Self-healing coatings as a way extend life of metallic materials
Self -healings coatings as a way extend life of metallic materials
By Mikhail Zheludkevich, Ciceco, Department of Ceramics and Glass Enginnering, Uviversity of Aveiro, Portugal
One major concern of archaeologists and conservators is to limit the alteration and the corrosion of metallic objects which present an important part of human heritage.
It is well known that most of the metals are thermodynamically prone to oxidation processes in presence of different corrosive species.
There is no possibility to change the thermodynamics and completely stop the degradation of metallic objects.
However these processes can be decelerated by reducing rates of corrosion.
Organic coatings are one of the most important ways of protecting metal against corrosive agents, thanks to their diffusion barrier properties.
However defects normally appear in protective coatings during exploitation because of mechanical impact, abrasion, UV-radiation and thermal stresses. After the defects appear the barrier properties of polymer coatings are locally destroyed.
Therefore additional active protection mechanisms are needed in order to prolong life of the coated materials.
The present work reviews main approaches used for creation of self-healing protective coatings for metallic materials.
Most of these technologies can also be applied for preservation of metallic heritage as well.
The main accent of the paper is focused on transparent self-healing polymer coatings.
Different mechanisms of self-healing are addressed including suppression of the corrosion processes by coatings with nanocontainers of corrosion inhibitors as well as strategies based on self-healing polymers.