Surface Tension of KPO3-WO3 Melts

What is it about?

The temperatures Tliq of molten xWO3-(1−x)KPO3 mixtures with a molar content between x = 0 and x=0.60 have been determined by differential thermal analysis. The surface tension of the xWO3- (1−x)KPO3 melts in the interval from x = 0 to x = 0.5 has been measured by ring tensiometry for temperatures 10 K- 20 K above the melting points, up to 1373 K. The data obtained for KPO3 were fitted by a linear dependence on the temperature and compared with data available in the literature. The surface tension of the xWO3-(1−x)KPO3 melts was found to decrease non-monotonously with x. Three bends at x ~ 0.15, 0.30, and 0.45 were observed in the surface tension vs. molar fraction curve. The first and the third bends correspond to eutectic compositions; the second one is related to the formation of congruently melting K2WO2P2O7. Equations describing the temperature and concentration dependences of the surface tension are proposed.

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