Decomposition of single-source precursors under high-temperature high-pressure to access osmium-platinum refractory alloys

Yusenko KV, Spektor K, Khandarkhaeva S, Fedotenko T, Pakhomova A, Kupenko I, Rohrbach A, Klemme S, Crichton WA, Dyachkova TV, Tyutyunnik AP, Zainulin YG, Dubrovinsky LS, Gromilov SA

Abstract

Thermal decomposition of (NH4)2[OsxPt1-xCl6] as single-source precursors for OsePt binary alloys hasbeen investigated under ambient and high pressure up to 40 GPa. Thermal decomposition of mixedmetal(NH4)2[OsxPt1-xCl6] precursors in hydrogen atmosphere (reductive environment) under ambientpressure results in formation of b-trans-[Pt(NH3)2Cl2] and a-trans-[Pt(NH3)2Cl2] crystalline intermediatesas well as single and two-phase OsePt binary alloys. For the first time, direct thermal decomposition ofcoordination compound under pressure has been investigated. A formation of pure metallic alloys fromsingle-source precursors under pressure has been shown. Miscibility between fcc- and hcp-structuredalloys has been probed up to 50 GPa by in situ high-pressure X-ray diffraction. Miscibility gap betweenfcc- and hcp-structured alloys does not change its positions with pressure up to at least 50 GPa.