INTRODUCTION:

Electrodeposition, also known as electroplating, is a versatile and widely adopted technique for producing dense, uniform, and adherent metal, alloy, and composite coatings. Its popularity stems from several advantages, including low processing temperatures, high-purity deposits, cost-effectiveness, and the ability to coat parts with complex geometries ¹. While the parameters of the electrochemical bath, such as pH, current density, and temperature, are well-studied, recent research has highlighted that the substrate’s inherent characteristics are equally decisive in governing the final properties of the deposited film ².

The influence of the substrate can be categorised into several physical and chemical factors: Surface Structure and Texture, Surface Chemistry and Activation, Roughness and Wettability, Conductivity and Magnetic Properties. This paper investigates the comparative effects of substrate material on the electrochemical performance of coatings ³. Electroplating is a surface modification process in which a metal layer is formed on a solid object using an electrical current. In this process, the substrate to be coated functions as the cathode in an electrolytic system. The electrolyte is a solution containing dissolved metal ions of the coating material. The anode is commonly composed of the same metal or an inert conductive substance ⁴.

When a direct current is applied from an external power source, metal ions migrate toward the cathode, where they gain electrons and are deposited as a uniform metallic coating. The electro part of the system includes the voltage/current source and the electrodes, anode and cathode, immersed in the chemical part of the system, the electrolyte or plating bath, with the circuit being completed by the flow of ions from the plating bath to the electrodes ⁵. The metal to be deposited may be the anode and ionised to go into the electrolyte, or come from the composition of the plating bath. Copper, tin, silver, and nickel metals typically come from anodes, while gold salts are usually added to the plating bath in a controlled process to maintain the bath's composition. The plating bath generally contains other ions to facilitate current flow between the electrodes ⁶. Electrolytic deposition is an electrochemical surface engineering technique in which a solid material is formed on a conductive substrate through electrically driven reduction reactions occurring at the electrode-electrolyte interface ⁷.

The process relies on an externally supplied direct current to transport charged species within an electrolyte and to promote their conversion into a coherent solid layer on the cathode. Because the deposition occurs under carefully regulated electrical conditions, electrolytic deposition offers exceptional control over coating growth, composition, and structural characteristics ⁸. One of the defining strengths of electrolytic deposition lies in its ability to regulate material formation at the atomic and microscopic scale. The deposition rate and quality of the coating are governed by parameters such as applied potential, current density, electrolyte chemistry, temperature, and hydrodynamic conditions. Subtle variations in these factors can significantly influence nucleation behaviour, grain size, surface roughness, and internal stress within the deposited layer. As a result, the technique provides a versatile platform for tailoring surface properties to meet specific functional requirements ⁹. Originally developed for decorative and protective metal coatings, electrolytic deposition has evolved into a critical fabrication method for advanced materials. Modern research demonstrates its effectiveness in producing alloy coatings, multilayer structures, nanocrystalline films, and composite deposits incorporating second-phase particles. These engineered surfaces exhibit enhanced mechanical strength, corrosion resistance, electrical performance, and chemical stability, expanding the relevance of electrolytic deposition across multiple scientific and technological domains ¹⁰.

The adaptability of electrolytic deposition has led to its widespread adoption in fields such as microelectronics, energy storage, catalysis, and biomedical engineering. Thin films produced through this method play a key role in electronic interconnects, battery electrodes, sensors, and implantable devices. Furthermore, the relatively low processing temperature and scalable nature of the technique make it compatible with complex geometries and cost-sensitive manufacturing environments ¹¹. Despite its broad applicability, the electrolytic deposition process is governed by interconnected electrochemical kinetics and mass transport phenomena that can introduce defects if not properly controlled. Issues such as non-uniform thickness, porosity, and compositional inhomogeneity remain active areas of investigation ¹².

Consequently, current research efforts are focused on understanding deposition mechanisms, optimizing electrolyte formulations, and developing environmentally sustainable processes. In light of these considerations, the present work investigates electrolytic deposition with emphasis on copper and stainless-steel electrodes, aiming to establish clear correlations between processing parameters and the resulting coating characteristics. The findings are intended to contribute to the rational design of high-performance electrodeposited materials for advanced applications. As a result, achieving defect-free, reproducible coatings requires a detailed understanding of deposition mechanisms and careful optimisation of processing conditions. Recent research efforts focus on improving process efficiency, developing environmentally benign electrolytes, and enhancing deposit performance through advanced bath formulations and pulse-controlled deposition techniques. Electro-deposition has evolved into a reliable and widely applied technique for enhancing material properties such as corrosion resistance, hardness, and durability. Coatings like nickel, cadmium, and zinc-based alloys play a crucial role in industries such as aerospace, automotive, and marine. While cadmium offers excellent performance, its toxicity necessitates safer alternatives like zinc and nickel alloys. Alloying zinc with iron-group metals improves coating performance in harsh environments.

2. METHODOLOGY:

Electrochemical series, referred to as activity series, is a list that describes the arrangement of elements in the order of their increasing electrode potential values. The series has been established by measuring the potential of various electrodes versus standard hydrogen electrodes (SHE). There are two types of Electrochemical Cells: Galvanic cells (also known as Voltaic cells) and Electrolytic cells ¹³. Galvanic Cell / Voltaic Cell - Chemical energy is transformed into electrical energy in these electrochemical cells. The redox reactions that take place in these cells are spontaneous in nature ¹⁴.

In these electrochemical cells, the anode is negatively charged, and the cathode is positively charged. The electrons originate from the species that undergoes oxidation ¹⁵. Electrolytic cell Electrical energy is transformed into chemical energy in these cells. An input of energy is required for the redox reactions to proceed in these cells, i.e. the reactions are non-spontaneous ¹⁶. Electroplating is widely used in industry and decorative arts to enhance the surface qualities of objects including resistance to corrosion, lubricity, reflectivity, electrical conductivity, and appearance ¹⁵.

This study uses a three-electrode cell setup. The electrode cells feature a positively charged anode, a reference electrode and a negatively charged cathode. Electrons originate from an external source (such as a battery) ¹⁶. The power supply was used to apply the potential for deposition. Digital millimeters were used for current and potential measurements. The electrochemical deposition was carried out at room temperature, and the electrodes were kept in the electroplating solution. Thin films were electrodeposited potentiostatically from an aqueous solution on copper and stainless-steel sheets (1 cm x 1 cm).

Fig. 1: Electrical setup showing the voltmeter–ammeter connections and DC power supply used for electrodeposition studies.

2.1 Preparation of Electrodes:

Preparation of Cu electrode:

A copper sheet of dimensions 1 × 1 cm² was employed as both the working and counter electrode, while a saturated calomel electrode (SCE) served as the reference electrode. Before electrodeposition, the copper substrates were thoroughly cleaned to ensure a contaminant-free surface. The cleaning procedure involved mechanical polishing using fine-grade emery paper, followed by cleaning in analytical-grade acetone (Merck, India) to remove organic impurities. The substrates were then rinsed repeatedly with distilled water and dried under ambient conditions. To define the active deposition area and prevent unwanted electrochemical reactions on the remaining surface, the copper sheet was masked using electrically insulating adhesive tape, exposing only the desired deposition region, shown in Figure 2.

Fig. 2: Copper strips used as substrates

Preparation of stainless-steel electrode:

A stainless-steel sheet with an effective area of 1 × 1 cm² was employed as both the working and counter electrode, while a calomel electrode served as the reference electrode. Before electrodeposition, the stainless-steel substrates were carefully prepared to obtain a clean and uniform surface. The surface treatment involved mechanical polishing using fine-grade emery paper, followed by cleaning with acetone to remove grease and other organic residues. The substrates were subsequently rinsed thoroughly with distilled water and dried under ambient conditions. To confine the electrochemically active region, the non-deposition areas of the stainless-steel sheet were covered with an electrically insulating adhesive tape, leaving only the desired deposition surface exposed, shown in figure 3.

Fig. 3: Stainless Steel strips used as substrates

2.2 Preparation of electrolytes:

Preparation of 0.1 N Electrolyte Solutions

Analytical reagent (AR) grade chemicals were used for the preparation of all electrolyte solutions, and distilled water was employed as the solvent throughout. The required quantities of chemicals were accurately weighed using a digital analytical balance (Mettler, readability ±0.1 mg). Each solution was prepared in a clean and dry 100 mL standard volumetric flask following standard laboratory procedures. Following solutions of strength 0.1 N were prepared:

Cadmium Sulphate:

A 0.1 N cadmium sulphate solution was prepared by accurately weighing 2.085 g of cadmium sulphate (CdSO₄·xH₂O, AR grade, Merck, India) on an analytical balance. The weighed salt was transferred into a 100 mL volumetric flask and dissolved in a small volume of distilled water with gentle swirling. After complete dissolution, the solution volume was made up to the calibration mark with distilled water to obtain a homogeneous solution.

Zinc Sulphate:

For the preparation of 0.1 N zinc sulphate solution, 1.62 g of zinc sulphate (ZnSO₄·7H₂O, AR grade, Merck, India) was precisely weighed using a digital balance. The salt was transferred into a 100 mL volumetric flask and dissolved completely in distilled water. The final volume was adjusted to 100 mL with distilled water, ensuring uniform mixing.

Nickel Chloride:

A 0.1 N nickel chloride solution was prepared by weighing 1.29 g of nickel chloride hexahydrate (NiCl₂·6H₂O, AR grade, Merck, India) using an analytical balance. The compound was dissolved in distilled water in a 100 mL volumetric flask with continuous swirling until a clear solution was obtained. The volume was then made up to the mark with distilled water.

Copper Sulphate:

A 0.1N copper sulphate solution was prepared by dissolving 2.5 g of copper sulphate pentahydrate (CuSO₄·5H₂O, AR grade, Merck, India) in 100 mL of distilled water taken in a 100 mL volumetric flask. The solution was stirred thoroughly to ensure maximum dissolution, resulting in a saturated electrolyte suitable for electrochemical studies.

Cobaltous Chloride:

For cobaltous chloride, 1.29 g of cobalt (II) chloride (CoCl₂·6H₂O, AR grade, Merck, India) was accurately weighed using an analytical balance and transferred to a 100 mL volumetric flask. Distilled water was added gradually, and the contents were mixed until complete dissolution occurred. The volume was finally adjusted to 100 mL with distilled water to obtain a uniform solution.

2.3 Device Setup and Connections used:

The electrochemical device was set up in such a way that the positive terminal of the voltmeter and ammeter were connected to the working electrode with the help of metal clips. The reference electrode was connected to the voltmeter's negative terminal. The positive terminal of the battery was connected to the counter electrode. The negative terminal of the battery and the ammeter were connected, shown in Figure 4.

Fig. 4: Electroplating setup showing the metal anode (+) and cathode (−) immersed in the electrolyte solution

3. RESULT AND DISCUSSION:

The experiment was conducted in such a way that all the connections were accurately done in the experimental setup. Initially, the ammeter and voltmeter readings kept fluctuating in no precise pattern till it reached the plateau, i.e., the current and the potential kept changing for the initial few minutes as soon as the apparatus was passed with current, reported in Table 1. This is the same for all electro-deposition which were carried out, and after it reached the plateau, the voltmeter and ammeter readings were almost constant, which can be seen in the following observations, shown in Figure 5.

Fig.5: Comparative deposition graph

Table 1. Comparative Observation table

Electrode used	Metal substrate Deposited	Electrolyte	Applied Potential (eV)	Deposition Time (min)	Initial Observations	Final Observations
Copper	Zinc	0.1N ZnSO₄	−1.20	40	High voltage fluctuation	Stable deposition after the initial phase
Copper	Cadmium	0.1N CdSO₄	−0.74	60	Fluctuations in current and voltage	Parameters stabilised with time
Copper	Nickel	0.1N NiCl₂	−1.04	40	Initial instability	Deposition observed on the counter electrode
Stainless Steel	Copper	0.1N CuSO₄	−0.34	60	Initial current and voltage fluctuation	Uniform copper coating obtained
Stainless Steel	Cadmium	0.1N CdSO₄	−0.74	45	Rapid voltage fluctuation	Stable deposition achieved
Stainless Steel	Cobalt	0.1N CoCl₂	−0.54	40	Significant initial variations	Readings stabilised over time

3.1 Electrolytic Deposition:

Deposition of Zinc on Copper electrode:

Zinc deposition was carried out on a copper substrate using 0.1 N zinc sulphate (ZnSO₄) as the electrolyte, shown in Figure 6. A constant deposition potential of −1.2 V was maintained throughout the experiment. Initially, significant fluctuations in voltage were observed, whereas the current exhibited comparatively minor variations. With time, both parameters stabilised, indicating steady-state deposition conditions. The total deposition time required was 40 minutes.

Fig. 6: Deposition of Zinc on copper electrode.

Deposition of Cadmium on Copper electrode:

Cadmium was electrodeposited on a copper plate using 0.1 N cadmium sulphate (CdSO₄) electrolyte. A constant potential of −0.74 V was applied. During the initial stages of electroplating, noticeable fluctuations in both current and voltage were recorded. After a certain duration, these fluctuations diminished, and stable readings were obtained, suggesting significant deposition, shown in Figure 7.

Fig. 7: Deposition of Cadmium not shown on copper electrode.

Deposition of Nickel on Copper electrode:

Nickel deposition on copper was performed using a 0.1N nickel chloride (NiCl₂·6H₂O) electrolyte under a maintained potential of −1.04 V. As observed in other systems, both voltage and current showed initial instability before gradually stabilising, shown in Figure 8. A notable observation in this experiment was the occurrence of unintended deposition on the counter electrode, indicating partial dissolution and redeposition phenomena. The total deposition time was 40 minutes.

Fig. 8: Deposition of Nickel on a copper electrode.

Deposition of Cu on Stainless Steel electrode

Copper electroplating was carried out on a stainless-steel substrate using 0.1N copper sulphate (CuSO₄) electrolyte. A deposition potential of −0.34 V was applied. Initial fluctuations in voltage and current were observed, which stabilized after some time. The deposition process was continued for 60 minutes, resulting in a uniform copper coating, shown in Figure 9.

Fig.9: Deposition of Copper on a Stainless-steel electrode

Deposition of Cd on Stainless Steel electrode:

Cadmium deposition on stainless steel was conducted using 0.1 N cadmium sulphate electrolyte at a constant potential of −0.74 V. During the early phase of deposition, voltage fluctuations were prominent, whereas current variations were relatively less pronounced, shown in Figure 10. Stable deposition conditions were achieved with time, and the process was completed in 45 minutes.

Fig.10: Deposition of Copper on Stainless-steel electrode

Deposition of Cobalt on Stainless Steel electrode:

Cobalt electroplating was performed on a stainless-steel substrate using cobaltous chloride (CoCl₂) electrolyte, shown in Figure 11. A constant potential of −0.54 V was maintained. Considerable variations in both voltage and current were observed initially; however, these fluctuations decreased over time, leading to stabilised readings and successful deposition within 40 minutes.

Fig.11: Deposition of Copper on Stainless-steel electrode

4. CONCLUSION:

The study on electrodeposition shows that the type of electrode material and the metal being deposited significantly influence the behavior of deposition and the quality of the coating. When copper was the electrode, the deposition of zinc, cadmium, and nickel displayed clear initial instability, marked by fluctuations in voltage and current, which pointed to rapid electrochemical reactions happening at the surface. Zinc needed the highest applied potential and stabilized after an initial phase, while cadmium's deposition was significant over time. Nickel deposition was less controlled, as metal was deposited on the counter electrode, indicating uneven reduction conditions. In contrast, stainless steel electrodes showed better stability and created more uniform coatings. Copper deposition on stainless steel took place at a lower applied potential and resulted in a smooth, even coating, while cadmium and cobalt deposits stabilized after initial fluctuations. In summary, stainless steel was found to be a more effective electrode material for achieving controlled and uniform electrodeposition, while copper electrodes exhibited higher reactivity, leading to greater initial instability. Overall, electroplating continues to advance as a precise scientific process with significant future potential, and further studies on different substrates and their photoactivity are recommended.

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Received on 18.04.2026 Revised on 16.05.2026

Accepted on 10.06.2026 Published on 04.07.2026

Available online from July 30, 2026

Asian J. Research Chem.2026; 19(4):311-316.

DOI: 10.52711/0974-4150.2026.00048

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