Milling-driven nanonization of AsxS100-x alloys from second glass-forming region: The case of higher-crystalline arsenicals (51

Abstract

Nanonization accompanied by amorphization processes driven by high-energy mechanical milling are studied in AsxS100-x alloys from higher-crystallinity domain (51<x<56) employing multiexperimental approach.Principal disproportionality in these arsenicals under milling comprises molecular-to-network transformations resulting in β-As4S4 polymorph supplemented by isocompositional amorphous phase. Nanosized state is signalized in broadened Raman-active bands of β-As4S4 crystallites (~40–50 nm), the milling-driven nanonization being accompanied by disappearing of other crystalline phases (pararealgar, χ-phase As4S4, low-temperature dimorphite α-As4S3). At high As content in studie alloys, milling facilitates disappearing of low-temperature α-As4S3 at cost of nanosized high-temperature β-As4S4 and α′-As4S3 phases. These transformations are clarified with heat capacity measurement showing depressing and splitting trend in melting and interphase-transition temperatures from normal-crystalline α′-As4S3 to plastic-crystalline β-As4S3. Intermediate-range ordering of the amorphized AsS phase is enhanced under milling, this phase dominating in network derivatives from As4S4 cage-like molecules, while generation of competitive As-rich phase being expected at higher As content.