Electrodeposition and Characterization of Nanocrystalline Ni-Fe Alloys

Abstract

Nanocrystalline Ni-Fe deposits with different composition and grain sizes were fabricated by electrodeposition. Deposits with iron contents in the range from 7 to 31% were obtained by changing the Ni2+/Fe2+mass ratio in the electrolyte. The deposits were found to be nanocrystalline with average grain size in the range 20–30 nm. The surface morphology was found to be dependent on Ni2+/Fe2+mass ratio as well as electroplating time. The grains size decreased with increasing the iron content, especially in case of short time electroplating. Increasing the electroplating time had no significant effect on grain size. The microhardness of the materials followed the regular Hall-Petch relationship with a maximum value (762 Hv) when applying Ni2+/Fe2+mass ratio equal to 9.8.

NiFe/(Ni,Fe)3S2 Core/Shell Nanowire Arrays as Outstanding Catalysts for Electrolytic Water Splitting at High Current Densities

“…With further increase of Fe precursor to 15%, the product crystalline phase shifts from Ni (FCC) to Fe (BCC), in good agreement with literature finding . The grain size, estimated with the Scherrer equation as a measure of product crystallinity, decreases with increasing Fe loading, 14.6, 14.3, 7.9, 7.3, and 6.5 nm for 0, 2.5, 5, 10, and 15% Fe precursor products, respectively . Figure S4 (Supporting Information) shows the composition of the NiFe NWAs estimated with EDX measurements.…”

“…[47] The grain size, estimated with the Scherrer equation as a measure of product crystallinity, decreases with increasing Fe loading, 14.6, 14.3, 7.9, 7.3, and 6.5 nm for 0, 2.5, 5, 10, and 15% Fe precursor products, respectively. [48] Figure S4 (Supporting Information) shows the composition of the NiFe NWAs estimated with EDX measurements. Evidently, because of the anomalous deposition effect of Fe, the molar ratios of Fe in the product nanowires are much higher than the molar ratios of Fe in the corresponding electrolytes.…”

Electrocatalysts for Water Electrolysis

“…The Ni-Fe alloy consisted of 96% Ni, 3% Fe and 1% O, and the binary Ni-Mo alloy had the following composition: 65% Ni, 33% Mo, 2% O. The Ni-Mo-Fe ternary alloy contained 46% Ni, 49% Mo, 1% Fe, and 4% O [109]. The Ni-Mo-Fe ternary compound showed high corrosion resistance in seawater (1.7•10 -3 mm/year) and low overvoltage with hydrogen evolution (-850 V), which leads to rise in its release rate.…”

Experimental design for modelling and multi-response optimization of Fe–Ni electroplating process

“…The authors pointed out that sulfur content of the deposits from the Ni sulfamate bath increased with the pH of the electrolyte and decreased at an elevated temperature of electrolyte up to 60 • C. Also it was concluded that by increasing pH of the electrolytes from 1 to 3.5, the current efficiency, grain size and stresses in the deposits increased accordingly. From the work of Abdel-Karim et al (2011) it was concluded that: (1) by decreasing the Ni 2+ /Fe 2+ mass ratio in the bath, the iron content in the deposits decreases; (2) the increasing of iron content in the bath led to formation of well-defined nodular particles with finer size; (3) the increasing of electroplating time had no significant effect on particle size, (4) nanocrystalline electrodeposited Fe-Ni alloys are composed mainly of two phases: Ni (ss) phase and Ni 3 Fe phase; (5) high hardness values were detected for higher iron content in the deposits (Abdel-Karim et al, 2011).…”