Effect of Substrate Grain Size on Structural and Corrosion Properties of Electrodeposited Nickel Layer Protected with Self-Assembled Film of Stearic Acid.

Amir Hossein Noorbakhsh Nezhad,Reza Arefinia,Ali Davoodi,Saman Hosseinpour,Ehsan Rahimi

doi:10.3390/ma13092052

Amir Hossein Noorbakhsh Nezhad, Reza Arefinia + Show 3 more

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https://doi.org/10.3390/ma13092052

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Abstract

In the present study, the impact of copper substrate grain size on the structure of the succeeding electrodeposited nickel film and its consequent corrosion resistance in 3.5% NaCl medium were evaluated before and after functionalization with stearic acid. Nickel layers were electrodeposited on two different copper sheets with average grain size of 12 and 25 µm, followed by deposition of stearic acid film through self-assembly. X-ray diffraction analysis of the electrodeposited nickel films revealed that the deposition of nickel film on the Cu substrate with small (12 µm) and large (25 µm) grains is predominantly governed by growth in the (220) and (111) planes, respectively. Both electrodeposited films initially exhibited a hydrophilic nature, with water-contact angles of 56° and <10°, respectively. After functionalization with stearic acid, superhydrophobic films with contact angles of ~150° were obtained on both samples. In a 3.5% NaCl medium, the corrosion resistance of the nickel layer electrodeposited on the copper substrate with 25 µm grains was three times greater than that deposited on the copper substrate with 12 µm grains. After functionalization, the corrosion resistance of both films was greatly improved in both short and long immersion times in 3.5% NaCl medium.

Highlights

Hierarchical micro-/nanostructured materials with various shapes and properties are widely used in different applications like as optical materials [1], low adhesive surfaces [2], abrasion-resistant surfaces, anti-icing films [3,4,5,6], anticorrosion coatings [7,8,9], and in the fabrication of superhydrophobic surfaces [10,11]
It could be expected that the Ni electrodeposition process on the D12 substrate led to the formation of an Ni layer with different grain sizes compared to that electrodeposited on the D25 substrate
We examined the impact of copper-substrate-grain size on the micro-/nanostructure, hydrophobicity, and corrosion resistance of succeeding electrodeposited nickel films before and after functionalization with a self-assembled stearic acid film

Summary

Introduction

Hierarchical micro-/nanostructured materials with various shapes and properties are widely used in different applications like as optical materials [1], low adhesive surfaces [2], abrasion-resistant surfaces, anti-icing films [3,4,5,6], anticorrosion coatings [7,8,9], and in the fabrication of superhydrophobic surfaces [10,11]. Numerous methods, including electrodeposition [7,10], chemical-vapor deposition [19], etching [20], electrospinning [21], and sol–gel [1] have been used so far for the fabrication of nickel films that are decorated with micro-/nanostructures. In this regard, electrodeposition is very attractive in comparison with other methods due to its simplicity, ease of control, minimal required material preparation, and relatively cheap equipment [9]. Changes in substrate-surface morphology and the structure of the electrodeposited films were expected to affect the overall corrosion resistance of nickel layers [31,32]

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