Corrosion Inhibitor
Chemical substances used to protect or slow the metal surface corrosion are called corrosion inhibitors. In other cases these chemicals work by coating the metal surface or by blocking the reactions leading to corrosion. The process whereby metal is deteriorated by chemical or electrochemical reactions with its environment is called corrosion, and it is a major problem in industrial equipment, pipelines, automobiles, and numerous metal structures. These structures need corrosion inhibitors to extend their lifespan and remain performing.
What are Corrosion Inhibitor?
Corrosion inhibitors can be classified in several ways dependent on the type of metal and the environment in which they are used. Here are the main types of corrosion inhibitors:
- Anodic Inhibitors: By slowing down the corrosion process these inhibitors deal with the anodic area of the metal. Usually they form a protective film on oxidizable metal surfaces. Anodic inhibitors are used widely, the most common anodic inhibitors being chromates, molybdates and phosphates.
- Cathodic Inhibitors: Cathodic inhibitors decrease the corrosion current by acting in the cathodic areas of corrosion cells. According to this, these inhibitors work by inhibiting the forming of hydrogen gas on the metal surface. Cathodic inhibitors are mainly zinc, calcium and magnesium salts.
- Mixed Inhibitors: In both anodic and cathodic areas, these inhibitors are effective. A general protective film develops on surface of the metal which prevents corrosion. This includes carboxylates and organic amines.
- Oxygen Inhibitors: Most of the time, the presence of oxygen speeds corrosion. Corrosion is inhibited by oxygen inhibitors by chemically binding the dissolved oxygen in water. Oxygen inhibitors that are commonly used are sodium sulfite and hydrazine.
- Filming Inhibitors: The purpose of these inhibitors is to provide a thin film layer of the inhibitor, preventing direct contact between the metal and its environment. It slows down or stops the corrosion process. Filming inhibitors are widely used organophosphorus compounds and organic amines.
What is Corrosion Preventatives?
There are all types and methods used in corrosion prevention for metal structure and equipment. They can be used with or without corrosion inhibitors. Here are the main corrosion preventative methods and materials:
- Coatings: A common method to prevent corrosion is to cover metal surface with protective coatings. The corrosion is interrupted by these coatings – they prevent contact between the metal and its environment. Metal surfaces are protected often with paints, varnishes, epoxy coatings, and powder coatings.
- Galvanization: The process of coating steel and iron surface with zinc is known as galvanization. But, zinc protects iron and steel surfaces before the onset of corrosion. Metal structures used outdoors and in harsh environmental conditions are protected from galvanization.
- Cathodic Protection: In this method the metal surface becomes a cathode as this prevents corrosion. Cathodic protection is applied using two main methods: impressed current protection and galvanic anode protection. These methods are applicable for large structures such as pipelines, tanks, and marine structures in bulk metal.
- Anodic Protection: Anodic protection slows down the corrosion process, by making the surface act as an anode. It’s used pretty often for protecting stainless steel and other alloys.
- Combined Use with Corrosion Inhibitors: When combined with chemical corrosion inhibitors, the physical methods mentioned above provide greater effectiveness in terms of physical protection. For instance, multifaceted protection results from painting a metal surface at the same time as adding inhibitors.
- Material Selection: Preventing corrosion, the first step, is to select corrosion resistant materials. In critical applications corrosion resistant material such as stainless steel, titanium, alloyed metals are used.
- Environmental Control: In order to slow the corrosion process, however, controlling environmental conditions is important. Such methods as controlling humidity or reducing oxygen or removing corrosive substances of environment.
Extending the life of metal structures and equipment relies on corrosion inhibitors and corrosion preventative methods. Corrosion has two effects it weakens metal surfaces and structural integrity loss and presents increased safety risks. Consequently, corrosion control is critical to being able to guarantee that the industrial processes, infrastructures, and equipment operate efficiently and safely.
To protect metal surfaces, direct chemical action is also accomplished through corrosion inhibitors. There are in fact various types of inhibitors, including anodic, cathodic inhibitors, filming inhibitors, and oxygen inhibitors, with the resultant protection generally broad. Corrosion preventative techniques such as coatings, galvanization, cathodic protection, and material selection provide physical and chemical protection to metal surface, simultaneously.
To be successful at corrosion control, you must choose the right inhibitors and ways of prevention. Where these metal surfaces are exposed in specific conditions and to specific corrosion mechanisms, this should be done. Metal structures live longer with proper applications, they are cheaper to maintain, and can operate safely.
