Synthesis and evaluation of hardness and sliding wear resistance of electrodeposited nanocrystalline Ni–Fe–W alloys

Abstract

The present work involves synthesis, characterisation and evaluation of hardness and sliding wear resistance of electrodeposited nanocrystalline Ni–Fe–W alloys. The crystallite size reduced with an increase in current density owing to an increase in the amount of alloying elements (Fe and W). Ni–Fe–W alloy with 23 at.-%Fe and 1·3 at.-%W plated at 0·1 A cm−2 exhibited the maximum hardness of 563 HV. The alloys exhibited a direct Hall–Petch relation above a crystallite size of 12 nm and an inverse Hall–Petch relation below 12 nm. The wear resistance of the alloys increased with a reduction in the crystallite size in the direct Hall–Petch region and decreased in the inverse Hall–Petch region. Ni–Fe–W coatings with 23 at.-%Fe and 1·3 at.-%W plated at 0·1 A cm−2 exhibited superior wear resistance.

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.…”

“…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.…”

“…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.…”

“…The metallurgical fabrication of these nanostructured alloys is expensive due to tungsten's high melting point. Therefore, other procedures for their production have been developed, such as mechanical alloying, sputtering, or electrolytic deposition from water baths [8][9][10][11][12][13][14][15][25][26][27].…”