Ag-or Au-nanoparticles. The significant change in microstructure influenced the corresponding density (2.51-2.55 g.cm(-3)) and thermal expansion characteristics. Coefficient of thermal expansion (CTE) for ASG was estimated to be 9.96 +/- 0.10 x 10(-6)/K (50-800 degrees C), which increased to 10.46-11.01 x 10(-6)/K when doped with Ag-or Au-content. Such wide CTE (11.01 +/- 0.11 x 10(-6)/K) value matches well with the CTE of ceramic/metallic materials used for high temperature application thus Ag-doped SiO2-MgO-Al2O3-B2O3-K2O-MgF2 glass can be a suitable for high temperature sealing application (like SOFC). (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Virtual Conference on Advanced Nanomaterials and Applications.

Automated summary

This report demonstrates the high temperature sealing tendency of alumino-silicate glasses doped with silver and gold nanoparticles. The glasses were heat-treated to obtain opaque glass-ceramics with fluorophlogopite mica as the main crystalline phase. The presence of nanoparticles changed the microstructure and improved the coefficient of thermal expansion. The Ag or Au-doped glasses are suitable for high temperature sealing applications.