Shear viscosities of galliosilicate liquids

The shear viscosities of 19 galliosilicate and related liquids have been measured using the concentric cylinder method. Nine of the liquid compositions lie in the Na₂O-Ga₂O₃-SiO₂ system, eight liquids correspond in composition to Xⁿ⁺ _1/nGaSi₃O₈ (where X = Cs, Rb, K, Na, Ln, Ba, Sr, amd Ca), and five liquids are Li silicates related by the exchange of Al, Ga, and Fe. The measurements were performed at 1 atm of air pressure in the temperature range of 1700-900°C and a viscosity range of 10^1.3-10⁵ dPaS. The rotation rates ranged from 0.5 to 100 rpm. All melts exhibited Newtonian viscosities. A correlation can be made between liquid viscosity and glassy heat of solution that is similar to that previously noted for the alkali exchange in aluminosilicate melts of the formula XAlSi₃O₈ (where X = alkali). Results confirm galliosilicate liquids as useful analogues for aluminosilicate liquids in studies where the high viscosities of the latter may prevent experimental determination of certain relaxed liquid properties. -from Author