STUDY OF Zn-Ni ALLOY COATINGSMODIFIED BY NANO-AL2O3 PARTICLES INCORPORATION

Malika Diafi,Elhachmi Guettaf Temam,Adaika Mohamed Lakhdar,Brahim Gasmi,Said Benramache

doi:10.12776/ams.v22i3.706

Abstract

Zn–Ni–Al2O3 nano-composite coatings were electrodeposited on mild steel using a novel sol enhanced electroplating method. The effect of alumina sol on the electrodeposition process, and coating properties was investigated using, X-ray diffraction, scanning electron microscopy (SEM), measurement of microhardness and chronoamperometry and electrochemical impedance spectroscopy were studied in a solution of 3% NaCl. The results indicated that the electro-crystallization processes of Zn–Ni and Zn–Ni–Al2O3 were governed by a three-dimensional nucleation process controlled by diffusion. XRD results showed that the phase structure of both alloy and composite coatings was single Ni5Zn21-γ phase, and the addition of alumina sol in the Zn-Ni matrix increases the microhardness, and we note the maximum hardness is obtained for 50 g/L Al2O3. Conversely, these coatings showed smaller crystallite size and Surface of coatings was uniform and compact, the values of Rct and Zw increase, while the values of Cdl decrease with increasing alumina nano-particles content values for the Zn–Ni– Al2O3 alloy clearly confirm the better corrosion resistance.

Highlights

Electroplated binary Zn–Malloys, where metals are an Fe group such as Ni, Co and Fe, exhibit improved properties compared to pure Zn [1,2,3,4,5]
Zn–Ni alloy deposited in electrolyte I, exhibited a crystallite size of 45 nm, whereas the crystallite size of Zn–Ni alloy coating deposited in electrolyte I+50 g·L−1 Al2O3 decreased to 24 nm
4 Conclusion This work represented the electrodeposition and the corrosion behavior of Zn-Ni alloy deposits elaborated in absence or in presence of 30 and 50 g /l of nano-Al2O3 in the acid sulfate bath

Summary

Introduction

Electroplated binary Zn–Malloys, where metals are an Fe group such as Ni, Co and Fe, exhibit improved properties compared to pure Zn [1,2,3,4,5]. The composite coatings had been characterized, morphological (SEM), structural (XRD), and electrochemical properties of the composite coatings had been studied by potentiodynamic polarization and electrochemical impedance spectroscopy in a solution of 3 % NaCl. 2 Experimental 2.1 Coating processes The deposition of Zn–Ni coatings was carried out onto steel substrates under galvanostatic conditions at operating current density of 30 A cm−2 and a temperature of 30°С, the chemical composition of the basic electrolyte of Zn–Ni alloys deposition was given in Table 1 [8].

Results

Conclusion