Face-Centered Cubic Refractory Alloys Prepared from Single-Source Precursors | JoVE Visualize

Area of Science:

Materials Science
Solid State Chemistry
High-Pressure Physics

Background:

Exploration of face-centered cubic (fcc) structured binary alloys is crucial for understanding material properties under extreme conditions.
Metastable alloys, such as fcc-Ir$_{0.50}$Pt$_{0.50}$ and fcc-Rh$_{0.50}$Pd$_{0.50}$, present unique opportunities for novel material applications.
The synthesis of these alloys from single-source precursors offers a controlled route to achieving desired stoichiometry and structure.

Purpose of the Study:

To synthesize three binary fcc-structured alloys: Ir$_{0.50}$Pt$_{0.50}$, Rh$_{0.66}$Pt$_{0.33}$, and Rh$_{0.50}$Pd$_{0.50}$ using single-source precursors.
To investigate the structural characteristics and compressibility of these alloys under high pressure up to 50 GPa.
To compare experimental findings with theoretical models, specifically the ideal solutions model, for atomic volumes and bulk moduli.

Main Methods:

Alloys were synthesized via thermal decomposition of single-source precursors ([Ir(NH$_{3}$)$_{5}$Cl][PtCl$_{6}$], [Ir(NH$_{3}$)$_{5}$Cl][PtBr$_{6}$], [Rh(NH$_{3}$)$_{5}$Cl]$_{2}$[PtCl$_{6}$]Cl$_{2}$, and [Rh(NH$_{3}$)$_{5}$Cl][PdCl$_{4}$]·H$_{2}$O) in a hydrogen flow below 800 °C.
High-pressure compressibility was studied using diamond anvil cells up to 50 GPa at room temperature.
Structural analysis and determination of bulk properties (atomic volume, bulk modulus) were performed.

Main Results:

All synthesized fcc-structured binary alloys (Ir$_{0.50}$Pt$_{0.50}$, Rh$_{0.66}$Pt$_{0.33}$, and Rh$_{0.50}$Pd$_{0.50}$) were found to be stable under compression up to 50 GPa.
Experimental data for atomic volumes and bulk moduli showed good agreement with the predictions of the ideal solutions model.
Specific Br…Br interactions were identified as influencing the crystal structure arrangement in [Ir(NH$_{3}$)$_{5}$Cl][PtBr$_{6}$].

Conclusions:

The synthesized fcc alloys exhibit remarkable stability under high-pressure conditions, suggesting their potential for applications requiring mechanical robustness.
The ideal solutions model accurately describes the bulk properties of these binary alloys, providing a reliable theoretical framework for future alloy design.
The study highlights the importance of precursor chemistry in controlling alloy synthesis and understanding structure-property relationships.