State that metal objects are electroplated to improve their appearance and resistance to corrosion

Resources | Subject Notes | Chemistry

Electrolysis - Electroplating

Electrolysis - Electroplating

Objective

State that metal objects are electroplated to improve their appearance and resistance to corrosion.

Electroplating Explained

Electroplating is a process where a thin layer of a metal is deposited onto the surface of another metal object. This is achieved using electrolysis.

Why is Electroplating Done?

Electroplating serves several important purposes:

  • Improved Appearance: It can make an object more aesthetically pleasing by giving it a shiny or colored finish.
  • Increased Corrosion Resistance: Coating a metal with a more corrosion-resistant metal (like chromium or nickel) protects the underlying metal from rusting or other forms of degradation.
  • Enhanced Durability: The plating can increase the wear resistance of an object.
  • Improved Conductivity: In some cases, electroplating can improve the electrical conductivity of a metal.

The Electroplating Process

  1. Electrolyte Preparation: The object to be plated is made the cathode (negative electrode) in an electrolytic cell. The anode (positive electrode) is made of the metal that will be deposited. The electrolyte is a solution containing ions of the metal to be plated.
  2. Electrolytic Cell Setup: The cathode and anode are immersed in the electrolyte, and the cell is connected to a DC power supply.
  3. Electrolysis: When the power supply is turned on, the metal ions in the electrolyte are attracted to the cathode and gain electrons, becoming metal atoms that deposit onto the cathode surface. The anode metal loses electrons and dissolves into the electrolyte as ions.
  4. Deposition: A thin, uniform layer of the plating metal is deposited onto the cathode.

Example: Chrome Plating

A common example is chrome plating, where a thin layer of chromium is deposited onto a steel object. This improves the steel's resistance to rust and gives it a bright, shiny finish.

Table: Benefits of Electroplating

Benefit Explanation
Improved Appearance Provides a shiny or colored surface.
Corrosion Resistance Protects the underlying metal from rusting or degradation.
Enhanced Durability Increases the wear resistance of the object.
Improved Conductivity Can enhance the electrical conductivity of the metal.