Electroplating | Definition, Principle, Process And Uses

Electroplating refers to the process of coating a metal onto another metal or alloy with the help of an electric current. It is also known as electrochemical deposition or electrodeposition.

Let’s learn the electroplating process in detail, including its working principle, advantages, examples and uses.

Electroplating Definition

Electroplating is a process of coating or plating a metal onto another by hydrolysis It is usually done to avoid metal corrosion or for ornamental purposes.

The setup of Electroplating involves the following components:

• Anode: The metal to be used for coating
• Cathode: The metal on which coating is to be done.
• Electrolyte: It should be the aqueous salt solution of anode metal.
• Power Source: Usually DC supply

For instance, Electroplating is done with a brine or acidic or basic or metal salt solution, a battery, wires, and alligator clips that hold carbon rods attached to the metal to be electroplated and the metal to be stacked in an electroplating device.

Electroplating Principle

Electroplating is based on the principle that,

When two metals acting as electrodes are immersed in the salt of anode metal and a potential difference is created between them by supplying current, then the metal on the anode oxidizes and dissolves into the electrolyte salt and later gets reduced and deposit itself as a thin layer on the metal on cathode.

Electroplating Process

The working principle of Electroplating can be better understood by the following example:

• Let’s take an example of a gold coating.
• In this instance, a layer of gold is to be electrodeposited on metallic jewelry to enhance its appearance. 
• The gold plate is connected to the anode (positively charged electrode) of the circuit and the jewelry on which coating is to be done is kept at the cathode (negatively charged electrode).
• Both are kept immersed in a highly developed electrolytic bath (solution) of gold.
• At this stage, a power source is connected which creates a potential difference between the two electrodes, and current starts flowing from the anode which oxidizes the gold atoms from the anode and dissolves them into the solution.
• These dissolved atoms later get reduced and get deposited on the jewelEry connected to the cathode.

Thus by the above process, the jewelry gets a thin layer of gold on it which is chemically bonded and won’t be removed easily. However, continuous exposure of it to the atmosphere will degrade the layer.

Chemical reactions occur when an electric current passes through a conducting solution. This is called the chemical effect of electric current. Following are some of the chemical consequences of electric current:

• Due to redox reaction, metal gets depleted from one electrode and deposited on other
• Bubbles can form at the electrode due to the evolution of gas
• Color of the solution can change due to displacement reaction.

Learn More :

• Chemical Effect of Electric Current

Factors Affecting Electroplating

These are the factors affecting elctroplating:  

• Current-Voltage level.
• Electrolyte bath’s temperature and chemical makeup.
• Amount of time that has passed.
• Distance between the cathode and the anode is the distance between the cathode and the anode.

Electroplating Types

Various types of Electroplating process are,

1. Chromium Plating is the process of electroplating chromium onto a metal item.
2. Tin Plating is the process of electroplating tin onto a metal item generally iron.
3. Nickel Plating is the process of electroplating nickel onto a metal item.
4. Silver Plating is the process of electroplating silver onto a metal item.
5. Gold Plating is the process of electroplating gold onto a metal item.
6. Copper Plating is the process of electroplating copper onto a metal item.

Electroplating Advantages

The advantages of Electroplating are :

• Electroplating often reduce the friction of the metal surface
• Electroplating protects the original metal by creating a barrier layer
• Due to electroplating, adhesive properties of metal increases
• Electroplating also adds to the thickness of the overall metal

Electroplating Uses

Some applications of Electroplating are :

1. To prevent rusting, metals are frequently coated with other metals.
2. Chromium plating is used on bath taps, automobile bumpers, and other similar items to give them a bright, appealing appearance while also resisting scratches and wear.
3. Silver plating is used for flatware and jewellery.
4. Tin cans are created by electroplating tin onto iron and are used to store food. Tin is a less reactive metal than iron. As a result, food does not come into touch with iron and is therefore protected against spoilage.
   

Related :

• Electrochemical Cells
• Electrolytic Cells
• Redox Reactions

FAQs on Electroplating

What is Electroplating?

Electroplating is the hydrolysis-based plating of one metal onto another, most typically for ornamental purposes or to prevent metal corrosion. Copper plating, silver plating, and chromium plating are examples of specific forms of electroplating.

What are the Applications of Electroplating?

Applications of Electroplating are:

1. Prevention of Rust
2. Chromium Plating of various objects such as bath taps, automobile bumpers, and others.
3. Silver Plating of Flatware and Jewelry.
4. Tin cans are created by electroplating Tin onto Iron.

What is Chromium Plating?

The chromium plating process is an electroplating method for depositing a thin layer of chromium onto a substrate (metal or alloy). 

Chromium Electroplating is accomplished by sending an eectric current between two electrodes immersed in a chromic acid electrolyte bath. The substrate to be coated will be cathode. Chromium atoms are deposited in a layer on the electrode to be plated during the flow of electricity between the two electrodes.

Which of Chromium’s Properties makes it suitable for Electroplating?

Chromium is a corrosive-resistant metal, but other metals, such as steel, corrode readily when exposed to damp air.

What are the Advantages of Electroplating?

The following are some of the benefits of electroplating :

1. Corrosion resistance: a corrosion-prone substance, such as iron, can be protected by a coating of non-corrosive material.
2. Decorative items: otherwise dull surfaces can be given a gleam and sheen. This can be used as a decorative piece.
3. Less expensive decorations: instead of utilizing gold or silver, ornaments can be made out of less expensive metals and then electroplated with gold. This significantly lowers the cost of ornaments.
4. Improving mechanical properties: Electroplating can also help metals improve their mechanical properties.

What are the Disadvantages of Electroplating?

The following are some of the disadvatages of electroplating :

1. Non-uniform plating: electroplating may or may not be uniform, resulting in a plated material with a poor appearance.
2. The technique is both expensive and time-consuming.
3. Pollution potential: after usage, the electroplating solution must be disposed of carefully, posing a threat to the environment.

What are the Factors Affecting Electroplating?

Factors affecting electroplating are:

1. surface area of the electrodes,
2. temperature
3. kind of metal and
4. electrolyte utilized, and
5. amplitude of applied current