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.
In this article, we are going to learn the basic concepts of the electroplating process, its applications, definition, working principle, and types. We will also explore the examples of the electroplating process, factors affecting it, its advantages and uses with diagram.
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 main driving force behind the electroplating is electric current.
Electroplating is usually done for ornamental purposes or for increasing the life of a more important metal by coating it with a less important metal.
For example, you have seen your mother purchasing golden ornaments from the market at a much cheaper price than gold and you wonder why the ornament cost so less. The reason behind it is that those are made up of copper or any other cheaper metal but electroplated with gold hence costing less and appearing shiny.
Electroplating Process – Principle
The working principle of Electroplating is 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.
The process of electroplating is based on the following principle:
Electric current is used to reduce dissolved metal cations, resulting in a thin, coherent metal coating on the electrode, which is also the main
principle of electroplating.
In the electrical oxidation of anions on a solid substrate, such as the production of silver chloride on silver wire to make silver chloride electrodes, electroplating is frequently used.
Electroplating is mostly used to change the surface properties of an object (for example, corrosion resistance, lubricity, and abrasion resistance), but it can also be used to add thickness or create objects by electro-shaping.
Electroplating Process- Principle
The setup of Electroplating involves the following components:
The metal to be used for coating
The metal on which coating is to be done.
It should be the aqueous salt solution of anode metal.
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. Following are some examples of electroplating setup
Electrode Types – Cathode and Anode Definition
An electrode is a solid electric conductor usually metal that conducts electricity through nonmetallic materials, liquids, gases, plasmas, and vacuums.
Electrodes are the sites where oxidation and reduction occur.
The definition of cathode and anode is given below:
Anode is positively charged electrode. It is the site from which electron leaves and enter the electrolytic solution. Due to this, oxidation occurs at anode.
Cathode is negatively charged electrode to which electron enter from the electrolyte. Due to this reduction occur at cathode.
Electrodes are usually good conductors of electricity. They can be of metal or graphite.
Note: The the nature of electrode which will behave as a cathode or anode depends on the function performed by the cell.The direction in which a cell functions determines whether an electrode is a cathode or an anode.
For example, when a cell switches from acting galvanically (that is, producing energy like a battery) to electrolysis (that is, receiving energy), the cathode becomes the anode and vice versa.
Electrolyte Definition
An electrolyte is a substance that transmits electric current by dissociating into positively and negatively charged particles known as ions. These ions which migrate toward the electrodes of opposite nature i.e. cation being a positively charged particle will migrate towards the cathode which is of negative nature while an anion being negative in nature will get attracted towards anode which is positive in nature.
Electrolyte Example
Acids, bases, and salts are the most well-known electrolytes, which ionize when dissolved in water or alcohol. Salts when melted in the absence of any solvent for example such as sodium chloride, behave as electrolytes; some polymers are electrolytes even in the solid state.
Electroplating Process – Working
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 jewelry 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. The 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 about, Chemical Effect of Electric Current
Here are some examples of electroplating :
Use Copper electrodes as an anode and Copper sulfate solution as an electrolyte. On the negative electrode, the metal will be copper electroplated. The addition of copper ions from the positive electrode replenishes the Cu in the solution.
To avoid corrosion or rusting, bathroom taps made of iron or steel are electroplated with chromium metal in which chromium is connected to an anode and chromium salt solution is used as an electrolyte.
Electrolysis is the decomposition of a chemical substance in a solution when an electric current is sent through it. The chemical action of electric current is responsible for this process.
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.
Various types of Electroplating process are,
is the process of electroplating chromium onto a metal item.
is the process of electroplating tin onto a metal item generally iron.
is the process of electroplating nickel onto a metal item.
is the process of electroplating silver onto a metal item.
is the process of electroplating gold onto a metal item.
is the process of electroplating copper onto a metal item.
Electroplating – Advantages
The advantages of Electroplating are mentioned below:
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
Applications of Electroplating are :
To prevent rusting, metals are frequently coated with other metals.
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.
Silver plating is used for flatware and jewelry.
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.
Conclusion
The process of electroplating is an important process in the fields of modern science and industry. This technique, which involves the deposition of a metal layer onto a substrate through the power of electric current, is not just about enhancing the appearance of objects. It plays a crucial role in extending their durability and resistance to corrosion. This article discussed the basic concepts of the electroplating process, its applications, definition, working principle, and types. We also learnt about the examples of the electroplating process, factors affecting it, its advantages and uses with diagram.
Read More,
Electroplating – FAQs
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.
Applications of Electroplating are:
Prevention of Rust
Chromium Plating of various objects such as bath taps, automobile bumpers, and others.
Silver Plating of Flatware and Jewelry.
Tin cans are created by electroplating Tin onto Iron.
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.
Chromium is a corrosive-resistant metal, but other metals, such as steel, corrode readily when exposed to damp air.
The following are some of the benefits of electroplating :
- Corrosion resistance:
a corrosion-prone substance, such as iron, can be protected by a coating of non-corrosive material.
- Decorative items:
otherwise dull surfaces can be given a gleam and sheen. This can be used as a decorative piece.
- 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.
- Improving mechanical properties:
Electroplating can also help metals improve their mechanical properties.
The following are some of the disadvatages of electroplating :
- Non-uniform plating:
electroplating may or may not be uniform, resulting in a plated material with a poor appearance.
The technique is both expensive and time-consuming.
- Pollution potential
: after usage, the electroplating solution must be disposed of carefully, posing a threat to the environment.
Factors affecting electroplating are:
surface area of the electrodes,
temperature
kind of metal and
electrolyte utilized, and
amplitude of applied current
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Last Updated :
20 Dec, 2023
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