Some Regularities of Deposition of an Iron-Tungsten Alloy from Citrate-Ammoniate Solutions

Abstract

The process of the electrochemical deposition of an iron-tungsten alloy is investigated. It is established that, though the solution is prepared on the basis of compounds of Fe(II), stable deposition of dense deposits of the alloy begins only after a larger fraction of these compounds converts into compounds of Fe(III) as a result of oxidation by oxygen of air and anodic oxidation. The parallel evolution of hydrogen is accompanied by the process of incomplete reduction of iron ions. The current efficiency for the alloy in the working conditions exceeds 50%. The content of tungsten in the obtained alloys is weakly dependent on the current density and amounts to nearly 45% (by weight).

Iron–tungsten alloys electrodeposited under direct current from citrate–ammonia plating baths

“…The maximum microhardness was obtained for Fe-W coatings electrodeposited from citrate-ammonia baths operated at 70°С. An important feature of such alloys was their amorphous or nanocrystalline structure [6,[14][15][16][17][18]. The corrosion behavior of such Fe-W coatings was reported by Kublanosky et al [18].…”

“…At least four processes take place during the electrodeposition of Fe-W alloys, namely the reduction of both iron complexes and tungstate ions, the evolution of hydrogen, and the formation of products resulting from the incomplete reduction of iron ions [14][15][16]. Moreover, the current efficiency, the structure, and the morphology of such electrodeposited alloys depend on the cations presented in the electrolyte, namely NH 4 + , K + , and Na + [16].…”

Characterization of FePt film electrodeposited with a ferric electrolyte

“…In their electrolyte, ferric ions are complexed by sorbitol and can be reduced to metallic iron. In the electrodeposition of Fe-W alloy by Zakharov et al [16], the reduction of metal ions occurs most likely from ferric ions, rather than from ferrous ions. This indicates that the FePt bath based on a ferric salt can be an alternative electrolyte to chloride or sulfate baths.…”

Otimização do banho eletrolítico da liga Fe-W-B resistente à corrosão

“…Esse comportamento pode estar associado ao efeito sinergético entre Fe 2+ e o WO 4 2-23 . Um aumento excessivo da concentração de tungstato de sódio provoca uma diminuição da eficiência de deposição e um aumento da taxa de tungstênio no depósito 25 . A concentração de tungstato de sódio mostrou influência estatística na resistência à corrosão do processo (Tabela 4).…”