Face-Centered Cubic Refractory Alloys Prepared from Single-Source Precursors

Abstract

Three binary fcc-structured alloys (fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50) were prepared from [Ir(NH3)5Cl][PtCl6], [Ir(NH3)5Cl][PtBr6], [Rh(NH3)5Cl]2[PtCl6]Cl2 and [Rh(NH3)5Cl][PdCl4]·H2O, respectively, as single-source precursors. All alloys were prepared by thermal decomposition in gaseous hydrogen flow below 800 °C. Fcc–Ir0.50Pt0.50 and fcc–Rh0.50Pd0.50 correspond to miscibility gaps on binary metallic phase diagrams and can be considered as metastable alloys. Detailed comparison of [Ir(NH3)5Cl][PtCl6] and [Ir(NH3)5Cl][PtBr6] crystal structures suggests that two isoformular salts are not isostructural. In [Ir(NH3)5Cl][PtBr6], specific Br…Br interactions are responsible for a crystal structure arrangement. Room temperature compressibility of fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50 has been investigated up to 50 GPa in diamond anvil cells. All investigated fcc-structured binary alloys are stable under compression. Atomic volumes and bulk moduli show good agreement with ideal solutions model. For fcc–Ir0.50Pt0.50, V0/Z = 14.597(6) Å3·atom−1, B0 = 321(6) GPa and B0’ = 6(1); for fcc–Rh0.66Pt0.33, V0/Z = 14.211(3) Å3·atom−1, B0 =259(1) GPa and B0’ = 6.66(9) and for fcc–Rh0.50Pd0.50, V0/Z = 14.18(2) Å3·atom−1, B0 =223(4) GPa and B0’ = 5.0(3).

Magnetic and Transport Properties of New Dual-Phase High-Entropy Alloy FeRhIrPdPt

“…A similar discussion has been found in AuPdAgPtCu, also showing a dual-phase microstructure [ 39 ]. All binary alloys of noble metals (Rh, Ir, Pd, and Pt) with 1:1 composition form fcc [ 40 , 41 ]. Furthermore, many noble metal HEAs (e.g., PdPtRhIrCuNi and PdPtRhRuCe) are reported to be fcc alloys [ 39 , 42 ].…”

[NiEn3](MoO4)0.5(WO4)0.5 Co-Crystals as Single-Source Precursors for Ternary Refractory Ni–Mo–W Alloys

“…The low-temperature preparation of binary alloys from single-source precursors has been studied in a large number of works in the last decade [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Binary alloys can be prepared for a large variety of refractory metals including Pt, Pd, Ir, Rh, and Os.…”

“…The main drawback of this approach is the discrete composition of a single-source precursor which does not allow one to vary the alloy's composition in a broad range. In the last decade, we developed a strategy to access not only binary phases but also ternary and multicomponent alloys with variable compositions using the co-crystallisation of isoformular isostructural coordination compounds [17]. As an example, [Ir(NH 3 ) 5 Cl][OsCl 6 ] was proposed as a precursor for hcp-Ir 0.5 Os 0.…”