Direct copper–zinc alloy coatings combining metal-ethylenediaminetetraacetic acid complex solutions and high-heat treatment via hydrogen/oxygen-coupled flame

Alloy films were synthesized using intense hydrogen/oxygen flame heating of an aqueous ethylenediaminetetraacetic acid (EDTA)-(Cu, Zn) (NH 4 ) 2 solution precursor. The substrate type (alumina, A5052, or Si (100)) was varied to control the thermal history. The synthesis of Cu-Zn alloy films from EDTA-(Cu, Zn) (NH 4 ) 2 solution via flame heating is highly sensitive to both the substrate type and the precursor Cu/Zn ratio. Notably, while the substrate affected film composition and oxide formation, increasing the Zn content primarily induced a structural change from dense to porous morphology, without a corresponding dramatic shift in the final alloy's Cu/Zn ratio. The core novelty lies in the synergistic combination of metal-EDTA complexes as a volatile, molecular precursor and the high-intensity, reducing atmosphere of the hydrogen/oxygen-coupled flame for in situ alloying and coating formation. This is a single-step, fast-turnaround process. • Cu-Zn ally films were synthesized on various substrates. • Thermal history was controlled by the substrates. • Changing the Cu/Zn composition ratio affected the film’s composition and morphology.