What is Electroplating?
You may already know that electroplating is a common metal finishing/improving process that is used in several industrial applications. But you might not be familiar with how electroplating works. Electroplating is nothing new — the earliest incarnations of what would become the modern electroplating process occurred in the early 19th century. As industrial and manufacturing practices have advanced over the past two centuries, the electroplating process has also evolved. Electroplating is known as electrodeposition because the process involves depositing a thin layer of metal onto the surface of a work piece, which is referred to as the substrate. An electric current is used to cause the desired reaction.
Here’s a simplified explanation of how electroplating works: Let’s suppose that a layer of gold is to be electrodeposited onto metal jewellery to improve the appearance of the piece. The plating metal, or coating, (gold) is connected to the anode (positively charged electrode) of the electrical circuit, while the jewellery piece is placed at the cathode (negatively charged electrode). Both are immersed in a specially developed electrolytic solution (bath).
At this point, a DC current is supplied to the anode, which oxidizes the metal atoms in the gold and dissolves them into the bath. The dissolved gold ions are reduced at the cathode and deposited (plated) onto the jewelry piece. Factors that impact the final plating result include:
the chemical composition and temperature of the bath
the voltage level of the electric current
the distance between the anode and the cathode
the electrical current application’s length of time.
Uses of Electroplating?
In addition to improving the appearance of the substrate, or base material, electroplating is used for multiple other purposes. A primary application is to improve the work piece’s resistance to corrosion. The plated layer will often serve as a sacrificial coating, meaning it will dissolve prior to the base material. Other common uses of electroplating include:
Building the thickness of a metal surface
Increasing wear resistance
Improving electrical conductivity — such as when plating a copper layer onto an electrical component
Preparing surfaces for enhanced adhesion prior to painting or e-coating
Protecting against surface abrasions
Improving surface uniformity
Which Metals Are Used in the Electroplating Process?
Metals commonly used in electroplating include zinc, copper and tin, as well as precious metals such as gold, silver and palladium. Plating can occur with individual metals or in various combinations (alloys) that can provide additional value to the electroplating process. Price, substrate composition and desired result are key factors when determining the most appropriate electroplating process.