Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers



Reviewed by Raghvendra GopalCheckmark
Last updated: March 8, 2022

What Does Vaporization Mean?

Vaporization is the transition of matter from a solid or liquid phase into a gaseous (vapor) phase. There are two types of vaporization:

  1. Evaporation.
  2. Boiling.

In the context of corrosion protection, vaporization is mainly used to apply coatings to metal.

The delicate nature of the atmospheric corrosion process, which occurs in thin films of electrolyte, causes corrosion inhibitor's transport mechanism. The transport mechanism must diffuse through the electrolyte film to be effective—and then cover the substantial area of the intended surface.

Corrosion-inhibiting mechanisms' precise parameters are not certain. Although, it is believed there are certain essential physical and chemical properties of the benevolent molecules.

There have been various studies on the relationship between vapor pressure and its effectiveness in the volatile corrosion inhibitor (VCI) compound. These studies have emphasized the significance of acceptable values of vapor pressure to achieve vaporization—to alter the kinetics of the corrosion processes. The VCI concept conditions an environment with trace amounts of the inhibitive material to achieve the needed protective effect.


Corrosionpedia Explains Vaporization

There are two widely known and commonly used evaporation technologies:

  1. E-beam Evaporation. In this method, an electron beam is aimed at the source material; this causes local heating and evaporation.
  2. Resistive Evaporation. In this method, the source material is placed in a tungsten boat, which is then heated electrically with a high current to cause evaporation.

Many materials are restrictive in terms of which evaporation method can be used. This typically depends on the material's phase transition properties.

Vaporization uses a strong vacuum environment and is therefore capable of producing very high purity thin films. Moreover, the deposition rate is high, reducing damage to the substrate during deposition. This method is simple and inexpensive.

Although modern methods of vaporization eliminates dual-phase sampling and supports applications using various methods, equipment should still be sturdy enough to mitigate corrosion from sour gas samples that may be high in sulfurs.

Volatile Corrosion Inhibitors

Volatile corrosion inhibitors (VCIs) are chemical compounds released into a confined space which could react with the underside of a tank through the sand pad material, by a diffusion method, to achieve the targeted metal surface. The compounds present are then absorbed into the metal surface, forming a bond that promotes a passive oxide layer on the metal—thereby preventing contaminant molecules from reaching the surface.

VCIs are secondary electrolyte chemical compound layer inhibitors, possess saturated vapor pressure and, under atmospheric conditions, allow for the substance in use to be transported in vapor phase. VCIs are also used alongside cathodic protection (CP) systems.

The customary method to enable the accurate sampling of fossil fuel integrates system components constructed so as to render the equipment surface inert. However, recent technological advances within the material provide superior alternatives.





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