**Preface to "Advances in Organic Corrosion Inhibitors and Protective Coatings"**

Metallic components consisting of magnesium, aluminum, steel, and their alloys are widely used in a plethora of applications because of their exceptional mechanical properties and their overall durability. However, they are often damaged by mechanical or chemical processes. Mechanical damage that is caused by the impact of solid particles is called erosion, while electrochemical damage that results from chemical degradation is termed corrosion. The corrosion phenomena, to which every metallic substrate is subjected to, eventually result in the degradation of the metal and the deterioration of its properties. The interaction of a metal with its environment that results to its chemical alteration is called metallic corrosion. According to the literature, corrosion is classified into two types: uniform and localized corrosion. The intervention of either in the alloy environment or in the alloy structure can influence the corrosion protection of metallic materials. Furthermore, interference in the metal alloy environment can be conducted with the utilization of cathodic or anodic protection via the corresponding inhibitors. Therefore, the most common categorization is cathodic, anodic, and mixed-type inhibitors, taking into account which half-reaction they suppress during corrosion phenomena. The majority of the organic inhibitors are of mixed type and perform through chemisorption. The corrosion control of metallic structures is an important task in technical, economic, environmental, and safety terms. Several types of corrosion inhibitors are being employed to prevent metallic dissolution in corrosive media, for which the use of organic inhibitors is one of the most frequent and economic methods. Heteroatoms (O, S, N, and P) and π-electrons in the conjugated form act as excellent corrosion inhibitors for metals and alloys in aggressive solutions [1]. These inhibitors can be incorporated into corrosion-protective coatings. Coatings considered for corrosion inhibition must offer an effective physical barrier, impeding the access of violent materials to the metal surface. In order to update the field of corrosion protection of metal and metal alloys with the use of organic inhibitors, a Special Issue entitled "Advances in Organic Corrosion Inhibitors and Protective Coatings" is introduced. This book gathers and reviews a collection of ten contributions (nine articles and one review), from authors from Europe, Asia, and Africa, that were accepted for publication in this Special Issue of *Applied Sciences*.

> **Ioannis Kartsonakis** *Editor*
