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Corrosive Environments

Corrosion is the destruction of refined metals and alloys by the environment. It is a completely natural process and can take as little as weeks or in some instances many years. Corrosion can take many forms from general corrosion to a more localised type for example galvanic corrosion and formicary corrosion. The type of corrosion depends on the environment and the materials i.e. metals used.

The most common type of corrosion in the HVAC industry is galvanic corrosion and general corrosion. Corrosion that attacks copper and has become a more significant problem is called formicary corrosion.

This is an extremely localised type of corrosion that will lead to small holes in the copper tubes and ultimate loss of refrigerant gas or chilled water. Pitting is considered a much larger problem than general corrosion because it can go unnoticed until it is too late. A small hole in the copper tube can lead to the failure of the entire HVAC or Refrigeration coil.

General Corrosion

This type of corrosion takes place across the entire surface of the metal surface. Unprotected surfaces with react with contaminants in the environment. The more contaminants in the environment the faster this type of corrosion can damage and jeopardise the efficiency and life of the HVAC and Refrigeration equipment.

The most common type of corrosion in the HVAC industry is galvanic corrosion and general corrosion. Corrosion that attacks copper and has become a more significant problem is called formicary corrosion.

Pitting Corrosion

This is an extremely localised type of corrosion that will lead to small holes in the copper tubes and ultimate loss of refrigerant gas or chilled water. Pitting is considered a much larger problem than general corrosion because it can go unnoticed until it is too late. A small hole in the copper tube can lead to the failure of the entire HVAC or Refrigeration coil.

Formicary Corrosion

This is a form of corrosion in copper tubes of HVAC and Refrigeration coils. It is cause by the presence of organic acids from the environment or manufacturing process. The danger with this type of corrosion it is hard to identify before it’s too late.

Galvanic Corrosion

Galvanic corrosion is the most common form of corrosion in aluminium / copper coils. Galvanic corrosion relies on dissimilar metals being in contact with each other in an electrolyte. This environment is very common in air conditioning units. The corrosion starts where the aluminium fin collars and copper tubes are in contact. The aluminium will corrode because of the huge potential difference between the two metals. As the corrosion of the aluminium fin continues, the fins thermal conductivity is destroyed. Aluminium oxide deposits are formed on the fin surface and have a thermal conductivity less than 10% that of aluminium metal.

THERMAL-XR is building a network of quality distributors and local applicators around the world to service the residential and commercial HVAC and Refrigeration Market.

Thermal-XR
Unit 2/481-483 Victoria Street
Wetherill Park, 2164 NSW Australia
info@thermal-xr.com
+61 2 9756  1781