Synthesis, structure and properties of nickel-iron-tungsten alloy electrodeposits - part I: Effect of synthesis parameters on chemical composition, microstructure and morphology

Abstract

Kinetic and operational electrolysis parameters determine the polarization characteristics, electrodeposition current efficiency, morphology, chemical composition and microstructure of nickel/iron/tungsten alloy deposits. The alloys electrodeposited at a current density of 50 mAcm-2 to 1000 mAcm-2 contain an amorphous phase and nanocrystals of an FCC solid solution of iron and tungsten in nickel. During annealing at temperatures above 500?C, amorphous phase crystallization, crystalline grain growth of the FCC phase and a reduction in both internal microstrain and minimum density of chaotically distributed dislocations take place in the alloy. Milling the spongy deposit of the alloy causes amorphous phase crystallization, FCC-phase crystalline grain growth, and size reduction and rounding of powder particles. [Projekat Ministarstva nauke Republike Srbije, br. 172057]

Effect of Microstructural Changes during Annealing on Thermoelectromotive Force and Resistivity of Electrodeposited Ni85.8Fe10.6W1.4Cu2.2 Alloy

“…This microstructure is the result of the high electrodeposition current density applied as well as of the presence of iron, copper, and, particularly, tungsten in the FCC crystal lattice of the solid solution of nickel [7][8][9][10][11][12][13][14][15][16][17]35].…”

“…The presence of tungsten, iron, and copper in the FCC solid solution of nickel inhibits crystalline grain growth [7][8][9][10][11][12][13][14][15][16][17]. Tungsten, iron, and copper cause an increase in the mean interatom distance in the FCC phase, resulting in the shift of peak maxima to lower 2 values.…”

“…Nickel/iron alloys have good mechanical, electrical, and magnetic properties and a high catalytic activity for some electrochemical reactions [5][6][7]. Alloying these alloys with small quantities of tungsten improves their thermal stability, wear resistance, corrosion resistance, microhardness, and high-temperature oxidation [8][9][10][11][12][13][14][15][16][17]. NiFeW alloys may exhibit the key properties of NiW and FeW alloys while eliminating the unwanted properties of the two-component alloys.…”

“…Nanostructured coatings and powders of nickel/iron/ tungsten alloys can be obtained by electrolysis from environmentally friendly citrate ammonia solutions [8][9][10][11]16]. Electrolysis can produce alloys that differ in microstructure and, hence, in electrical, magnetic, and mechanical properties, thermal stability, and corrosion resistance from those of the same chemical composition prepared by metallurgy routes.…”

Research into influence of the electrolysis modes on the composition of galvanic Fe-Co-Mo coatings

“…Second, the composition of galvanic deposits, the ratio of components and the phase composition of coatings are essentially affected by the synthesis conditions [9]. In turn, the structure of alloy predetermines the properties and areas of application of coatings.…”