ADHESIVES, GLUES AND SEALANTS


Surface preparation of metals.

The main objective in the preparation of metal surfaces is to improve the wetting properties and adhesion of the metal surface before to apply the adhesive.

On the surface of a metal we find the following layers:

The contaminant layer is a thin layer of dust or chemicals agents adsorbed onto the surface of the metal, to the elimination of that kind of contaminants cleaning agents are used.

metal surface

All metals react with oxygen in the atmosphere, resulting in an oxide layer. Depending on the material of the metal, this oxide layer it can provide an active or passive surface and it may need one treatment or another to ensure a good adhesion of the adhesive on the surface of the metal.

For example, the steel forms different oxide layers depending on its level of alloy with other metals:

If you need to remove the metal oxide layer before to apply the adhesive, you can use the following techniques or processes such as surfaces pretreatment:

Mechanical processes:

Chemical Processes:

Coating processes:

The choice of surface pretreatment to use is determined by:

After making the correct pre-treatment on the metal surface, this surface produces active sites that react with the environment becoming an inactive surface, to avoid such effects activators and primers are used before adhesive application.

Generally the adhesive manufacturer indicated in the technical data sheet recommended surface preparation products or methods for every type of metal that can bond the adhesive.


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