https://orcid.org/0000-0001-7849-9583
Corrosion has a huge economic, environmental, and adverse sustainability impact on virtually all facets of metallic materials, including power facilities, integrated circuits, chemical industries, desalination, bridges, oil and gas pipelines, etc. Annual costs caused by corrosion are estimated in 3 ∼ 5% of the global gross domestic product (GDP) for industrialized countries in the World. Most of all, the disposal and further substitution of the damaged elements involves an additional consumption of energy and resources. The subject of corrosion protection has been a conventional research topic in the past few decades, but more advanced knowledge is still required to win the battle. A comprehensive understanding of this phenomenon will guarantee an improved design to reduce the dramatic consequences. The objective of the special issue is to report on the advances in experimental, theoretical, and computational aspects including (i) Organic and plant extract corrosion inhibitors; (ii) Metal coating formulations and techniques; (iii) In situ real-time monitoring of corrosion.
The special issue includes 12 papers focusing on the study of corrosion and protective behavior of metals, which specifically reveals the corrosion inhibition behavior of organic compounds and plant extracts in different acidic media, the influence of inhibitor molecular structure-activity structure on corrosion inhibition performance, the prediction of efficient corrosion inhibitor structure combined with quantum chemical calculations, advanced laser cladding coating techniques and automatic detection of corrosion inhibition effects in situ by image texture analysis of corroded metal surfaces.
The special issue includes contributions from highly reputed experts from different countries, including India (Prof. D. S. Bhuvaneshwari – Thiagarajar College, Madurai; Prof. Menaka Ramanathan – Arts and Science College;, Prof. Dakeshwar Kumar Verma – Government Digvijay Autonomous Postgraduate College; Prof. Mohammad Mobin – Faculty of Engineering and Technology; Prof. Priyabrata Banerjee – CSIR-Central Mechanical Engineering Research Institute); Turkey (Prof. Murat Farsak – Osmaniye Korkut Ata University); Nigeria (Prof. Temitope O. Olomola – Obafemi Awolowo University); China (Prof. Wilfred Emori – University of Science and Engineering; Prof. Yue Zhang, Ocean University of China); Singapore (Prof. Hongfei Liu – Institute of Materials Research and Engineering); and Saudi Arabia (Prof. Aisha H. Al-Moubaraki – University of Jeddah).
Ganesan et al. reported the successful synthesis of aminoantipyrinoanthracenyl imine (AAPAI) compound using a simple microwave method. The corrosion inhibition behavior of AAPAI on mild steel in H2SO4 medium was investigated by weight loss, surface morphology, and electrochemical test. The results proved that AAPAI can prevent the corrosion of mild steel due to the formation of a preventive film with a maximum efficiency of 86.4%. The kinetics and thermodynamics of the reaction of AAPAI on the mild steel surface confirmed that this reaction is spontaneous and combination of physical and chemical adsorption processes. Ramanathan et al. have selected natural polymer chitosan and vanillin to synthesize porous Chitosan vanillin Schiff base (ChVSB) containing the imine structure and investigated its corrosion inhibition behavior. ChVSB is a mixed-type inhibitor showing monolayer chemisorption, and the hydroxyl and imine groups in ChVSB can chelate with calcium ions of calcium carbonate. Farsak et al. reported the preparation and characterization of a new benzimidazolium salt which corrosion inhibition efficiency on mild steel up to 97.2%. Theoretical calculations confirmed that the adsorption of the benzimidazolium salt inhibitor molecules on iron surface was produced in multiple active sites, and the bonds between the N, C atoms in the inhibitor molecule and the metal Fe atom is relatively stable. Dewangan et al. investigated the corrosion inhibition behavior of N-hydroxypyrazine-2-carboxamide (NHP) for mild steel in HCl solution and they reached an inhibition efficiency of 93.51% at 200 ppm and 298 K. Computational chemical analysis confirmed that the hydroxyl and amino groups increased the polarization of NHP molecule, thereby enhancing the adsorption capacity of the inhibitor to metallic iron. Olomola et al. reported the synthesis of two 3-chloromethylcoumarins via Baylis-Hillman reaction, their corrosion protection properties were studied by gravimetric and electrochemical methods. These compounds were good inhibitors of steel corrosion in HCl, particularly for higher concentrations. Overall, designing synthetic corrosion inhibitors have been advocated as a low cost, simple, and effective approach of shielding metal against corrosion under various circumstances.
The plant extracts have been widely developed as corrosion inhibitors because of their excellent properties such as wide sources, low toxicity, and biodegradability. Cheng et al. studied the application of Ganoderma lucidum, a wood-decaying fungus composed of 36 triterpenoids, in the corrosion protection of carbon steel. The corrosion inhibition efficiency of Ganoderma lucidum crude extract was better by more than 10% than that of triterpenoid extract, and the carboxyl oxygen, hydroxyl, and π electrons in triterpenoids have high binding energies to Fe atoms. Al-Moubaraki and co-workers reported that black mustard seeds (BMS) extract had good inhibition performance in H2SO4 medium as corrosion inhibitor, because for a concentration of BMS of 3.5 g/L, the inhibition efficiency was higher than 93%. Molecular dynamic simulations confirmed that the O, S, and N heteroatoms in the Sinigrin molecule in BMS were active sites that can bind to Fe atoms.
Mobin et al. reported the synthesis of AAE-AgNPs nanoparticle composites by combining the natural extract Artemisia absinthium (AAE) with silver nanoparticles (AgNPs), and the structure and properties of the AAE-AgNPs nanoparticle composites were characterized by FTIR, XRD, and dynamic light scattering spectroscopy. The corrosion inhibition behavior and inhibition mechanism of AAE-AgNPs were explained by the formation of a protective film on the surface of mild steel by physical adsorption. The optimum corrosion inhibition efficiency was higher than 90% and the nanomaterials injected into the extract can enhance its stability and durability in the medium. Wen et al. reported organic-inorganic composites polyaniline (PANI) and aluminum tripolyphosphate (ATP) with good corrosion inhibition properties. PANI-ATP combined with waterborne epoxy resin was used as a coating for corrosion protection of 304 stainless steel. The PANI-ATP/EP composite coating maintained good corrosion protection performance for 170 days, indicating that the composite coating has long-term performance. Liu et al. systematically described the recent advances in laser-cladding (LC) of metal alloys for protective coating. The latest research progress on high-speed LC, triple beam LC, magnetic-field assisted LC, ultrasonic vibration assisted LC, and cold-working assisted LC is highlighted in this review. By summarizing researches on current LC methods, the authors predict that in situ data collection and machine learning will be effective in optimizing the parameters of laser cladding and further understanding of the microstructure of coatings.
Banerjee et al. evaluated the anticorrosion properties of three double azomethine functionalised organic molecules using ab initio density functional theory and Monte Carlo simulation approaches. The obtained parameters such as adsorption energy, binding energy, and surface coverage can be reasonable measures of inhibition efficiency. Sarkar et al. investigated the use of image texture analysis to assess the corrosion inhibition efficiency of microscopic images of corroded metal surfaces, thereby shortening the experimental time. This methodology will lay the foundation for automated determination of corrosion inhibition efficiency in the future. Apparently, computer-aided applications in corrosion protection are becoming more and more popular, which can significantly the experimental screening and saving manpower and material resources.
By collecting these papers, we hope to enrich and expand the horizons of JAST readers and researchers in corrosion protection of metallic materials. I would like to express my sincere appreciation to the authors for their patience with the process and the referees for providing insightful comments on these manuscripts. I am also grateful to the Editor-in-Chief of JAST, Prof. José Miguel Martín-Martínez, for giving me the opportunity to elaborate this special issue.