Coatings for Custom Heat Exchangers and Cold Plates
Plate-Fin Heat Exchanger
with Chem Film
with Black Anodized Finish
and Alodine Coating
Custom Tube-Fin Heat Exchanger
with Black E-Coat
Custom heat exchangers
and cold plates
are often coated for corrosion protection
or for cosmetic purposes. Chemical conversion coating, anodization, e-coating, and painting are four coating options that will help to minimize corrosion and/or result in a more attractive component.
Chem Film or Alodine
One of the most widely used coating options is chemical conversion coating or chromate conversion coating, also known as "Chem Film" or alodine. Conversion coating helps to minimize surface oxidation and is often specified for military as well as commercial heat exchangers and cold plates. It also sometimes serves as a surface preparation for paint.
Another option that can be used to protect aluminum is anodization. Anodizing minimizes corrosion and abrasion by modifying the crystal structure close to the metal surface. It produces a harder part with even greater corrosion protection. However, it is more expensive than chemical conversion coating.
Electrodeposition or E-Coat
A third coating method that provides corrosion protection is called an e-coat, also known as electrodeposition or electrocoating. A DC charge is applied to a metal part immersed in a bath of oppositely charged paint particles. The paint particles are drawn to the metal part and paint is deposited on the part, forming an even, continuous film over the entire surface. Of the four types of coatings described here, it is the most expensive type of corrosion protection.
Heat exchangers and cold plates may also be painted for corrosion protection or cosmetic purposes. For example, copper heat exchangers are sometimes painted for aesthetics since uncoated copper may change color over time.
Although these are four of the most common coatings for heat exchangers and cold plates, there are a large number of coating options available to Original Equipment Manufacturers (OEMs).