The key difference between electroplating and galvanisation is that electroplating process can be used to apply any suitable metal on an object whereas galvanisation is used to apply a thin zinc layer on a steel.
Electroplating is a type of galvanisation. Electroplating can be used for the application of different metals on surfaces such as gold, silver, chromium, rhodium, copper, etc. However, galvanisation mainly focuses on the application of molten zinc on a metal surface such as steel.
CONTENTS
1. Overview and Key Difference
2. What is Electroplating
3. What is Galvanisation
4. Side by Side Comparison – Electroplating vs Galvanisation in Tabular Form
5. Summary
What is Electroplating?
Electroplating is an analytical process in which one metal is coated on another metal using electrical energy. This process involves an electrochemical cell containing two electrodes that are immersed in the same electrolyte. However, we need to use the object as the cathode. The anode is either the metal that we are going to apply on the cathode or an inert electrode.
In the process of electroplating, the system is first given an electrical current from the outside, which makes the electrons in the electrolyte to pass from anode to cathode. The cathode has removable electrons. In the electrolytic solution, there are metal ions that can receive electrons. Thereafter, these metal ions undergo reduction and become metal atoms. Then these metal atoms can deposit on the surface of the cathode. And, this whole process is called “plating”.
Figure 01: Electroplating
However, we need to carefully choose the electrolyte. If the electrolyte contains other metal ions that can deposit along with the desired metal ion, the plating will be inaccurate. Therefore, the cathode on to which the metal is plated should be clean and free of contaminants. Otherwise, the plating becomes uneven. The major uses of the electroplating process are for decorative purposes or to prevent corrosion.
What is Galvanisation?
Galvanisation is an analytical technique we use to make a thin zinc layer on a substrate. Usually, steel products are used as substrates, and we can perform the galvanisation via submerging the product in a molten zinc bath. During this process, zinc metal is applied on steel to act as a sacrificial anode to protect the steel from rusting. In other words, if there is a scratch on the zinc layer, the steel is still protected. Usually, we call this method “hot-dip galvanisation” because it uses a molten zinc bath at a high temperature, and the product is dipped in it to get a metal layer applied on the surface of the steel.
Figure 02: Galvanised Nails
We can find various types of galvanisation processes depending on the technique. Some of them include the followings:
- Hot-dip galvanisation – it includes the immersion of the substrate in molten zinc
- Continuous galvanising – this is a form of hot-dip galvanisation, but this forms a very thin zinc layer; thus, the corrosion resistance is comparatively less
- Thermal spray – this method includes the spraying of semi-molten zinc on to the substrate
- Electroplating– a common method that uses the item and zinc metal as electrodes in an electrochemical cell
- Mechanical plating – this is an electro-less method that is important in depositing the coat using mechanical energy and heat
What is the Difference Between Electroplating and Galvanisation?
Electroplating is a type of galvanisation. The key difference between electroplating and galvanisation is that electroplating process can be used to apply any suitable metal on an object whereas galvanisation is used to apply a thin zinc layer on a steel. Therefore, electroplating can apply any suitable metal such as zinc, copper, rhodium, chromium, gold and silver while galvanisation applies molten zinc metal.
Below infographic summarizes the differences between electroplating and galvanisation.
Summary – Electroplating vs Galvanisation
Electroplating and galvanisation are important for both decorative and functional applications. Electroplating is a type of galvanisation. The key difference between electroplating and galvanisation is that electroplating process can be used to apply any suitable metal on an object whereas galvanisation is used to apply a thin zinc layer on a steel.
Reference:
1. “Catalase.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 27 Dec. 2017, Available here.
Image Courtesy:
1. “Electroplating Cell” (CC BY-SA 3.0) via Commons Wikimedia
2. “NailsCloseup” By Raysonho @ Open Grid Scheduler / Grid Engine – Own work (CC0) via Commons Wikimedia