Partitioning of gadolinium and its induced phase separation in sodium-aluminoborosilicate glasses

Effect of gadolinium on magnetic circular dichroism and electron magnetic resonance of ε-Fe2O3 nanoparticles formed in borate glasses

“…Several authors have shown that the presence of gadolinium favours phase separation in borate glasses [77,78]. Hence, doping with Gd 2 O 3 is expected to provide favourable conditions for the formation of nanoparticles in the glass.…”

“…This can be explained by the fact that this feature predominantly arises from Fe 3+ ions diluted in the glass matrix while MCD is mainly due to these ions incorporated into magnetically ordered nanoparticles. Low solubility of Gd 2 O 3 in glasses, in particular, in borate glasses has been shown using different experimental techniques [77,79,80]. For instance, for gadoliniumcontaining borosilicate glasses the following model of Gd 3+ partitioning was suggested: firstly, Gd 3+ ions substitute B 3+ in very low quantity; then Gd 3+ begins substituting Si 3+ , and finally Gd 3+ ions aggregate, so that their crystallization can occur [77].…”

“…Low solubility of Gd 2 O 3 in glasses, in particular, in borate glasses has been shown using different experimental techniques [77,79,80]. For instance, for gadoliniumcontaining borosilicate glasses the following model of Gd 3+ partitioning was suggested: firstly, Gd 3+ ions substitute B 3+ in very low quantity; then Gd 3+ begins substituting Si 3+ , and finally Gd 3+ ions aggregate, so that their crystallization can occur [77]. Such behaviour is usually observed for Gd 2 O 3 contents lower than 1% [77][78][79]81].…”

“…For instance, for gadoliniumcontaining borosilicate glasses the following model of Gd 3+ partitioning was suggested: firstly, Gd 3+ ions substitute B 3+ in very low quantity; then Gd 3+ begins substituting Si 3+ , and finally Gd 3+ ions aggregate, so that their crystallization can occur [77]. Such behaviour is usually observed for Gd 2 O 3 contents lower than 1% [77][78][79]81]. Thus, the hypothesis that in iron-and gadolinium-containing glasses the main part of Gd 3+ ions are incorporated in the nanoparticles, substituting Fe 3+ ions in the most "spacious" O1 sites, see Section 3.3, seems quite reasonable.…”

Crystallization behavior of iron‐ and boron‐containing nepheline (Na2O·Al2O3·2SiO2) based model high‐level nuclear waste glasses

“…The composition is per‐alkaline and has been designed to make it similar to typical US HLW glass compositions. The chosen baseline composition is expected to be homogeneous (no phase separation) based on a criterion reported by Qian et al for aluminoborosilicate glasses where the ratio of their excess alkali content, Na 2 O ex ([Na 2 O]–[Al 2 O 3 ]) – to – [B 2 O 3 ], that is, [Na 2 O ex ]/[B 2 O 3 ] decides their homogeneity. Based on this criterion, alkali aluminoborosilicate glasses with [Na 2 O ex ]/[B 2 O 3 ] >0.5 have minimal tendency toward phase separation.…”