4.4 Electroplating (Deposition Using the Same Electrode)

Introduction

Electroplating is an important industrial application of electrolysis. It is used to coat one metal with another metal to improve appearance, protect against corrosion, or provide special surface properties.

The electrolytic process used to deposit one metal on another metal is called electroplating.

This section explains what electroplating is, how it works, and its important applications.

Definition

Electroplating: The electrolytic process used to deposit one metal on another metal is called electroplating.

In simple words: Electroplating is the process of coating one metal with a thin layer of another metal using electricity.

Main Idea

• An object can be electroplated by making it the cathode in an electrolytic tank containing ions of the plating metal.
• The plating metal is made the anode.
• On passing electricity through the electrolytic tank, a thin layer of anode metal is deposited on the surface of the object.
• The electrolyte contains ions of the plating metal.

Core Concept

Key rule: The metal to be plated onto the object comes from the anode. The object being plated is always the cathode.

Detailed Explanation

How Electroplating Works

• The object to be plated is made the cathode in an electrolytic tank.
• The plating metal is made the anode.
• The electrolyte contains ions of the plating metal.
• When electricity is passed through the electrolytic tank:
• A thin layer of the anode metal is deposited on the surface of the object.

Key point: The anode metal dissolves, and the cathode gains a coating of the same metal.