# Special Issue on \"Advances in Organic Corrosion Inhibitors and Protective Coatings\"
## 2 Corrosion Inhibitors  
Steel has gained an increasing utilization and is widely used for machinery parts, building construction, and pipelines, because of its low price as well as its machinability and weldability. Three articles were published in this Special Issue related to corrosionprotection of steel in the presence of inhibitors. The corrosion resistance of mild steel under the conditions used for industrial applications was investigated by [PERSON] et al. [2]. Their study investigated the application of organic 2-mercaptoethanolhizode (MBT) and inorganic Na\({}_{2}\)HPO\({}_{4}\) as corrosion inhibitors for the protection of API 5L X42 pipeline steel. The electrochemical characterizations proved that both compounds can be considered as corrosion inhibitors of steel and the corrosion protection mechanisms can be assigned to the protective layers created onto the metal surface through chemisorption of the inhibitors, which prevent chloride's penetration. The synergistic effect of the MBT and Na\({}_{2}\)HPO\({}_{4}\), in a molar ratio of 1:1, revealed the effective performance of the additives with corrosion inhibition efficiency above 90%. [PERSON] et al. [3] investigated the use of glycerin-grafted starch as a bio-copolymer working as a corrosion inhibitor for the protection of C-Mn steel, in the presence of HCl, by electrochemical techniques and the weight loss method. The obtained results revealed that inhibition efficiency enhances with increasing bio-copolymer concentration, reaching a maximum of 94%. Moreover, it was concluded that the corrosion inhibition mechanism might be not only a simple physisorption process on the steel surface, but can also be explained in terms of chemisorption of polymer on the steel surface. The corrosion behavior of steel reinforcement incorporated in mortar specimens, in which both the cement and aggregate are partially substituted by ladle furnace slag (LFS) in respect of the presence of chloride ions, was investigated in the work of the [PERSON] et al. [4]. Electrochemical techniques were used to estimate the corrosion rate as well as the symptoms created in steel rebars in the presence of LFS. Considering the obtained results, it was concluded that in mortars with the presence of mixed-in chlorides, the embodiment of LFS in the mortar at the time of kneading does not negatively influence the corrosive process of the steel rebar. In recent years, studies on copper alloy corrosion have gained much attention in the industrial sector due to the fact that copper and its alloys create several industrially important materials. Many important properties ranged from good thermal properties, formability, electrical conductivities and visual appearance to good corrosion resistance influenced by the alloying elements of copper. Two articles based on copper alloy corrosion protection were published in this Special Issue. In the work of [PERSON] et al. [5], the corrosion inhibition efficiency of 3-mercaptoethanolkyl derivatives of 5-amino-1H-1,2,4-triazole for the a-brass (copper > 65 wt.% and zinc < 35 wt.%) in a chloride media was investigated using electrochemical techniques. Taking into account the obtained result, it was estimated that the degree of protection achieved for all inhibitors can reach a maximum of over 99%. Moreover, it was proven that the protective effect enhances with the length of the alkyl chain. The corrosion protective mechanism is based on the formation of a protective film on the a-brass surface that contains oxides as well as complex compounds of copper and zinc with the inhibitor molecules. In the work of [PERSON] et al. [6], the protection role of cysteine for the copper-based alloys Cu-5 Zn-5 Al-1 Sn, containing zinc (5 wt.%), aluminum (5 wt.%) and tin (1 wt.%) corrosion in sodium chloride solutions, was studied. The electrochemical results proved that the inhibition efficiency improved with increasing cysteine concentration.