Control of Corrosion by Modifying the Environment

By
On:

In many cases corrosion can be effectively controlled by changing or modifying the corrosive environment by:

The corrosion nature is reduced by modifying the environment:

  1. the removal of harmful constituents in the environment and
  2. the addition of specific substances, which neutralise the effect of corrosive constituents of the environment.

1. Deaeration

Presence of more amount of dissolved oxygen enhances corrosion. Deaeration can be followed for removal of dissolved oxygen. This can be done by increasing the temperature or by applying mechanical agitation.

2. Deactivation

Deactivation is a process of removing dissolved oxygen by adding some chemicals in aqueous solution, as listed below.

  • Addition of sodium sulphite.
  • Addition of hydrazine.

3. Dehumidification

By lowering the relative humidity of air, the moisture in the air can be reduced. This can be done by adding silica gel (or) alumina which can absorb the moisture from the corroding surface.

This is used only in a closed area like air-conditioned shop.

4. Alkaline neutralisation

The acidic character of the corrosive environment due to the presence of H2 S, HCl, CO2, SO2 etc. can be neutralised by spraying alkaline neutralisers like NH3, NaOH, lime etc.

This method is used to control corrosion in refinery equipment.

5. Corrosion inhibitors

An inhibitor is a substance when added to a corrosive environment in small quantities, decreases the corrosion rate. Chemical reagents which are effective in reducing anodic reaction are called anodic inhibitors and those which reduce cathodic reaction are called cathodic inhibitors.

Read More Topis
Types of electrochemical corrosion
Factors influencing the corrosion
Definition and origin of electrode potential

Santhakumar Raja

Hello The goal of this blog is to keep students informed about developments in the field of education. encourages pupils to improve as writers and readers.

For Feedback - techactive6@gmail.com

Leave a Comment