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What is Electroplating?

  • Last Updated : 24 Jun, 2021

Conductors of electricity are materials that allow electric current to easily pass through them. Electrical conductivity is a measurement of a substance’s ability to enable an electric current to flow through it. Solid metals and graphite are good electrical conductors with a high electrical conductivity. Some liquids are good conductors as well. Water that has been purified or distilled is a poor conductor of electricity. However, even a little amount of contaminants (salts and minerals) makes water a good conductor because it includes ions that carry electricity. As a result, water from taps, wells, ponds, rivers, seas, lakes, and other bodies of water carry electricity due to contaminants. Acid, base, and salt solutions make up the majority of electrically conducting liquids. The molecules in a conducting solution disintegrate into ions when electricity is transmitted across them. Ions are positively or negatively charged atoms or groups of atoms. Electrical conduction occurs in the liquid as a result of these ions. Before we look at what electroplating is, it’s a good idea to review some basic concepts of chemical effects of electric current:

Electrolyte

An electrolyte is a substance that transmits electric current by dissociating into positively and negatively charged particles known as ions, which migrate toward and are normally discharged at the negative and positive terminals (cathode and anode) of an electric circuit. Acids, bases, and salts are the most well-known electrolytes, which ionize when dissolved in water or alcohol. When melted in the absence of any solvent, many salts, such as sodium chloride, behave as electrolytes; and some, such as silver iodide, are electrolytes even in the solid state.

Electrodes

An electrode is a solid electric conductor that conducts electricity through nonmetallic materials, liquids, gases, plasmas, and vacuums. Electrodes are usually good conductors of electricity, but they don’t have to be made of metal.

Cathode and Anode

At the electrodes of an electrochemical cell, reduction and oxidation reactions occur. The cathode is the electrode where the reduction takes place. The anode is where oxidation takes place.

The direction in which a cell functions determines whether an electrode is a cathode or an anode.

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.

Electrolysis

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.

Two electrodes are put into the solution and connected to the battery terminals via a switch. An electrolytic cell is the name for this configuration. The anode is the electrode that is connected to the positive terminal of the battery, while the cathode is the electrode that is attached to the negative terminal.

In order to refine and extract metals from impure samples, electrolysis is utilized. This is referred to as electrorefining. It can also be used to cover one metal with another metal.

Chemical Effect of Electric Current

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

  • The formation of gas bubbles on the electrodes
  • Metal deposition on electrodes
  • Color changes in solutions

Electroplating

Plating a metal onto another by hydrolysis, usually to avoid metal corrosion or for ornamental purposes. An 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 thick

or create objects by electro shaping.

This is how we can construct electroplate. Electroplating is done with a brine 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.

Example:

  1. Use Copper electrodes and Copper sulphate solution as electrolyte On the negative electrode, copper is electroplated. The addition of copper ions from the positive electrode replenishes the Cu in the solution.
  2. To avoid corrosion or rusting, bathroom taps made of iron or steel are electroplated with chromium metal.

Electroplating of key.

Types of electrolysis:

  • Chromium plating is the process of electroplating chromium onto a metal item.
  • Tin plating is the process of electroplating tin onto a metal item.
  • Nickel plating is the process of electroplating nickel onto a metal item.
  • Silver plating is the process of electroplating silver onto a metal item.
  • Gold plating is the process of electroplating gold onto a metal item.
  • Copper plating is the process of electroplating copper onto a metal item.

Working of Electroplating

 let’s take an example of a gold coating. In this instance, a layer of gold is to be electrodeposited on metallic jewellery to enhance its appearance. 

Usually, the gold plating is connected to the anode (positive charged electrode) of the circuit and the jewellery is kept at the cathode (negative charged electrode). Both are kept immersed in a highly developed electrolytic bat (solution). At this stage, a DC current is supplied to the anode that oxidizes the gold atoms and dissolves them into the solution.

The dissolved ions of gold are reduced at the cathode and plated on the jewellery.

Factors affecting Electroplating

The plating is influenced by a number of significant elements. These are some of them:

  • The current voltage level.
  • The bath’s temperature and chemical makeup.
  • The amount of time that has passed since the last update.
  • The distance between the cathode and the anode is the distance between the cathode and the anode.

Applications of Electroplating

  1. To prevent rusting, rusted 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 to flatware and jewelry.
  4. Tin cans are created by electroplating tin onto iron and used to store food. Tin is a more reactive metal than iron. As a result, food does not come into touch with iron and is therefore protected against spoilage.

Sample Problems

Ques 1. What exactly is the point of electroplating?

Answer:

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. Manufacturers can use low-cost me

like steel or zinc to electroplating.

Ques 2. Write few applications of electroplating.

Answer:

Applications of electrolysis are:

  1. To prevent rusting, rusted 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 to flatware and jewelry.
  4. Tin cans are created by electroplating tin onto iron and used to store food. Tin is a more reactive metal than iron. As a result, food does not come into touch with iron and is therefore protected against spoilage.

Ques 3. What is chromium plating and how does it work? Which of chromium’s properties makes it suitable for electroplating?

Answer:

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

Electroplating is accomplished by sending an electric current between two electrodes immersed in a chromic acid electrolyte bath. The substrate to be coated will be one of the electrodes. 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.

Ques 4. What are the advantages of electroplating

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Answer:

The following are some of the benefits of this method:

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.

Ques 5. What are the disadvantages of electroplating?

Answer:

The following are some of the cons of this method.

  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.

Ques 6. What factors have an impact on electroplating?

Answer:

A number of things have an impact on this procedure. Surface area of the electrodes, temperature, kind of metal and electrolyte utilized, and amplitude of applied current are only a few of these variables.


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