Thermodynamics of Bi2O3-SiO2 system

Abstract

Thermodynamic properties of the liquid Bi 2 O 3 -SiO 2 solutions were determined from the results of the electrochemical measurements by use of the solid oxide galvanic cells with YSZ (Yttria-Stabilized-Zirconia) electrolyte. Activities of Bi 2 O 3 in the solutions were determined for 0.2, 0.3, 0.4, and 0.5 SiO 2 mole fractions in the temperature range 1073-1293 K from measured electromotive force (e.m.f) of the solid electrolyte galvanic cell:Bi, Bi 2 O 3 -SiO 2 | YSZ | air (p O2 = 0.213 bar) Additionally, heat capacity data obtained for two solid phases 6Bi 2 O 3 ·SiO 2 and 2Bi 2 O 3 ·3SiO 2 were included into optimization of thermodynamic properties of the system. Optimization procedure was supported by differential thermal analysis (DTA) data obtained in this work as well as those accepted from the literature. Using the data obtained in this work, and the information about phase equilibria found in the literature, binary system Bi 2 O 3 -SiO 2 was assessed with the ThermoCalc software.

Viscosities and working region predictions for bismuth aluminoborosilicate glasses

“…Twenty gram batches were heated in a platinum crucible at 50°C steps for 30‐minutes intervals in the range of 650‐1050°C for compositions with 40 mol% SiO 2 and 650‐1000°C for all other glasses. This heating process moderated the interaction of batch powders (with liquidus temperatures for Bi 2 O 3 ‐B 2 O 3 , Bi 2 O 3 ‐SiO 2 , and Bi 2 O 3 ‐Al 2 O 3 systems at 646, 870, and 1075°C, respectively), producing complete dissolution of powder precursors and resulting in much more uniform colors in solid samples. Portions of each melt were poured into pre‐heated stainless‐steel molds (pre‐heated at 350°C for 30 minutes to prevent sample cracking during the pour) for viscosity sample preparation while the remnant was poured onto a stainless‐steel plate.…”

Primary Crystals of AlfeMnSi Intermetallics in the Cast AlSi Alloys

“…They arise in the polyphase eutectics in a typical shape of the Chinese script. However, in some range of the chemical composition, the massive particles of the AlFeMnSi phases form directly in the liquid alloy through incongruent solidification, before α-Al solid solution crystallization begins [2][3][4][5][6][7] (Fig. 1).…”

“…In this work, a common effect of the Fe/Mn ratio and the cooling rate on shape and crystal structure of the primary AlFeMnSi intermetallic phases will be considered in both hypo-and eutectic AlFeMnSi alloys in a range of concentration of transition metals examined before in slowly cooled alloys in works [2,3,6,7].…”