PurposeThe corrosion behaviour of titanium alloy surface when fluid with different flow rates flows through welded joints with different residual heights was explored.Design/methodology/approachThe experiment uses a combination of array electrodes and simulation.FindingsIt is found that when the weld reinforcement exists, the corrosion tendency of both ends of the weld metal is greater than that of other parts of the welded joint due to the influence of high turbulence kinetic energy and shear stress. The presence of weld reinforcement heights makes the fluid behind it fluctuate greatly. The passivation films of both the base metal (BM) at the rear and the heat-affected zone (HAZ) are more prone to corrosion than those of the front BM and HAZ, and the passivation film is rougher.Originality/valueThe combination of test and simulation was used to explore the influence of electrochemical and hydrodynamic factors on the corrosion behaviour of titanium alloy-welded joints when welding residual height existed.

PurposeThis study aims to evaluate the protection performance of zinc as sacrificial anode for ABS A steel in the presence of H2S under different temperatures, pH and salinities.Design/methodology/approachIn this paper, weight loss measurements and electrochemical measurements are used to evaluate the corrosion degree of zinc and ABS A steel.FindingsUnder the conditions involved in this work, it is shown that zinc is a nice sacrificial anode with the reason of its stable potential and excellent anode current efficiency according to the relevant standard. And it is also found that the hydrogen evolution does not occur on ABS A steel specimens. The potential difference between cathode and anode is suitable; thus, it can be concluded that each steel is well protected.Originality/valueTo the best of the authors’ knowledge, no other study has analyzed the protection mechanism and effect of zinc as sacrificial anode in H2S-containing environments under high temperature at present.

PurposeAs a common form of failure in industry, corrosion causes huge economic losses. At present, with the development of computational techniques, artificial intelligence (AI) is playing a more and more important role in the field of scientific research. This paper aims to review the application of AI in corrosion protection research.Design/methodology/approachIn this paper, the role of AI in corrosion protection is systematically described in terms of anticorrosion materials and methods, corrosion image recognition and corrosion life prediction.FindingsWith efficient and in-depth data processing methods, AI can rapidly advance the research process in terms of anticorrosion materials and methods, corrosion image recognition and corrosion life prediction and save on costs.Originality/valueThis paper summarizes the application of AI in corrosion protection research and provides the basis for corrosion engineers to quickly and comprehensively understand the role of AI and improve production processes.

PurposeWhen smelting Al-Li alloy, the material inevitably comes into contact with various oxide-refractories. These refractories are subjected to varying degrees of melt-corrosion at high temperatures. The purpose of this study is to find stable oxide refractories at casting temperature.Design/methodology/approachFour materials were selected for evaluation, and their corrosion by the Al-Li alloy at casting temperature and different holding times was measured. Subsequently, scanning electron microscopy and energy-dispersive spectroscopy were used to study the interfaces. Stable refractory materials were selected by comparing the thicknesses of the reaction layers.FindingsThe thickness of the Al-Li/ZrO2 reaction layer varies linearly with the square root of the holding duration. Therefore, the growth of the reaction layer is controlled by diffusion. The reaction layer of Al-Li/Al2O3 is thinner, and its growth is also controlled by diffusion. However, there were no obvious reaction layers between the Al-Li alloy and MgO or Y2O3. By comparing these reaction-layer thicknesses, the order of stability was found to be ZrO2 < Al2O3 < MgO and Y2O3.Originality/valueThese results provide a scientific basis for the optimal selection of refractory materials for Al-Li alloy smelting.

PurposeThe purpose of this paper is to study the effect of vapor assembly sequence and assembly temperature on the corrosion protection of the complex silane films Al alloy. The performance and application range of silane films are enhanced.Design/methodology/approachThe complex silane films were successfully prepared on the surface of aluminum alloy using via vapor phase assembly of 1,2,3-benzotriazole (BTA) and dodecyltrimethoxysilanes (DTMS). The protection of the assembly films against corrosion of Al alloy is investigated by the electrochemical measurements and the alkaline solution accelerated corrosion test. Thickness and hydrophobicity of the complex films are studied using ellipsometric spectroscopy and contact angle tests.FindingsIt shows that the anti-corrosion ability of the complex films is overall superior to that of the single-component assembled films. DTMS-BTA films have larger thickness and best anti-corrosion ability. The alkyl chains in DTMS have better compatibility with BTA molecules. The rigid BTA molecule can permeate into the long alkyl chain of DTMS as fillers and improve the barrier properties of the complex films.Originality/valueIn this paper, a green and efficient method of vapor phase assembly is proposed to rust prevention during manufacture of Al alloy workpiece.

PurposeThis paper aims to investigate the effect of characteristic parameters of pits on the mechanical properties and fracture model of cable steel wires.Design/methodology/approachThe tensile test and finite element analysis of steel wires with corrosion damage were carried out. The stress development of corroded steel wire under corrosion morphology was studied by the 3D reverse reconstruction technology. The internal relationship between the stress triaxiality, equivalent plastic strain and pit depth, depth-width ratio of corroded steel wire was discussed.FindingsWith the increase of corrosion degree, the neck shrinkage phenomenon of steel wire was not significant, and the crack originated near the pit bottom and expanded to the section inside of specimen. The fiber area of corroded steel wire decreased while the radiation area increased, and the ductile fracture gradually changed to brittle fracture. The pit size significantly changed the triaxial degree and distribution of stress and accelerated the initiation and propagation of internal cracks at the neck shrinkage stage.Originality/valueThe proposed fracture model based on the void growth model could accurately simulate the fracture behavior of steel wires with corrosion damage.

PurposeThe purpose of this paper is to confirm the importance of using metal–organic frameworks (MOFs) in the field of corrosion control due to their potential use as corrosion inhibitors.Design/methodology/approachNH2–MIL–101(Cr), an amine-functionalized chromium-based MOF [Cr(III)-MOF], was prepared by solvothermal technique. Thereafter, Cr-MOF was used as an anticorrosion additive for mild steel (MS) in 1 m HCl solution. This inhibition behavior was tested by electrochemical tests including electrochemical impedance spectroscopy and potentiodynamic polarization (PDP).FindingsIncreasing the added amount of Cr-MOF enhances its inhibition performance, which attained 96.40% at 30 ppm. The obtained data from PDP measurements describe Cr-MOF as a mixed-type inhibitor. Based on SEM/EDS and FTIR analysis, the adsorption of Cr-MOF on the surface of MS that prevents MS corrosion has been demonstrated. Furthermore, Langmuir model is the most adequate adsorption isotherm for the obtained experimental data.Originality/valueThis study revealed that NH2–MIL–101(Cr), an amine-functionalized chromium-based MOF (Cr(III)-MOF), is a potential corrosion inhibitor for MS in 1 m HCl solution.

PurposeThis paper aims to reveal the corrosion mechanism and corrosion development regulation of marine engineering structural steel in the marine environment and provide constructive suggestions for marine immersed tunnel engineering.Design/methodology/approachIn this study, marine engineering structural steel’s behavior and corrosion prediction were carried out under the conditions of no cathodic protection and under-protection by artificially adding dissolved oxygen in a simulated seawater solution as a depolarizing agent.FindingsMarine resources are rich in China. With the development of the economy and the improvement of engineering technology, marine engineering structural steel is used more and more widely. Engineering structural steel has a great risk of corrosion failure for long-term service in seawater, as seawater is a kind of corrosive medium containing various salts. At present, there are few projects and research studies available on the corrosion in the seawater environment of Q390C engineering structural steel, which is used in the Shenzhen–Zhongshan Link immersed tunnel steel shell at home and abroad. It cannot guide the corrosion of immersed tunnel steel shells in the ocean.Originality/valueIn this paper, the corrosion mechanism and corrosion development regulation of marine engineering structural steel in the marine environment are studied by accelerated corrosion test in the laboratory, which is of great significance to ensure the long-life durability of the immersed tunnel in marine engineering.

Purpose This study aims to explore how the inhibitor-loaded nanocontainers can be used in the epoxy coating for protection of steel against corrosion. A self-healing anticorrosive coating can be easily fabricated by embedding the inhibitor-loaded nanocontainers into the epoxy coating matrices. For this purpose, first, cerium (a catholic corrosion inhibitor) is encapsulated into silica nanoparticles (SiO2@Ce). Thereafter, an epoxy nanocomposite coating has been prepared on steel substrate using these SiO2@Ce nanoparticles as nanofillers. Design/methodology/approach To examine the effect of SiO2@Ce nanocontainers on mechanical properties of epoxy coating, the abrasion resistance, impact resistance and adhesion strength of coating have been evaluated. To reveal the effect of SiO2@Ce nanocontainer on corrosion behavior of epoxy-coated steel, the electrochemical impedance spectroscopy (EIS) has been conducted in NaCl solution. Findings Transmission electron microscopy and scanning electron microscopy/Energy-dispersive X-ray spectroscopy analyses indicate that Ce3+ cations have been successfully loaded into the surface of silica nanoparticles (at the content of approximately 2 Wt.%). Mechanical tests of epoxy nanocomposite coatings indicate that the nanocomposite coatings with nanoparticles content of 2.5 Wt.% provide the highest values of abrasion resistance, impact resistance and adhesion strength. EIS results show that the presence of SiO2@Ce3+ nanocontainers increases both coating resistance and polarization resistance. Along with the improvement the coating barrier performance, Ce inhibitor plays an important role in improving the anticorrosive performance at the steel–electrolyte interface. Originality/value The application of self-healing epoxy/SiO2@Ce nanocomposite coatings for the protection of carbon steel is very promising.

Purpose This study aims to examine the corrosion and flexural behaviour of advanced hybrid aluminium matrix nanocomposites (HAMNCs) made with a vacuum-assisted stir die casting (two-layer feeding) and reinforced with titanium oxide (TiO2) and yttrium oxide (Y2O3) nanoparticles. The previous researchers have shown that TiO2 and Y2O3 nanoparticles make aluminium composites much more resistant to corrosion and wear. Design/methodology/approach Salt spray corrosion tests were done on the samples over time as well as the pre-and post-corrosion morphology of the test samples was also investigated. The density, porosity and energy dispersive X-ray of the fabricated samples were observed. Findings It was observed that a lower corrosion rate of 0.127 mils/year and 0.573 mils/year was seen in the Al/5 Wt.%TiO2/5 Wt.%Y2O3 (HAMNC1) and Al/7.5 Wt.%TiO2/2.5 Wt.%Y2O3 (HAMNC3), respectively. It was evident from the results that the pores and densities of the samples varied with the filler concentrations and matrix filler wettability. HAMNC1 has the lowest values of density and porosity at 2.568 g/cm3 and 9.91%, respectively. At the same time, a significant improvement in the flexural strength of 72 N/mm2 was also seen in the HAMNC1 configuration. Practical implications The proposed hybrid samples are well suited for aerospace and automobile structural components such as brake drums, discs, engine cylinders and fins. Originality/value The mixed influence evaluation of TiO2 and Y2O3 nanoparticles with pure Al on composite samples has not been studied. This research aims to examine the combined influence of nanoparticles on the corrosion aspects of two-step feeding vacuum stir casted products, as well as their morphology.