Rational Compositional Control of Electrodeposited Ag-Fe films

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• Electrodeposition of alloys with immiscible components, like Ag-Fe, is challenging due to differing deposition potentials and bath instability.
• Existing methods struggle with thermodynamic and kinetic barriers, leading to poor film quality and composition control.

Purpose of the Study:

• To synthesize thermodynamically immiscible Ag-Fe alloy films.
• To develop a controllable method for Ag-Fe alloy electrodeposition.
• To investigate the electrochemical mechanisms and film properties.

Main Methods:

• Utilized a novel alkaline citrate-dimethylhydantoin (DMH) complex for Ag(I) complexation.
• Incorporated Fe³⁺ to mitigate spontaneous Ag(I) reduction, guided by mixed potential theory.
• Employed mass-transfer coefficient ratio for film composition control.
• Systematically investigated electrochemical reactions using cyclic voltammetry.

Main Results:

• Successfully synthesized uniform, high-quality Ag-Fe alloy films with <4 at.% composition error.
• Demonstrated effective control over film composition by adjusting bath constitution.
• Observed biphasic Ag-fcc and Fe-bcc structures in films deposited at high overpotentials.
• Identified a narrow potential transition range (<0.05 V) for Fe deposition.

Conclusions:

• The novel DMH complex and Fe³⁺ addition effectively enable the electrodeposition of immiscible Ag-Fe alloys.
• The developed paradigm provides precise control over alloy film composition.
• The findings offer a new pathway for fabricating advanced Ag-Fe alloy materials.