Thermal behaviour of zircon/zirconia-added chemically durable borosilicate porous glass

Abstract

Macroporous alkali resistant glass has been developed by making additions of zirconia (ZrO 2 ) and zircon (ZrSiO 4 ) to the sodium borosilicate glass system SiO 2 -B 2 O 3 -Na 2 O. The glass was made using a traditional high temperature fusion process. Differential thermal analysis (DTA) was carried out to identify the glass transition temperature (T g ) and crystallisation temperature (T x ). Based on these findings, controlled heattreatments were implemented to separate the glass into two-phases; a silica-rich phase, and an alkali-rich borate phase. X-ray diffraction (XRD) was used to identify any crystal phases present in the as-quenched and heat-treated glasses. Fourier transform infrared (FTIR) spectroscopy also proved effective in investigating phase separation and crystallisation behaviour. After leaching, a silica-rich skeleton with an interconnected pore structure and a uniform pore distribution was observed. Pore characterisation was carried out using mercury porosimetry. The size and shape of the pores largely depended on the heattreatment temperature and time. ZrO 2 /ZrSiO 4 additions increased the alkali resistance of the porous glass 3-4 times.

Glass–Ceramic Foams from Borosilicate Glass Waste

“…The two crystalline phases identified, first cristobalite already starting to show its XRD peaks at 800°C, then sodian wollastonite, are common phases in this compositional range . In particular, the wollastonite crystals developed in the present research are related to the significant CaO content in the parent glass, as observed by Agathopoulos et al .…”

Effect of Zirconium Dioxide in BaO-ZnO-B2O3-SiO2 system on Optical Properties of Color Conversion Glasses

“…[11][12][13] ZrO 2 plays the role of both the forming agent and intermediate agent and Zr 4+ increases bridging oxygen within glass network and thus, the more content of ZrO 2 the higher T g . 14,15) Figure 2 shows refractive index of the glasses depending on variation in the content of BaO and ZrO 2 . It's well known that more content of BaO and ZrO 2 , the higher refractive index.…”

“…It's well known that more content of BaO and ZrO 2 , the higher refractive index. [10][11][12][13][14][15] To increase the refractive index of the glass based on such fact, the content of BaO was increased from 25 mol% to 40 mol% and refractive index of the glass depending on change to the content of ZrO 2 was checked. Consequently, refractive index of the glass when the content of BaO was 40 mol%, was higher than 25 mol%.…”

Improvement of the mechanical and biological properties of bioactive glasses by the addition of zirconium oxide (ZrO2) as a synthetic bone graft substitute

“…In glass networks, ZrO 2 is known to act as a network former to form ZrO 4 structural units and as a modifier in the formation of ZrO 6 structural units 34 . In addition, numerous studies have validated the involvement of ZrO 2 in both the formation of the silicate network and the reconstruction of broken SiOSi bonds by forming ZrOSi bonds that act as intermediates 22,35,36 . Similar to the Si 4+ ion, zirconium has a charge of 4 + ; therefore, it is able to form a tetrahedral glass network with four O 2− ions.…”