Corrosion and Inhibitor
Corrosion; It restores processed metals such as steel, copper, zinc to their natural oxidized state as a chemical compound. Inhibitors It is used to prevent oxidation.
What are the Factors Affecting Corrosion? Why is the use of inhibitors necessary?
- Water Chemistry
- Dissolved Gases
- Halogens and Other Oxidants
- Flow Rate
- System or Spatial Configuration Factors
What are the Corrosion Types?
- Uniform Corrosion
- Pitting Corrosion
- Regional Corrosion (Localized Corrosion)
What are corrosion inhibitors?
Corrosion inhibitors are substances that, when added to a medium in a small concentration, effectively reduce the corrosion rate of metal exposed to that environment.
What are the types of corrosion inhibitors?
There are three types of corrosion inhibitors:
- Anodic Inhibitors
- Cathodic Inhibitors
- Mixed Inhibitors
Corrosion inhibition occurs through the use of one or more of three general mechanisms:
- The inhibitor molecule is adsorbed on the metal surface as a result of the chemisorption process, forming a thin protective film by itself or together with the metallic ions.
- The inhibitor allows the metal to form its own protective metal oxide film, thereby increasing its resistance.
- The inhibitor reacts with potentially corrosive substances in water.
When choosing an anti-corrosion agent for its application, several parameters need to be considered, such as:
- Materials to be protected
- Method of application (dipping, spraying, brush, etc.)
- Type of protection required (under process, in storage or transport)
- Type and thickness of coating deposit desired
- Storage, packaging and/or shipping conditions (temperature, humidity)
- Interaction with subsequent processes, if not removed
- Environmental, health and safety requirements
- Product type (oil/solvent or water-based)
Evaluation of the anti-corrosion effectiveness is made by placing a small sample piece (corrosion coupon) of the material to be protected into the environment. The corrosion coupon, which is monitored at regular intervals, gives the most reliable information about whether corrosion has occurred in the entire environment.
In addition, electrochemical methods are also used to evaluate the corrosion prevention effectiveness. The advantages of electrochemical methods are the short measurement times and mechanistic knowledge that aids in the design of corrosion protection strategies and new inhibitors.