Painted Steel Research Articles

Novel antifouling paint formulation based on Ca2​Cr2O5​ and CaMnO3​ NPs as a protective pigment

This work focused on the preparation of novel antifouling paint based on Ca2Cr2O5 and CaMnO3 NPs as a safe protective pigment which were replaced with cuprous oxide. Three paint formulations were prepared for comparison, a blank formula without an antifouling agent (F1), a commercial antifouling formula based on 100% cuprous oxide as an antifouling agent (F2), and AF formula based on 75% Ca2Cr2O5 and CaMnO3 NPs and 25% Cu2O. The high performance and durability of the paints based on the prepared pigments were evident from their impact resistance, adhesion, pending, hardness, and chemical resistance, which were compared to the blank formula (F1). The corrosion resistance of the painted films was also investigated using the salt spray test method, and the results were promising compared to the blank and standard formulations. All painted steel plates were exposed to seawater through field tests in the Suez Canal at Port Said for up to 6 months. The results showed that the paints based on F2 and F3a, b enhanced the antifouling activity through six months of exposure. The obtained results demonstrated greater efficiency of the painted steel-based F3a than F1 and F3b, and being comparable to the standard formula (F2).

Advancing Sustainability: Geraniol-Enhanced Waterborne Acrylic Pressure-Sensitive Adhesives without Chemical Modification.

The escalating global emphasis on sustainability, coupled with stringent regulatory frameworks, has spurred the quest for environmentally viable alternatives to petroleum-derived materials. Within this context, the adhesives industry has been actively seeking renewable options and eco-friendly synthesis pathways. This study introduces geraniol, a monoterpenoid alcohol, in its unmodified form, as a key component in the production of waterborne pressure-sensitive adhesives (PSAs) based on acrylic latex through emulsion polymerization. Multiple formulations were developed at varying reaction times. The adhesives underwent comprehensive chemical characterization employing techniques such as Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Nuclear Magnetic Resonance (NMR), Gel Permeation Chromatography (GPC), and dynamic light scattering (DLS). The viscosities of the formulations were measured between 4000 and 5000 cP. Adhesion tests showed peel strength values of 0.52 N/mm on cardboard and 0.32 N/mm on painted steel for the geraniol-based formulations. The results demonstrate the potential for geraniol-based PSAs to offer a sustainable alternative to petroleum-derived adhesives, with promising thermal and adhesive properties.

Monitoring under-coating corrosion of painted structural steel with no-core fiber optic sensors

No-core fiber (NCF) optic sensors are employed to monitor the under-coating corrosion of painted structural steel for the first time considering three different diameters. The optic sensors were installed on painted structural steel plates which were submerged in a 3.5 wt% sodium chloride solution. The transmission spectral shift and the corrosion progression of the painted steel plates were measured simultaneously. Visual observation was also conducted with a scanning electron microscope. The results indicate that the dip wavelength of optic sensors varies as the immersion time increases. The shift in the dip wavelength is linearly correlated with the coating damage indices, and this correlation can be utilized to monitor under-coating corrosion in painted structural steel. The diameter of NCF fiber sensors has no significant effect on the monitoring sensitivity. The monitoring sensitivity for the coating damage index is approximately 1.00 nm shift of the dip wavelength corresponding to 1% coating damage.

Root causes for corrosion on painted steel structures in marine environments

AbstractOur understanding of the failure mechanisms of coatings, for example, cathodic disbonding, corrosion creep, blistering, and cracking, have been developed to a high level over the past decades. However, knowing what actually causes coatings to fail in the field is also important. Several atmospheric field tests of coating with duration 2–9 years have been published, showing that epoxy‐based heavy‐duty protective coating systems with zinc‐rich primers have high resistance against corrosion creep from damages in the coating. Despite this, scribe creep corrosion has become the most important evaluation parameter in standardized testing. In this work, inspection pictures from an offshore oil and gas platform, a ballast water tank system, and two coastal road bridges have been analyzed with respect to the root cause for initiation of corrosion on coated steel. The results show that corrosion mainly initiates at edges and welds. Between 50% and 90% of the corrosion attacks could be attributed to this, depending on the type of structure. The paint failed due to low film thickness, that is, the wet paint retracts from sharp edges in the surface so that the cured film has reduced barrier properties.

Mercaptosilane as additive orpretreatment in acoating system for steel

The application of paints is one of the most used protection methods for metals, but the loss of adhesion of the paint film is a commonly observed failure. In order to avoid this deterioration different silanes are studied as adhesion promoters between paints and metals.The aim of this paper was to study the adhesion promotion of mercaptopropyl-trimethoxysilane in a protection system for steel. Two strategies were used in order to incorporate the silane: as an additive in an epoxypolyamide water-borne paint, and as a pretreatment before painting. Adhesion tests were performed during exposure of the painted steel panels in the salt spray chamber. Blistering and rusting degrees were also evaluated during the panel's exposure in the salt spray and humidity chambers. Besides, electrochemical (corrosion potential measurements and ionic and polarization resistances) and service exposure tests were performed.The results show that depending on the environmental conditions, it is better to incorporate the silane in the paint or as a pretreatment. Moreover, the results also depend on the silane concentration and the time of hydrolysis before pretreatment or its incorporation in the paint.

Comparative study between natural and artificial weathering of acrylic‐coated steel, aluminum, and galvanized steel

AbstractSince testing organic coatings under natural conditions is a time‐consuming process, accelerated methods are needed to produce results in less time. A simulated environment cannot fully reproduce actual operating conditions, so it is important to investigate the correlation between accelerated and natural aging test results. In this article, the natural aging of painted steel, aluminum, and hot‐dip galvanized steel is studied for 1 year under continental climate conditions. The environmental parameters responsible for the change of the protective system in a continental urban environment were monitored: time of wetness, ultraviolet radiation, and temperature. The extent of deterioration is compared with similar samples weathered by accelerated testing using electrochemical impedance spectroscopy, differential scanning calorimetry, and gloss measurements. Neutral salt spray chamber, prohesion test, immersion in a quiescent salt solution, and ultraviolet B‐rays (UVB) exposure test are considered. The results of the accelerated cabinet tests are discussed, and the effect is evaluated for the various coated metals. This study highlights the major problems encountered in building a model to predict durability in such a critical area as the durability of organic coatings for metal structures.

Corrosion resistance of graphene/basalt flake modified waterborne epoxy zinc-rich primer

PurposeThe purpose of this study is to evaluate the effect of graphene, basalt flakes and their synergy on the corrosion resistance of zinc-rich coatings. As the important heavy-duty anticorrosion coatings, zinc-rich coatings provided cathodic protection for the substrate. However, to ensure cathodic protection, a large number of zinc powder made the penetration resistance known as the weakness of zinc-rich coatings. Therefore, graphene and basalt flakes were introduced into zinc-rich coatings to coordinate its cathodic protection and shielding performance.Design/methodology/approachThree kinds of coatings were prepared; they were graphene modified zinc-rich coatings, basalt flakes modified zinc-rich coatings and graphene-basalt flakes modified zinc-rich coatings. The anticorrosion behavior of painted steel was studied by using the electrochemical impedance spectroscopy (EIS) technique in chloride solutions. The equivalent circuit methods were used for EIS analysis to obtain the electrode process structure of the coated steel system. Simultaneously, the corrosion resistance of the three coatings was evaluated by water resistance test, salt water resistance test and salt spray test.FindingsThe study found that the addition of a small amount of graphene and basalt flakes significantly improved the anticorrosion performance of coatings by enhancing their shielding ability against corrosive media and increasing the resistance of the electrochemical reaction. The modified coatings exhibited higher water resistance, salt water resistance and salt spray resistance. The graphene-basalt flakes modified zinc-rich coatings demonstrated the best anticorrosion effect. The presence of basalt scales and graphene oxide in the coatings significantly reduced the water content and slowed down the water penetration rate in the coatings, thus prolonging the coating life and improving anticorrosion effects. The modification of zinc-rich coatings with graphene and basalt flakes improved the utilization rate of zinc powder and the shielding property of coatings against corrosive media, thus strengthening the protective effect on steel structures and prolonging the service life of anticorrosion coatings.Originality/valueThe significance of developing graphene-basalt flakes modified zinc-rich coatings lies in their potential to offer superior performance in corrosive environments, leading to prolonged service life of metallic structures, reduced maintenance costs and a safer working environment. Furthermore, such coatings can be used in various industrial applications, including bridges, pipelines and offshore structures, among others.

녹 면적율과 부식피트 형상비를 이용한 도장강재의 인장강도 추정법

녹 면적율과 부식피트 형상비를 이용한 도장강재의 인장강도 추정법

Photocatalytic and Protective Thin Films for Enhanced Self‐cleaning Activity and Durability of Painted Steel Roofings

AbstractFouling of painted steel roofings over time due to biological organisms and other pollutants is a well‐known aesthetic, functional and environmental problem that highlights the importance of developing greener self‐cleaning technologies for roofing applications. Accordingly, a series of novel photocatalytic coating systems have been developed in this study by introducing a copolymer of tetratethyl orthosilane and methyltrimethoxysilane as the photochemically stable binder and intermediate protective layer. Visible light active carbon doped titanium dioxide and surface modified nano titanium dioxide with anatase‐rutile hetero junctions were used as the semiconductor photocataysts. The concentration of titanium dioxide was set as 10 %, 25 % and 40 % by weight of the dried photocatalytic film. Methylene blue photoderadation reaction kinetics and antimicrobial assays were used as the key measures of assessing the self‐cleaning performance. The morphological and chemical composition changes were analyzed as a function of time using scanning electron microscopic and spectroscopic techniques as a measure of service life of these putative photocatalytic coating systems. According, a high degree of self‐cleaning activity was observed in these novel photocatalytic coating systems having 10 % (w/w) to 40 % (w/w) titanium dioxide loading compared to the painted steel roofing control sample. A complete eradication and 2–3 orders of log reduction were achieved respectively against E.coli bacteria and A.niger and Cladosporium fungies. The introduction of the intermediate polysiloxane protective layer has significantly enhanced both the self‐cleaning activity and service life, minimizing the diffusion of photogenerated reactive oxygen species into subsequent underneath paint layers. The photocatalytic self‐cleaning activity and the rate of photodegradation have been increased with titanium dioxide concentration. The coating system with 10 % (w/w) surface modified nano titanium dioxide loading having the intermediate protective layer was found to be the optimum coating formulation to obtain a high degree of self‐cleaning activity at a minimum rate of photodegradation in this study.

Polyhexamethylene guanidine molybdate as an efficient antibacterial filler in epoxy coating for inhibiting sulfate reducing bacteria biofilm

Readily synthesized and highly antibacterial polyhexamethylene guanidine molybdate (PHMG-MoO4) can be used as a filler to greatly improve the resistance of epoxy coating to sulfate reducing bacteria (SRB) biofilm. In SRB inoculated medium, no SRB biofilm formed on PHMG-MoO4/epoxy coating after 120 days, and the corrosion current density of the epoxy coating painted carbon steel decreased by 99.0 % after addition of PHMG-MoO4 in the coating. There were also fewer fouling organisms on PHMG-MoO4/epoxy coating after 4 months of immersion in the actual seawater. The PHMG-MoO4 with low water solubility can remain in epoxy coating for a long time and therefore effectively and continuously inhibited the bacteria on the coating.

THAI experiments on iodine behavior in a room chain representing flow conditions in large containments

Iodine which can be released into the containment during a severe accident, is considered one of the most important nuclides with potential for public dose. Significantly different iodine concentrations can be expected in the individual compartments and rooms of large containments, due to geometrical constraints and the strong dependence of many iodine reactions on local thermohydraulic conditions. Such inhomogeneity may be relevant for organic iodide formation which depends on the concentration of deposited I2 and the dose rate.The objective of the two tests Iod-33 and Iod-35 was to measure the distribution of iodine along a convective flown-through room chain. This arrangement shall simulate the pathway of iodine from the locations of release (primary loop rupture) or formation (sump) along the plant rooms up to the dome of the containment and back. With respect to iodine, the aims were to measure the distribution and mixing of gaseous iodine in different rooms, the decrease of gaseous iodine by its deposition on painted surfaces, and the distribution of deposited iodine on the different painted surfaces.The two tests were performed in the two vessel THAI+ facility with additionally installed painted surfaces (painted with Gehopon epoxy paint) under superheated and condensing conditions. The main part of the painted surface area was provided in the form of painted steel sheets and arranged to form two intermediate floors within the THAI test vessel including small flow openings. Gaseous iodine was injected over several hours into the room chain in which a slow convection was established by means of differential wall heating.The gaseous I2 concentration inside the THAI+ facility increased continuously until the I2 injection was terminated. Simultaneously, the iodine deposition onto the painted surface increased. The gaseous I2 concentration decreased rapidly after stopping the I2 injection, in favor of a continuation of the I2 deposition on painted surfaces. The multi-compartment effect along the room chain has been demonstrated by the test results and the data allows for further development and validation of the I2/paint reaction model of severe accident codes.

Convolution Neural Network with Laser-Induced Breakdown Spectroscopy as a Monitoring Tool for Laser Cleaning Process.

In this study, eight different painted stainless steel 304L specimens were laser-cleaned using different process parameters, such as laser power, scan speed, and the number of repetitions. Laser-induced breakdown spectroscopy (LIBS) was adopted as the monitoring tool for laser cleaning. Identification of LIBS spectra with similar chemical compositions is challenging. A convolutional neural network (CNN)-based deep learning method was developed for accurate and rapid analysis of LIBS spectra. By applying the LIBS-coupled CNN method, the classification CNN model accuracy of laser-cleaned specimens was 94.55%. Moreover, the LIBS spectrum analysis time was 0.09 s. The results verified the possibility of using the LIBS-coupled CNN method as an in-line tool for the laser cleaning process.

Use of seawater to improve the static strength and fatigue life of bonded coated steel joints

Shipbuilding industry is demanding adhesive solutions for joining components to painted substrates, as traditional welding technologies require costly and time consuming processing operations. However, this topic is rarely considered in the literature. The aim of the current study is to investigate the influence of sodium chloride solution on the static strength and fatigue performance of adhesively bonded painted steel joints. To achieve this, a brittle two component epoxy adhesive was used to manufacture single lap adhesively bonded painted steels. Static and fatigue tests were performed after ageing the joints by immersion in chloride solutions for different periods of time. The results surprisingly show that both the static and fatigue mechanical properties of the joints increase significantly with ageing during the first month of the exposure. The water diffusion taking place for the first month at the single lap joints improved more than 30% both the static and fatigue strength of joints manufactured with this relatively rigid adhesive. The water absorption rate of the adhesive was also calculated using Fick's law relations. The results were used to numerically simulate the humidity level within the adhesive layer in bonded joints.

Preparation and evaluation of high-performance modified alkyd resins based on 1,3,5-tris-(2-hydroxyethyl)cyanuric acid and study of their anticorrosive properties for surface coating applications

Abstract By partially substituting 1,3,5-tris-(2-hydroxyethyl) cyanuric acid for glycerol as the polyol, new modified alkyd resins having a wide range of oil length and hydroxyl content were produced. FT-IR, 1H NMR, acid and iodine values, and other characterization techniques were used to confirm the chemical compositions of the modified alkyd resins. The drying qualities of the alkyd resins synthesized were significantly enhanced by adding a greater quantity of freshly prepared polyol and excess –OH, along with improvements in flexibility, gloss measurement, gloss measurement, and scratch hardness, in comparison to unaltered alkyd resin (blank). The corrosion resistance of dried coated steel panels was examined using a salt spray test. By using a specifically designed modified alkyd resin as a binder, the corrosion resistance of painted steel panels was improved. The addition of the new polyol, which contains nitrogen components, as well as the alkyd resins that provide strong adherence to the steel surface, may be responsible for such an improvement.

A bout with the law: Marco Cianfanelli’s representation of Nelson Mandela in Shadow Boxing

A sculpture that is more than five metres high and constructed from laser-cut painted steel, Marco Cianfanelli’s Shadow Boxing (2013) refers to a photograph taken by Drum photographer Bob Gosani in 1957 that shows a young Nelson Mandela sparring with Jerry Moloi, a boxing champion. Placed outside the Magistrates’ Court in Johannesburg, where a young Mandela defended his clients, Shadow Boxing is also just opposite Chancellor House, where Mandela and fellow activist Oliver Tambo had their law offices between 1952 and 1960. Functioning together with the space, Shadow Boxing invokes a sense of Mandela’s experiences in the 1950s while simultaneously encouraging insights and reflections about the ways in which apartheid histories have had impact on the present. Inviting a metaphorical reading of Mandela’s engagement with the law by being placed outside the Magistrates’ Courts as well as his own law offices, Shadow Boxing, it is suggested, also encourages associative interpretations through its formal and material properties. It is argued that, while it depicts a well-known individual on a large scale, Shadow Boxing encourages a more participative and mnemonic engagement than is usual in public statuary.

Remediation of Fouling on Painted Steel Roofing via Solar Energy Assisted Photocatalytic Self‐Cleaning Technology: Recent Developments and Future Perspectives

Rainwater harvesting on rooves is a sustainable solution for global water scarcity. The contamination of roofing materials due to biological organisms and other environmental pollutants limits the utilization of roof harvested rainwater for domestic and industrial applications. Similarly, roof contamination leads to several aesthetic, functional, and environmental concerns highlighting the importance of developing green self‐cleaning technology for roofing applications. Solar‐energy‐driven semiconductor‐based photocatalytic self‐cleaning coatings are a promising approach to minimizing roof contamination against both biological and non‐biological pollutants. However, the development of such technology on painted steel substrates for long‐term outdoor applications has become limited due to the number of challenges are analyzed in this review. Accordingly, challenges, recent developments, and future perspectives of developing and evaluating the performance of photocatalytic self‐cleaning coating systems for roofing applications have been critically reviewed in this article analyzing the research findings of recent studies.

Analysis of Cotton (Gossypium hirsutum) Seed Properties for Engineering Applications

Cotton is cultivated worldwide covering 32.5 million hectares of cultivable land. Cotton seed are valuable raw input to seed and oil industry. Seed properties are essential requirement for design of equipment used in farm, post-harvest processing, storage, cotton ginning as well as seed industries. Computer simulation study needs basic properties as input. The engineering properties were evaluated for five majorly cultivated cotton cultivars of India. Significant difference in properties was observed between varieties. The results defined cotton seed as a non-spherical particle with length, width and thickness varying between 6.05 to 10.99 mm, 3.73 to 6.91 mm and 2.94 to 5.73 mm respectively. Higher frictional force is generated when it interacts with painted mild steel, wood and rubber than PVC, stainless steel and aluminum. Reynolds number indicates transitional flow of cotton seed and coefficient of restitution identifies it between elastic and plastic body.

Effect of ortho-phosphoric acid doping concentration on electrochemical properties of polyaniline coated low carbon steel

Conducting polyaniline-based paint formulation is prepared and coated on the low carbon steel samples. Characterization of conducting polyaniline showed the characteristic peak at 327 nm and a weak broad peak at 608 nm under UV–Vis’s spectrometry. The effect of doping level on electrochemical performance of conducting polyaniline painted low carbon steel was studied using ortho-phosphoric acid as a dopant. All polyaniline-based painted steel samples exhibited a shift in corrosion potential positively and a reduction in corrosion rate. However, the corrosion rate of 0.3 M ortho- phosphoric doped conducting polyaniline coated low carbon steel sample is found to be 0.01 mpy, significantly lower than that of painted and unpainted samples. Higher impedance modulus, coating resistance, and lower coating capacitance confirm the corrosion resistance of 0.3 M ortho-phosphoric doped conducting polyaniline coated low carbon steel sample in a neutral medium. It reveals that doping plays an essential role in the electrochemical performance of the painted steel samples and protects the steel by a barrier and anodic protection.

The use of quality tools to reduce surface defects of painted steel structures

The article presents the results of the use of quality instruments – tools and techniques – in order to reduce surface defects of steel structures on the example of a selected element – engine cover of asphalt milling machines. The article shows the potential of using selected quality tools – basic and new – in the service of quality analysis and improvement. Quantitative analyzes were presented out using the Pareto-Lorenz diagram and the c control chart, qualitative analyzes using the Ishikawa diagram and the FMEA method, quantitative & qualitative analyzes using the interrelationship diagram and matrix diagram, and it was proposed quality improvement using qualitative tools such as affinity diagram, and PDPC diagram. The most common defects of painted surfaces turned out to be improper thickness and surface contamination. As it has been shown, the experience of employees is largely responsible for the cause of these defects, which was also confirmed by other analyses carried out with the use of quality tools. The training was the most frequent method of prevention. It has also been shown that special attention should be paid to quality control, its effectiveness, and quantity. The article proves that correctly used quality tools can contribute to the improvement of the quality of manufactured products, helps in solving various quality problems.

Evaluation of synergic methods for corrosion protection of reinforced steel

PurposeThis study aims to evaluate the effect of pH on the reinforced concrete steel protection for rebars coated with paint formulations containing talc and free from it. As the presence of talc in paints can offer high pH which cordially affects the protection behavior of the coated rebars. Additionally, this study includes evaluating the durability of concrete mixes in presence of some replacements of ordinary cement such as meta-kaolin (MK) and ground granulated blast furnace slag (GGBFS).Design/methodology/approachTwo paint formulations were prepared containing the same ingredients except that (P1) is free from talc and (P2) contains talc. The anticorrosive behavior of painted steel in the blended concrete mixes containing MK and GGBFS was studied by using different electrochemical techniques in chloride solution. The concrete durability was evaluated by the means of compressive and bond strength beside chloride permeability. Different concrete mixes containing mineral groups or pozzolanic materials were prepared by replacing (10, and 30%) GGBFS and (5, 10 and 15%) MK as binary from cement CEM I with (w/b) 0.45 with superplasticizer ratio (SP) 2% of the binderFindingsIt was found that the presence of talc, in spite of its ability to offer high pH, has affected positively the corrosion behavior of reinforced concrete steel by forming a complex with concrete even if it is present in paint formulation and not free in the medium.Originality/valueThe results revealed that concrete blended with (30% GGBFS and 10% MK) with coated rebars with P2 containing talc showed the highest corrosion protection performance in addition to modified permeability and compression resistance.