Bad coating instead of no coating? Wrong choice

by Fleming. Team

Coating-related failures often give companies hard times. Even a failure on a very small part of a surface can lead to corrosion, a weakening of structures and additionally to extensive damages that can burden companies with high reparation costs.

Coating failure is defined by the loss or reduction of coating bond strength between coats and the substrate. It can happen due to the expiration of a coating's lifetime, but also unexpectedly and rapidly. Usually the initiation process is slow, but when it starts, it spreads quickly. Statistics show that the most common cause for a coating's failure is because of bad surface preparation and application. For example, improper or insufficient disinfection and rust; mildew removal; or abrasive or other contamination of surface will lead to flawed adhesion of coating to a metal surface. One of the problems is that although the surface might look undamaged, the major corrosion defects occur on the substrate beneath.

Let’s have a look at several coating failures and what to do to prevent them.

Chalking – Occurs because of powdery material on the surface. Coating with higher UV resistance can avoid chalking.

Orange peeling – Uneven flaws (hills or holes) on the coating surface which look like orange skin. Can be eliminated by changing coating conditions. Once formed, it can be cured by sanding and application of another layer of coating.

Erosion – Elimination of coating due to contact with an environmental element. To prevent erosion, materials with higher hardness are needed.

Reparation of a damaged surface can be very long and expensive process in which companies can suffer huge loses. These repair costs can be much higher than those associated with the initial coating. Proper coating application, appropriate surface preparation and skilled personnel are crucial from the very beginning. Don't underestimate prevention; it will cost you much less in the end.




For more information, search: https://www.corrosionpedia.com/2/1405/prevention/c...

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