Inferring bubble volume fraction in a glass melt through in situ impedance spectroscopy measurements

Abstract

Bubbled materials can be considered a limiting case composite. 1,2 This low-density phase may be either beneficial or not, depending on its characteristics and the final material application. This phase usually has a detrimental effect when mechanical or corrosion behaviors are considered. On the other hand, these gaseous inclusions usually decrease the thermal and electrical conductivities of solid and liquid materials.Hence, for insulating systems, these composite materials are considered a useful option. In terms of glass/melt engineering processes, bubbles may affect the overall electrical conductivity of a glass bath, 3 and the direct induction process could also be affected 4 because bubbles may negatively affect the thermal and electrical conductivities, resulting in low efficiency and elevated costs.These bubbled materials have been investigated for decades using several experimental methods. To study a population of bubbles, for example, different techniques have been applied so far. Microscopic techniques have been applied to

Rheology of a sodium‐molybdenum borosilicate melt undergoing phase separation

“…Some studies have used impedance spectroscopic methods at high temperature to infer the fractions of bubbles and crystals that form. 33,34 However, this in situ estimation has never been achieved for the system under scrutiny here. For a similar system (containing 2 mol% MoO 3 ) and using X-ray diffraction coupled with Rietveld refinement, Nicoleau et al 29 estimated that the droplet volume was 0.9 vol.%.…”

A feedback mechanism between crystals and bubbles in a RuO2-bearing melt

“…In this latter case, the crystal-rich plug noted above promotes gas accumulation in pockets, as so-called slugs. Pereira et al (3,4) studied an equivalent crystal-free system. There, no bubble accumulation was observed at the free surface of the crucible and bubble dynamics were mainly controlled by the viscosity of the liquid phase.…”

“…(2) Bubbles affect different properties of silicate melt bodies, such as bulk viscosity, density, and electrical conductivity. (2,3) Conversely, silicate melt properties, such as viscosity, dissolved gases, and the presence of crystals may influence bubble dynamics. (4-6) These solid crystalline inclusions can be found in melts in both in industry and in nature.…”

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

“…Over the past few decades, extensive research has been carried out on eliminating bubbles within glass for glass-to-metal seals [13,14]. Following the work by Peitl et al [15], crystallization-induced bubbles need to be considered for designing and manufacturing low porosity glass.…”

“…Following the work by Peitl et al [15], crystallization-induced bubbles need to be considered for designing and manufacturing low porosity glass. Although bubbles in the local region can be reduced using the doping method [14,16,17], the density of sealed glass is still far from the impressive high density of other kinds of glasses that have ultralow porosity [18,19]. The casting-machining (CM) method is one of the most commonly used methods owing to its simple processability [20] and effectiveness in reducing deleterious bubbles.…”