In situ TEM study on electron irradiation effects in SiO₂–Na₂O–B₂O₃ glasses

Abstract

In situ transmission electron microscopy (TEM) was used to study the electron irradiation effects of SiO 2 -Na 2 O-B 2 O 3 (SNB) glasses. Three kinds of SNB glasses were designed and fabricated with constant K (K = [SiO 2 ]/[B 2 O 3 ] molar ratio) and varying R (R = [Na 2 O]/[B 2 O 3 ] molar ratio). The electron irradiation effects were found to be significantly dependent on the value of R. Gas bubbles and small particles were observed in the bright field (BF) images of irradiated SNB glasses with sufficient Na 2 O content. The bubbles are believed to be composed of molecular oxygen O 2 which was formed in the recombination processes of broken non-bridging oxygen (NBO) structures. Irradiation-produced small particles are suggested to be Si-enriched phases which were formed via deconstruction of reedmergnerite groups. The different responses of these three kinds of SNB glasses agree well with their initial structural groups that are theoretically derived from the Bray's model. K E Y W O R D S electron irradiation, in situ transmission electron microscopy, oxygen bubble, Si-enriched phase, SNB glass

Investigating the Influence of Ion Species on the Irradiation-Induced Mechanical Properties of Borosilicate Glass

“…Reviewing the literature indicates that many researchers have studied the mechanical property evolutions of ion-and electron-irradiated borosilicate glass. In order to reveal the underlying mechanisms of this issue, experiments have been carried out to study the microstructure and macrostructure changes of glass after the irradiation [5][6][7][8][9]. The obtained results showed that variations in the mechanical characteristics mainly depended on the ion species [5,[10][11][12].…”

The inhibitory effect of excess calcium ions on the polymerization process of calcium aluminate silicate hydrate (CASH) gel

“…51 Oxygen number R represents the proportion of non-bridging oxygen in the system, which can estimate the bonding degree of Si–O and Al–O skeleton, and it can be seen by combining with the formula that the smaller the value of R is, the worse the connectivity of the aluminosilicate skeleton is. 52 According to Fig. 8(b), the MCL of CASH gels decreases when Ca/Si increases, indicating that the increase of Ca 2+ is not favorable to the polymerization reaction of CASH gels.…”

Molecular Insight into the Formation and Fracture Process of Sodium Aluminosilicate Hydrate Gels

“…The oxygen number R was investigated to estimate the connectivity of the aluminosilicate structure to further characterize the final structure of NASH with different Si/Al ratios. With reference to the relevant silicate glass systems, the formation of the mesh structure shows an “island-group-chain-layered-shelf” variation, and the oxygen number R can estimate the degree of Si–O and Al–O skeleton bonding, which is expressed as follows: R normalO = N normalO / N Si N O is the the number of oxygen atoms in the aluminosilicate skeleton; N Si is the number of silicon and aluminum atoms in the aluminosilicate skeleton; R O is oxygen/(silicon + aluminum).…”