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

N Cirovic,P Maskovic,L Ribic-Zelenovic,M Spasojevic,P Spasojevic

doi:10.2298/sos1503347c

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.

Highlights

Nanostructured materials find wide applications in advanced technologies due to their specific properties [1]
The conclusions presented in this paper provide an explanation of why the chemical composition and phase structure of the deposits obtained in the current density range of 500 mA cm-2 < j < 1000 mA cm-2 do not depend on current density
The results show that an adequate choice of kinetic and operational parameters of electrodeposition, annealing temperature and milling time can result in nickel-iron-tungsten alloys with predefined chemical compositions, microstructures and morphologies

Summary

Introduction

Nanostructured materials find wide applications in advanced technologies due to their specific properties [1]. Nanocrystalline nickel-iron-tungsten alloys have good electrical, magnetic and mechanical properties, high thermal stability and high corrosion resistance [211], and their use for a wide range of industrial applications, mostly as materials for microelectronics and microelectromechanical systems. The metallurgical fabrication of nickel-iron-tungsten alloys is very expensive due to high energy consumption. These alloys have been obtained by electrochemical methods from environmentally friendly citrate ammonia solutions without any environmental and health risks [2,5,10,11,12,13]. The electrochemical process can result in alloys featuring different phase structures and morphology and different mechanical, electrical, catalytic and corrosion properties, their chemical composition is the same as that of

Objectives

Results

Conclusion