Effect of Additive ZrO₂ on Spinodal Phase Separation and Pore Distribution of Borosilicate Glasses

Abstract

Sodium borosilicate porous glasses arising from spinodal phase separation are promising functional materials for separation membranes, enzyme and catalyst supports, and photonic materials. The present paper studied the effect of the additive of ZrO 2 on the spinodal phase separation and pore distribution of the sodium borosilicate glasses using 11 B nuclear magnetic resonance spectrum, 29 Si nuclear magnetic resonance spectrum, mercury measurement, and nitrogen adsorption techniques. The experimental results showed that ZrO 2 inhibited both the initiation process in early stage and the coarsening process in later stage of the spinodal phase separation. The pore volume was found to decrease slightly with the addition of ZrO 2 at the beginning. However, when ZrO 2 content > 7 mass%, the pore volume decreases dramatically with further addition of ZrO 2 . 65% of the pore volume in the sample without addition of ZrO 2 will be lost when the addition amount of ZrO 2 increases from 0 to 10 mass%. The inhibition effect on the pore volume is due to the structural change of boron network by the introduction of ZrO 2 . The oxygen defects, such as oxygen vacancy, which initiates the spinodal phase separation, are reduced during the transformation process from four-coordinated boron to three-coordinated boron by the introduction of ZrO 2 . The growth of the pore size of the sample, which is controlled by the dynamic process of coarsening in the later stage of the spinodal phase separation, is also inhibited by the introduction of ZrO 2 . With the addition of zirconia, the three-coordinated boron with stronger bond energy increases. This may reduce the movement of the oxygen-contained boron groups during mass transfer of the coarsening process of the spinodal phase separation, and consequently inhibit the growth of the pore size.

Network structure and thermal stability study of high temperature seal glass

“…This result means SABS-5 is less stable than SABS-0 but not so unstable as to cause extensive devitrification. 35 Therefore, SABS glass thermal stability decreases as the amount of four-coordinated BO 4 units increases for higher B 2 O 3 content. In addition, the SABS glasses contain La 3+ and Sr 2+ cations, which have a higher tendency to bond with the glass forming cations through nonbridging oxygen atoms than monovalent cations.…”

Comparison between barium and strontium-glass composites for sealing SOFCs

“…In a borosilicate glass, the solubility of ZrO 2 was associated with a structural change in the boron network, retarding phase separation. 7 Similarly, the dissolution of ZrO 2 in our Ba-glass may suppress the nucleation and growth of crystalline phases, explaining the higher temperature for onset of crystallization and crystallization peak observed. The volume fraction of YSZ additive seems to have no influence on these thermal events because the ZrO 2 solubility in the melt is so low that it is saturated even for the lowest amount used.…”

Reintroducing sborgite: Crystallization through exposure of sodium borosilicate glasses to moisture

“…Table 1) were melted in platinum crucible with reagent level Na 2 CO 3 , B 2 O 3 and SiO 2 (Fisher Scientific, USA) following the processing parameters listed in Table 1. The glass melts were air quenched on a stainless steel plate pre-heated at 500 1C, phase separation of both glass were achieved by heat treatment using previously reported methods [9,10]. Heat treatment of glass (1) at 610 1C for 10 h resulted in a phase separated glass with a droplet in matrix microstructure [9] and heat treatment of glass (2) at 600 1C for 24 h resulted in a phase separated glass with a spinodal microstructure [10].…”