Corrosion Tests Research Articles

An Experimental Study of the Properties of Carbon Fiber/Epoxy Composites Mixed with Rubber Granules

In this research work, the mechanical properties of hybrid composites reinforced with woven carbon fiber mats particulated with natural rubber powders as fillers in the epoxy resin matrix were investigated. The specimens were prepared by the hand-layup process followed by a vacuum bag moulding process. The vacuum moulding reduces the voids or cavities in the hybrid composites. The natural rubber powder was added in different weight proportions (5%, 10%, 15%, and 20%), and carbon fiber is added in 20% for all the specimens. Experiments such as tension testing, flexural testing, water absorption/acid corrosion/base corrosion tests, dynamic mechanical analysis (DMA), and scanning electron microscopic (SEM) analysis were conducted to evaluate the epoxy carbon rubber (ECR) composites. The tensile and flexural test findings demonstrated that the addition of 10% natural rubber particles gave better results as compared with other proportions. The water/acid/base absorption test findings reveal that the ECR composites are not affected by water/acid/base. The DMA teat findings show that ECR composites having 10% natural rubber have higher damping factor, storage, and loss modulus. The SEM analysis shows that ECR hybrid composites with 10% rubber particles contained a uniform distribution of rubber particles over reinforcement, and also, there were no cracks and voids. According to this research findings, ECR hybrid composites with 10% natural rubber particles prepared during the vacuum bag moulding process can be used to prepare aerospace interior components.

Wear and corrosion resistance of Al2O3 and TiC deposition on steel substrate using Self- propagating High temperature Synthesis method

Abstract In the present work, a low-carbon steel substrate was coated with Al2O3 and TiC using self-propagating high temperature synthesis. The synthesized coatings were annealed at 450oC for 2-6 hrs. The characteristics of the substrate, coated, and annealed samples were examined, including microhardness, wear resistance, and corrosion resistance. A pin-on-disc tribometer was employed to conduct the wear test by varying the load, sliding velocity, and distance. The impact of these factors on the wear rate and worn surface morphology was then examined. Further, corrosion resistance was evaluated using electrochemical corrosion testing with 3.5 wt.% NaCl as electrolyte. Results showed that Al2O3 and TiC specimens annealed at 450oC for 5 hrs and 4 hrs improved the microhardness by 1.3 and 1.06 times than that of as-coated specimens respectively. The synthesized Al2O3 and TiC coatings showed an abrasive wear mechanism at higher loads and tribolayer formation was observed at higher sliding velocity and distances. The corrosion and wear resistances of the samples were found as follows: substrate< Al2O3 coated < TiC coated < Al2O3 annealed < TiC annealed. The Al2O3 and TiC ceramic coatings were found to improve wear and corrosion resistance having potential applications in cement, petrochemical, and marine industries.

Comparison of the Erosive Wear Resistance of Ductile Cast Iron Following Laser Surface Melting and Alloying

This article presents research results on the influence of the laser surface melting and alloying processes on the erosive wear resistance of ductile cast iron. For the research, an EN-GJS 350-22 ductile cast iron surface was laser-melted and laser-alloyed with titanium powder in an argon and nitrogen atmosphere. Solid-particle erosion tests were carried out on the laser-melted and -alloyed surface layers and the base material according to the ASTM G76-04 standard with 30° and 90° impingement angles. The erosive wear resistance results were correlated with Vickers hardness and microstructural test results with the use of SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), and XRD (X-ray diffraction). The mechanisms of erosive wear were also analyzed for the laser-treated surface layers and the base material. The research showed that the laser melting and alloying processes with titanium powder had a positive effect on the hardness and erosive wear resistance of the ductile cast iron surface due to microstructure modification. Moreover, despite the lower hardness of the laser-alloyed surface layers, their composite microstructure had a positive impact on the erosive wear resistance in comparison to the laser-melted surface layers.

Performance study of novel metal corrosion probes based on the adjust method of series and parallel connections

Abstract Rod-type metal corrosion probes based on electromechanical impedance (EMI) technique can quantitatively assess the amount of corrosion, which have a promising application in pipeline corrosion monitoring and have received more and more attention. In the design of piezoelectric smart devices, electrical series and parallel connections are very important and effective adjust method to improve the device performance, but it is yet to be used in the probe design. In this work, a kind of novel metal corrosion probe with two piezoelectric elements in series and parallel connections was proposed, and its performance was investigated comprehensively by combining theoretical analysis with experiment research. Theoretical models of the proposed probe in the longitudinal vibration mode for both series and parallel connections were established, and verified by the experimental results. Influences of the thicknesses of piezoelectric layer and ceramic layer on the probe performance were analyzed. Artificial quantitative corrosion tests and accelerated corrosion tests were designed to evaluate the quantitative corrosion monitoring capacity. Temperature sensitivity tests were conducted to study the temperature dependence. The wireless impedance measurement was performed to confirm the online monitoring ability. Comparisons for the probe performance between the series and parallel connections were also presented. This work provided a comprehensive understanding for this kind of novel probe, which is beneficial to develop low-cost, high-precision, high-stability pipeline corrosion real-time monitoring technology.

Improved magnetic-based apparatus enables non-destructive and high sensitive steel-bar corrosion detection

Steel-bar corrosion can not only induce corrosion cracking, but also cause the bearing capacity decline of concrete structures. This contribution reported an improved magnetic-based steel bar corrosion detection apparatus with simple structure and high accuracy. Accelerated corrosion tests on steel rebar were carried out to calibrate the accuracy of the magnetic-based corrosion detection apparatus. A parameter of sensitivity coefficient, k, was proposed to evaluate the corrosion detection sensitivity of the apparatus. An equivalent numerical model was established based on multi-physical simulation to quantify the corrosion degrees and explore the impacts of the frame internal structural parameters. Results show that k is stable and changes linearly with the diameter of steel rods tested. Increasing frame width and foot length can increase k, and adding extra calibration magnetic circuits leads to reduction in k. Overall, the modified magnetic-based apparatus provides a simple, reliable, accurate and non-destructive method for steel corrosion detection.

P21 Advancing dermatological care: a comprehensive evaluation of the steroid-free GL-1 formulation

Abstract Introduction and aims The prolonged use of topical steroids introduces notable dermatological risks, including the onset of permanent stretch marks, bruising, discoloration and vascular abnormalities. This study presents an innovative strategy by formulating GL-1, a steroid-free treatment amalgamating seaweed bioactives, sesame oil and naturally occurring salts and minerals. The objective of this study was to address the limitations of conventional topical steroids and introduce pioneering solutions to dermatological care. Methods To assess the safety and efficacy of GL-1 (product 1), a comprehensive battery of in vitro tests was employed. The skin corrosion test (OECD 431) established the noncorrosive nature of GL-1, validating its safety on reconstructed human epidermis. The skin irritation test (OECD 439) demonstrated the nonirritating attributes of GL-1, aligning with the United Nations Globally Harmonized System of Classification and Labelling guidelines. Additionally, the bovine corneal opacity and permeability test (OECD 437) affirmed the noninducing nature of GL-1 in relation to eye irritation or serious eye damage. Results Preliminary outcomes from dermal clinical trials indicate promising Results for GL-1. In vitro experiments on HaCaT and human dermal fibroblasts, adult (HDFa) cell lines highlighted the noncytotoxicity of GL-1, contrasting with the ‘Cortopin’, which exhibited cytotoxicity. GL-1 exhibited a proliferative effect in HDFa cells, signifying its potential for regenerative applications. Furthermore, both GL-1 and ‘Cortopin’ displayed antioxidant activity in HaCaT cells, underscoring the additional merits of our formulation. Conclusions Our steroid-free formulation, GL-1, demonstrates exceptional safety and efficacy through a meticulous series of in vitro assessments and initial clinical trials. These findings position GL-1 as a promising candidate for diverse dermal applications, offering a secure alternative to traditional topical steroids. The potential impact of GL-1 transcends its therapeutic efficacy, emphasizing its robust safety profile validated through multiple in vitro evaluations.

Tungsten inert gas-assisted surface modification of 1045 steel with SiC particles

AISI 1045 steel is a medium-carbon steel with good strength, hardness, machinability, and weldability. However, it has poor wear and corrosion resistance. This study is an attempt to investigate the feasibility of creating a hard and wear-resistant composite layer on the surface of AISI 1045 steel using SiC particles through the tungsten inert gas (TIG) welding. The SiC powder was mixed with sodium silicate glue and polyvinyl alcohol and then applied to the samples using the TIG welding process. The welding voltage was kept constant at 15 V, and the welding current and welding speed were varied from 85 to 95 A and ∼ 0.5 to 1.8 mm/s, respectively. The powder percentage varied between 10 and 30 wt. %. The microstructural evolutions were studied using an optical microscope, a field emission scanning electron microscope (FESEM) equipped with an energy-dispersive spectroscope (EDS), and X-ray diffraction (XRD). It was observed that the microstructure of the surface-modified samples consisted of a dendritic Fe–Si matrix with carbon masses remaining from the partial dissolution of SiC particles. The effect of heat input on the microstructure was also investigated. The hardness of the surface-modified samples increased by about eight times compared to the base metal, and their wear resistance was notably improved. The results of the electrochemical corrosion tests showed an overall improvement in the corrosion resistance of the coated samples compared to the base metal.

Temporal and Spatial Variation Study on Corrosion of High-Strength Steel Wires in the Suspender of CFST Arch Bridge

The corrosion and degradation behavior of high-strength steel wires during service directly affect the safety and usability of suspenders in steel pipe concrete arch bridges. In this study, three different types of specimens were fabricated using steel wires extracted from the suspenders of an 11-year-old in-service arch bridge and subjected to accelerated corrosion tests with acetic acid. Considering the differential diffusion processes of corrosion factors caused by varying degrees of damage to the suspender sheath, the spatial corrosion variability of steel wires at different positions within the suspender cross-section was investigated. Experimental results indicated a two-stage characteristic in the corrosion process of individual galvanized steel wire samples. In the first corrosion stage, the microstructure on the corroded steel wire surface evolved from a dense crystalline structure to a porous one. In the second corrosion stage, corrosion products accumulate on the steel wire substrate, subsequently further aggregating into sheet-like structures. The maximum pitting factor of individual steel wire samples from a specific area could be described by a Type I extreme value distribution. In the time-dependent model that was established, the location parameter and scale parameter exhibited an exponential decrease during the first corrosion stage and a linear decrease during the second corrosion stage. In the absence of sheath protection, the coefficient of variation in corrosion among adjacent steel wires in the suspender followed a normal distribution. The spatial corrosion variability of the wires inside the suspender is significantly influenced by the shape of the suspender sheath damage. As the corrosion time increased, the overall discrepancy in corrosion levels among different layers of wires diminished.

The Collapse Mechanism of Slope Rill Sidewall under Composite Erosion of Freeze-Thaw Cycles and Water

The composite erosion of freeze-thaw and water flow on slope rills is characterized by periodicity and spatial superposition. When revealing the collapse mechanism of slope rill sidewalls under the composite erosion of freeze-thaw and water flow, it is necessary to fully consider the effect of water migration and its impact on the stability of the rill sidewall. In this paper, we placed the self-developed collapse test system in an environmental chamber to carry out model tests on rill sidewall collapse on slopes under the composite erosion of freeze-thaw and water flow. We utilized three-dimensional reconstruction technology and the fixed grid coordinate method to reproduce the collapse process of the rill sidewall and precisely locate the top crack. We obtained the relationship between the water content of the specimen and mechanical indexes through the straight shear test. The main conclusions are as follows: The soil structure of the rill sidewall is significantly affected by the freeze-thaw cycle, which benefits capillary action in the soil. One freeze-thaw cycle has the most serious effect on the soil structure of the rill sidewall, and the change in the moisture field is more intense after the soil temperature drops below zero. The friction angle of the soil increases with the number of freeze-thaw cycles and tends to stabilize gradually. The effect of the freeze-thaw cycle on the rate of change of the water content of the soil at each position of the wall can be accurately described by a logarithmic function. The expression of the two-factor interaction effect on the rate of change of water content of soil at each position of the rill sidewall can be accurately fitted. We propose a calculation system for locating cracks at the top of the rill sidewall and determining the critical state of instability and collapse of the rill sidewall during the process of freeze-thaw and water flow composite erosion. The results of this research can help improve the accuracy of combined freeze-thaw and water flow erosion test equipment and the development of a prediction model for the collapse of the rill sidewall under compound erosion. This is of great significance for soil and water conservation and sustainability.

A comprehensive investigation of uncertainties in cavitating waterjet experiments

This paper systematically examines the sources of uncertainty in cavitating waterjet test setups and provides illustrative case studies to conduct thorough uncertainty analyses for erosion tests using cavitating waterjet method. Within this study, utilizing examples of uncertainty analysis presented by the International Towing Tank Conference (ITTC) for various testing techniques, a novel uncertainty analysis implementation suitable for cavitating waterjet tests has been conducted. Firstly, cavitation erosion experiments were carried out on samples aluminum (Al 6063) material under cavitation number conditions (σ = 0.02 to σ = 0.033 range) as part of the validation study. Subsequently, within the scope of uncertainty analysis calculations, five erosion tests were conducted for each of the two different cavitation numbers (σ = 0.03 and σ = 0.05). The study aims to examine the bias and precision uncertainty components separately for the test results of erosion rate and establish a reliable and repeatable procedure for predicting the uncertainty level of cavitating waterjet tests. For the first time in the literature, the uncertainty components of cavitating waterjet tests were investigated in detail and the uncertainty level in cavitating waterjet tests, including bias and precision errors, was predicted in accordance with specific ITTC guidelines and procedures. Based on the results, the primary bias error source was identified as the pressure inside the cavitation chamber, with the nozzle pressure being the second most significant bias error source. Consequently, it is recommended to perform the bias error prediction based on the ratio of these two, known as the cavitation number. Precision error, crucial for uncertainty, was estimated using five sets of erosion rate values, emphasizing its importance in cavitating waterjet tests. It is anticipated that the suggested methodology will serve as a benchmark for predicting uncertainty levels in cavitating waterjet tests.

Investigation of corrosion resistance and interfacial bonding properties of silver/silicone zinc-rich coating/substrate system in marine environment

This paper aims to study the corrosion resistance and interfacial bonding properties of the silver zinc-rich coating/substrate system and silicone zinc-rich coating/substrate system. The actual working state of the system in marine environment was simulated by the coupled effects of corrosion and pre-stretching. Scanning electron microscope (SEM) with an energy dispersive X-ray spectrometer (EDS) was used in corrosion test to analyze the surface morphology and corrosion products. Meanwhile, the degradation degree of the corrosion resistance was investigated based on the electrochemical impedance spectroscopy (EIS) and water absorption rate. Three-point bending test and tensile test combined with digital image correlation (DIC) were performed to evaluate the interfacial bonding properties of these two systems based on the elastic modulus and critical cracking strain. Results show that the dense accumulation of aluminum and zinc powders makes the silver zinc-rich coating have higher corrosion resistance compared to the silicone zinc-rich coating. The combined effects of corrosion and pre-stretching on the fracture toughness of silicone zinc-rich coating are larger than that of the silver zinc-rich coating. The interfacial bonding properties of the coating/substrate systems gradually degrade as the pre-stretching load approaches the critical cracking load of the coating.

Corrosion Rate and Mechanism of Degradation of Chitosan/TiO2 Coatings Deposited on MgZnCa Alloy in Hank’s Solution

Corrosion Rate and Mechanism of Degradation of Chitosan/TiO2 Coatings Deposited on MgZnCa Alloy in Hank’s Solution

Study on the preparation of SiC–C–t‐ZrO2 composites and its corrosion resistance to crushed after‐used lithium batteries

AbstractIn order to solve the severe erosion of kiln refractories for the high‐temperature treatment used during the process of recovering valuable metal elements from waste lithium batteries, this study investigates the low‐cost, no‐firing preparation technology of erosion‐resistant SiC–C–t‐ZrO2 composites with self‐prepared t‐ZrO2–SiC–C powder, as well as silicon carbide and flake graphite as the main raw materials, and phenolic resin as the binding agent. (1) The effects of different t‐ZrO2–SiC–C powder additions and heat treatment temperatures on the properties of SiC–C–t‐ZrO2 composites were studied in details. (2) The erosion resistance of SiC–C–t‐ZrO2 composites to after‐use lithium battery waste was evaluated using the static crucible method. The mechanical properties of the t‐ZrO2–SiC–C composites was the best that its cold modulus of rupture (CMOR) was 11.37 MPa and cold crush strength (CCS) was 41.96 MPa when heat treatment temperature was 600°C and content of t‐ZrO2–SiC–C powder was 10 wt%. At that condition, the bulk density of samples reached to 3.15 g/cm3 and apparent porosity of it was only at 11.09% which means that the samples designed in this work are compacted enough. In the erosion test, the t‐ZrO2–SiC–C composites had an excellent resistance to erosion of lithium battery waste.

A comparative study of electric current-assisted and conventional sintering of Inconel 718 superalloy

AbstractIn this study, In718 powder mixtures prepared from elemental powders following stoichiometric composition and supplied as a commercial product were produced by conventional powder metallurgy (1300 °C/4 h) and electric current-assisted sintering (ECAS)(1700-2300A/10 min) methods and followed by a double-aging heat treatment. The characterization studies determined that the best results were the sample produced by the ECAS method using the elemental powder mixture. The targeted precipitate γ′, γ″, and δ phases were obtained after the heat treatment, and a hardness value of 344 ± 41 HV0.5 and a relative density of 98.96% were achieved. The sample preserved its surface integrity by exhibiting high corrosion resistance from hot corrosion studies in the temperature range of 650–850 °C and NaSO4 + 60%V2O5 environment. The corrosion rate of the sample, which was subjected to electrochemical corrosion tests in 3.5% NaCl and 10% NaNO3 solutions, was determined as 45.59 mpy and 10.56 mpy, respectively.

Fabrication of diisocyanate microcapsules for self-healing anti-corrosion coatings via integrating electrospraying and interfacial polymerization

Epoxy resins serve as useful material in anti-corrosion coatings. However, the development of microcracks during the processing or service life of a coating is an inevitable occurrence that markedly degrades its performance and shortens its lifespan. The incorporation of self-healing materials can prolong the coatings' lifespan and enhance the reliability of corrosion prevention processes. In this study, a microencapsulation method via integrating electrospraying and interfacial polymerization (ES-IP) was adopted to synthesize the microcapsules containing 4,4’-bis-methylene cyclohexane diisocyanate (HMDI) successfully. The self-healing capability of these microcapsules within the anti-corrosion coating was successfully validated. The prepared HMDI microcapsules (HMDI-MCs) demonstrate excellent dispersibility, tunable characteristics, and a high core material content of 93 wt%. Self-healing anti-corrosion coatings containing HMDI-MCs were prepared and underwent accelerated corrosion testing in sodium chloride (NaCl) solution. The result showed that HMDI is capable of leaking from microcapsules and undergoing solidification, thus forming a barrier to metal steel from corrosion hazards by endowing the coatings with effective self-healing abilities. This paper expands the application of the ES-IP technique in microencapsulation and suggests that HMDI-MCs have significant potential in self-healing anti-corrosion coating.

The Impact of Plasma Surface Treatments on the Mechanical Properties and Magnetic Performance of FDM-Printed NdFeB/PA12 Magnets

This study presents a novel approach for improving the interfacial adhesion between Nd–Fe–B spherical magnetic powders and polyamide 12 (PA12) in polymer-bonded magnets using plasma treatments. By applying radio frequency plasma to the magnetic powder and low-pressure microwave plasma to PA12, we achieved a notable enhancement in the mechanical and environmental stability of fused deposition modeling (FDM)-printed Nd-Fe-B/PA12 magnets. The densities of the FDM-printed materials ranged from 92% to 94% of their theoretical values, with magnetic remanence (Br) ranging from 85% to 89% of the theoretical values across all batches. The dual plasma-treated batch demonstrated an optimal mechanical profile with an elastic modulus of 578 MPa and the highest ductility at 21%, along with a tensile strength range of 6 to 7 MPa across all batches. Flexural testing indicated that this batch also achieved the highest flexural strength of 15 MPa with a strain of 5%. Environmental stability assessments confirmed that applied plasma treatments did not compromise resistance to corrosion, evidenced by negligible flux loss in both hygrothermal and bulk corrosion tests. These results highlight plasma treatment’s potential to enhance mechanical strength, magnetic performance, and environmental stability.

The interaction between Aspergillus brasiliensis and exposed copper circuits in the space microgravity environment

In the space station, filamentous fungi are one of the main potential hazards causing short circuits or corrosion failure of printed circuit boards (PCBs). A 90-day fungal corrosion test was carried out on the China Space Station (CSS), focusing on the interaction between A. brasiliensis and exposed copper circuits. The results showed that the mycelial morphology, ultrastructure, and organic acid accumulation of the test fungi exhibited significant changes in the space microgravity environment. Aspergillus brasiliensis tended to excrete higher levels of oxalic acid in space as a defense mechanism against copper toxicity, which could exacerbate localized corrosion of copper metal.

Nanosilica from canary seed husk for corrosion protection of structural steel

AbstractAn alternative technique is presented for the corrosion protection of the A36 structural steel (A36SS) in acid medium (H2SO4) using silica obtained from canary seed husk (CSH). The silica was obtained in a solid amorphous state with a particle size of 10–22 nm. The anticorrosive properties of nanosilica (NS) were studied using potentiodynamic polarization (PDP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS). Before carrying out the corrosion tests, the A36SS was subjected to a treatment with NaOH solution without and with the presence of NS. The A36SS treated with NS presented the lowest current density values and the noblest corrosion potential values, indicating that the corrosion rate decreased. The surface morphological study of the tested systems using SEM/EDS showed that the NS‐treated A36SS had a more efficient physical barrier against corrosive species.

In-situ formation of Zn-MOF coating on MgO/HA composite layer produced by plasma electrolytic oxidation on Mg-Sn-Mn-Ca alloy for orthopedic internal fixation devices

ABSTRACT A novel ultra-sound assisted method was used to grow zinc-metal organic framework (Zn-MOF) film on magnesium oxide/hydroxyapatite (MgO/HA) composite layer developed using plasma electrolytic oxidation (PEO) on Mg-5Sn-0.2Mn-0.2Ca alloy. The microstructure surface roughness and microhardness tests were performed on the samples to evaluate the mechanical properties of the coatings. The electrochemical corrosion test was performed to evaluate the corrosion resistance of the coated Mg alloy. Further, an in-vitro bioactivity test was performed to study the biocompatibility and bioactivity of the coated alloy, which is an essential aspect of biomedical applications. Results showed that the MgO/HA composite coating was helpful in the in-situ growth of the Zn-MOF particles by mechanically interlocking them. Further, incorporating hydroxyapatite in the coating could also increase the bioactivity. The study also confirmed that the bi-layer coating of Zn-MOF on the MgO/HA composite layer improved the surface roughness, hardness, biocorrosion resistance, and bioactivity making it more likely to be used for orthopedic internal fixation devices.

Application of MgO/ZrO2 coating on 309 stainless steel to increase resistance to corrosion at high temperatures and oxidation by an electrochemical method

Abstract 309 stainless steel is one of the steels that have the highest resistance to corrosion and thermal oxidation compared to other steel grades, but it should not be used at temperatures higher than 980°C if there are temperature fluctuations. Additionally, 309 stainless steel is not designed for use in wet environments and has the least corrosion resistance. This study aims to cover 309 stainless steel with MgO/ZrO2 particles using a two-step electroplating deposition method and then sintering to increase its resistance to wet corrosion and oxidation in temperature fluctuations. The intermediate ZrO2 coating makes the outer MgO layer about two times thicker and reduces the corrosion current density. The morphology of the coatings was determined using scanning electron microscopy and X-ray diffraction, and oxidation resistance was determined using cyclic oxidation tests and the wet corrosion test of the corrosion solution. 3.5% NaCl was used. The results showed that the coated samples, due to the use of TiO2 middle layer and MgO protective layer in the electrochemical method, have a 2-fold increase in wet corrosion and an increase in hardness of about 77%, as well as an increase in oxidation resistance of 1.8% compared to the sample without coating. Also, the reason for using the electrochemical deposition method is for better surface smoothness and less porosity of the coating as well as its use on all metals compared to thermal spray methods.