Pressure-induced solidifications of liquid sulfur below and above λ-transition

Abstract

Two kinds of glassy sulfurs are synthesized by the rapid compression method from liquid sulfur at temperatures below and above the λ -transition point. The glassy sulfur has different colors and transparencies, depending on temperature, which may inherit some structural information from the λ -transition. Raman spectrum studies of these samples show that a large fraction of polymeric chains exist in the glassy sulfur, even in the one solidified from T < T λ . We find that a higher compression rate instead of a higher temperature of the parent liquid captures more polymeric chains. Pressure-induced glassy sulfur presents high thermal stability compared with temperature quenched glassy sulfur and could transform into liquid sulfur directly without crystallization through an abnormal exothermic melting course. High energy x-ray diffraction is utilized to study the local order of the pressure-induced glassy sulfur.

Chain Breakage in the Supercooled Liquid - Liquid Transition and Re-entry of the λ-transition in Sulfur

“…7(a) . From this point of view, we propose that pressure affects the content of the polymeric chains in amorphous sulfur during the fast compression process, which has been reported in our earlier work 28 . The polymeric content decreases in a systematic and directional way at temperatures higher than 391 K. This temperature matches the melting temperature suggested by XRD results.…”

“…Co. of China Medicine Group) was heated to 453 K (above the ambient pressure λ-transition temperature) inside a piston-cylinder apparatus, and then rapidly compressed to 2.3 GPa within 20 milliseconds. Details of the amorphous sulfur preparation have been reported elsewhere 28 . The crystal sulfur and quenched amorphous sulfur were also analyzed for comparison.…”

A Study of the Pressure-Induced Solidification of Polymers

“…Sulfur is known as a living polymer. Liquid sulfur displays a reversible polymerization transition at around 432 K, which has been interpreted as a kinetically controlled equilibrium reaction between small cyclic monomer molecules and polymeric sulfur molecules [19]. The rapid compression experiment of sulfur melt obtained bulk amorphous sulfur ( a -S).…”

Metastable phase separation and rapid solidification of undercooled Co 40 Fe 40 Cu 20 alloy

“…The liquid phase separation phenomena have been extensively studied [1][2][3][4][5] and their significant effect on structures and properties of various materials have been revealed. [6][7][8][9][10][11][12][13] As the great potential application of high entropy alloys and bulk metallic glasses, liquid phase separation is attracting more and more attention. [14,15] It is interesting that some peritectic and eutectic alloys characterized by a large positive enthalpy of mixing and a nearly flat liquidus curve show a miscibility gap in the metastable undercooled liquid, such as Co-Cu [16] and Fe-Cu.…”