Effect of Electrodeposition Parameters on the Composition and Surface Topography of Nanostructured Coatings by Tungsten with Iron and Cobalt

Abstract

The electrodeposition of binary and ternary coatings Fe-W and Fe-Co-W from mono ligand citrate electrolyte has been investigated. The Fe-Co-W coatings were formed from electrolytes, which composition differs in the ratio of the concentrations of the alloying components and the ligand content. The investigation results indicate a competitive reduction of iron, cobalt and tungsten, the nature of which depends both on the ratio of electrolyte components, and electrolysis parameters. The effect of both current density amplitude and pulse on off time on quality, composition and surface morphology of the galvanic alloys was determined. Coatings deposited on a direct current with a density of more than 6.5 A/dm 2 , crack and peel off from the substrate due to the inclusion of Fe (III) compounds containing hydroxide anions. The use of non-stationary electrolysis allows us to extend the working range of current density to 8.0 A/dm 2 and form electrolytic coatings of sufficient quality with significant current efficiency and the content of the refractory component. The presence of the Co 7 W 6 , Fe 7 W 6 , α-Fe, and Fe 3 C phases detected in the Fe-Co-W deposits reflects the competition between the alloying metals reducing from hetero-nuclear complexes. The surface of binary and ternary coatings is characterized by the presence of spherical agglomerates and is more developed in comparison with steel substrate. The parameters Ra and Rq for electrolytic alloy Fe-W are of 0.1, for Fe-Co-W are 0.3, which exceeds the performance of a polished steel substrate (Ra = 0.007 and Rq = 0.010). These properties prospect such alloys as a multifunctional layer are associated with structural features, surface morphology, and phase composition.

Co-TiO2 Nanoparticles as the Reinforcement for Fe Soft Magnetic Composites with Enhanced Mechanical and Magnetic Properties via Pulse Electrodeposition

“…In this condition, the amount of Fe increased in the deposit. According to the literature [21][22][23], higher current densities enhanced the diffusion of Fe to the coating and as a consequence enhanced the magnetic properties.…”

Corrosion and Mechanical Properties of the Fe‐W‐Wo2 and Fe‐Mo‐MoO2 Nanocomposites

“…At the same time, Fe-W-WO 2 composites are characterized by a higher microhardness in comparison with molybdenum-containing ones due to the presence of tungsten as well as a higher content of oxide hardening phase in the coatings, as evidenced by the higher oxygen content in the tungsten-containing thin films [30,31]. e results obtained for the microhardness indicators of coatings containing tungsten and molybdenum correlate with the data obtained for similar coatings by other researchers [32], which confirms the correctness of the studies performed.…”

The Influence of Sodium Tungstate Concentration on the Electrode Reactions at Iron–Tungsten Alloy Electrodeposition

“…Moreover, the evaluation of species distribution could help understand the compositional variation within the coating thickness and increase (or decrease) in cathodic current efficiency of the process [22]. Moreover, heterometallic species with enhanced molecular mass can be formed in the electrolyte [23,24], whose stability constants are not yet identified. Furthermore, depending on pH and electrodeposition potential, the specific adsorption of citrate anions and the catalytic transformation of citrate accompanied by decarboxylation and electron transfer to the electrode surface followed by further reduction of the adsorbed species has been observed [25,26].…”