Milling-driven nanonization of As S100- alloys from second glass-forming region: The case of lower-crystalline arsenicals (56<x<66)

Competitive intercrystalline phase-transformation and amorphization effects under high-energy mechanical milling are studied in As _xS _100-x alloys from low-crystallinity domain (56< x<66) of the second glass-forming region (51< x <66), employing complementary X-ray powder diffraction analysis, micro-Raman scattering spectroscopy, heat flow differential scanning calorimetry and temperature-modulated multifrequency DSC TOPEM® methods. Milling is shown to activate preferential generation of nanosized monoclinic β-As ₄S ₄ phase in these As _xS _100-x arsenicals at low As content (50< x <60) accompanied by appearance of isocompositional amorphous phase. Principal scenario of milling-driven interphase disproportionality in these arsenicals with high As content (58< x<66) is identified as plastic-crystalline rhombohedral β-As ₄S ₃ phase generation supplemented by extraction of As-rich amorphous substance probably of As ₄S ₂ composition. Appearance of amorphous a-As ₄S ₂ phase with relatively low glass-transition temperature of ~50 °C is supplemented to β-As ₄S ₄ polymorph stabilized along with nanostructured plastic-crystalline nc-β-As ₄S ₃ phase. Temperature-depressing effects of milling on calorimetric heat-transfer processes are revealed in whole compositional domain of the studied nanoarsenicals.