Mechanical and Morphological Characteristics of Nickel, Chromium and Nitride-Based Coatings Formed via Electrodeposition and Magnetron Sputtering Techniques on Mild Steel. An Overview

Review Article

Austin Chem Eng. 2023; 10(3): 1104.

Mechanical and Morphological Characteristics of Nickel, Chromium and Nitride-Based Coatings Formed via Electrodeposition and Magnetron Sputtering Techniques on Mild Steel. An Overview

Jahanzeb Bhatti1*; Ali Dad Chandio1; Quazi MM2; Bashir MN3; Rizwan M1; Iftikhar Ahmed Channa1; Abdul Rauf Jamali4; Fayaz Hussain Katper5; Imran Ali6

1Department of Metallurgical Engineering, NED University of Engineering and Technology, Pakistan

2Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang, Pekan, Pahang, Malaysia

3National University of Sciences and Technology (NUST) Islamabad, Pakistan

4Department of Materials Engineering, NED University of Engineering and Technology, Karachi

5Modeling Evolutionary Algorithms Simulation and Artificial Intelligence, Faculty of Electrical & Electronics Engineering, Ton Duc Thang University, Vietnam

6Institute of Metal Research, Chinese Academy of Science, Shenyang, China

*Corresponding author: Jahanzeb Bhatti Department of Metallurgical Engineering, NED University of Engineering and Technology, Pakistan. mail: engineerjahanzeb@gmail.com

Received: July 18, 2023 Accepted: September 15, 2023 Published: September 22, 2023

Abstract

Mild Steel (MS) is considered as the most widely employed engineering material, which is primarily being used in an automotive industry. Several parts including fuel system, outer and body panel, trims, chassis exhaust, along with many other parts are made up of MS. The driving force behind versatility of MS is its unique set of characteristics. However, the issues arise when its tribological degradation occur that creating problems in service conditions. The best solution for this problem is to coat the mild steel with transition metal-based nitride coatings such as, Ni and Cr. Insufficient Literature is available related to the mechanical performance of single/gradient layer (Ni, Cr) N ternary coating on mild steel substrate. Current review focuses on the characteristics of the coatings that are deposited through two different deposition techniques; electrodeposition and magnetron sputtering. The studied coatings materials are nitrides of nickel and chromium, deposited in several layers. Furthermore, the structural and mechanical properties of these coatings have been compared.

Keywords: Structural properties; Mechanical properties; Electrodeposition; Magnetron sputtering; Nitride formation

Introduction

The current growth in the automotive, biomedical, and aerospace and a variety of processing industries demand materials exhibiting improved mechanical performance under severe operating conditions. Mild steel has served as the most integral part of these industries for few decades, owing to its ductility, formability, weldability and reasonable mechanical strength [1,2].

However, monolithic materials are unable to fulfill the synergistic demands of special applications. Here comes the role of surface engineering, which offers enhancement in tribological and mechanical characteristics of conventional materials. This is the reason why so many researchers have focused in recent years to tailor the surface characteristics using several coating techniques. These coatings enhance the tribological performance along with corrosion resistance by serving as an interface between working environment and the substrate [3-5].

Currently various coating techniques have been employed successfully amongst which Electrodeposition (ED) and Physical Vapor Deposition (PVD) are considered as the most prevailing procedures to acquire enhanced hardness, adhesion strength of coating-substrate, control of chemical composition, good surface finish [6-9]. Electrodeposition (ED) mainly sub-divided with respect to bath composition and working parameters. In ED, Watt’s bath is considered as the simple, more controlled and economical deposition method. Whereas in Physical Vapor Deposition (PVD,) the most efficient technique is magnetron sputtering having better coating adhesion to substrate, good control of the temperature and composition, lower thermal shock [10] and ability to use a number of target materials [11].

Significant research interest has been received by automotive industries for the enhancement of mechanical/ tribological properties using metal (such as Al, Ti, Mg, Ni & Cr) transition nitrides as coating materials. Amongst monolithic materials, transition metallic nitride coatings such as nickel, chromium and nitrogen seem to have comprehensive and better properties for automotive and decorative applications [5,12-15]. Due to its attractive properties such as, magnetic properties, toughness, corrosion resistance, wear resistance and hardness, Nickel has received spike in research attention [16,17], and is employed widely as corrosion resistant deposition material [7]. For this purpose, nickel electroplating is more convenient technique [18]. Besides Ni, binary compounds of transition metals (such as Cr N, TiN and NiN etc.) have been used in automotive sector for various applications. CrN is considered as the most suitable coating material from this family. Basic research has been done on physical and mechanical properties of these thin films and give evidence that they possess extremely high hardness, high temperature resistance to oxidation, wear and fatigue resistance, low coefficient of friction [19-24], and good surface finish [25-28]. PVD or more favorably reactive magnetron sputtering is employed most commonly, in order to deposit CrN coating [29]. Several researchers have attempted to improve overall coating properties through various possibilities, for instance single layer [30], bilayer [22], and gradient layer [31-34]. In order to improve wear and corrosion resistance, single layer coatings are commonly deposited on biomedical implants and cutting tools [21] and are very easy to form without incorporating and adjusting phase formation. Bilayers and gradient coating tends to sustain much residual stresses with better corrosion resistant, mechanical and tribological properties, higher resistance to cohesive and adhesive crack propagation as compared to single layer, moreover they possess very fine grain size and almost free of micro cracks and many other defects [35]. So, the combinatorial effect of bilayer electrodeposition and magnetron sputtering provides better coating, superior to individual technique.

Catastrophic coating failure can be avoided by preparing a hybrid system of materials comprising of a harder superficial layer on a tougher coating material [25]. Till date, the effect of combining Ni & Cr has not been studied adequately. The development of CrNiN thin film was carried out using unbalanced magnetron sputtering (closed field) for the components critical for safety [36], magnetic layers [37] and for applications related to cutting tools [38]. However, scarce literature is available, comparing mechanical performance of the single and gradient layer (Ni, Cr) N ternary layer deposited on the mild steel substrate. This study is aimed at reviewing the mechanical performance enhancement of the mild steel substrates using (Ni, Cr) N ternary layer.

A comparative evaluation of the mechanical performance (surface hardness, film-to-substrate adhesion friction coefficient and roughness) is carried out in this review, in relation to the composition and morphology of the (ED Ni) single layer, (ED Ni + magnetron sputtering CrN) bilayer, (PVD CrNiN) single layer and (PVD Ni/NiN/ Cr/CrN/NiCrN) gradient layers deposited on the MS substrate.

Materials for Automotive Industry

Advancement and development in automotive industries is being carried out for 100 years. Time by time extensive features and performance has been developed. As the time goes by, automotive industry is also growing its demands as per requirement. There are so many reasons to introduce and develop new techniques in an automotive industry. As for controlling of harmful gases from combustion engine, engine management and post treatment expertise follow the principles of some international standards, for instance, European Standard EURO III, American EPA Emission Standards, including CAFÉ standards, and Californian Emission Standards.

Beside that ‘‘Organization Internationale des Constructeurs d’Automobiles’’ (OICA) stated that round about 20 million commercial vehicle and about 53 million cars were produced in the year 2007. In fact, automotive industry is facing many challenges due to environmental factor, quality, reliability, life, functionality, safety, economy and many other factors that would be hard to maintain by keep on improving technical properties. As one of the possibilities to improve the engine efficiency is to reduce the weight of the engine components. For this lighter material may perform better, that are also widely being used just like, Al, Ti, and Mg, are the best materials for an automotive industry. But the problem is that, these materials have poor tribological properties [36-38].

There is a wide range of materials being used in an automotive industry since decades. Different materials are used for different applications and selection of material is very important and difficult task as well. Importance of factors in selecting proper material for automotive design and engineering is shown in Table 1. It is seen that importance of cost reduction, weight reduction, easier manufacturing, better durability, integrated functionality is at the top priority in choosing materials. The rest factors also have the importance level within the range, 50-60% [39].