Anticorrosive Pigments Research Articles

МОРФОЛОГІЯ ТА ТЕРМІЧНА СТІЙКІСТЬ СИНТЕТИЧНОГО ЦЕОЛІТУ, МЕХАНОХІМІЧНО МОДИФІКОВАНОГО КАТІОНАМИ Ca, Zn I Mn(II)

An important direction of new technologies of corrosion protection of metals is the use of inhibitory pigments in the composition of paints and varnishes, which are tolerant to the environment, have high efficiency and can replace chromates. Promising anti-corrosion pigments for paints and varnishes are ion-exchange substances, in particular modified zeolites, which will provide optimal selective resistance to aggressive environmental influences. In this work the dispersion and morphology of complex pigments based on synthetic zeolite and monophosphates of calcium, zinc and manganese are investigated. It was found that the modification of zeolites by metal monophosphates by mechanochemical method in a ball mill for 60 min at a speed of 200 rpm leads to decrease in fraction to 2.0 μm by ~44%… 64% and an increase from 2.0 to 10.0 μm by ~60%. The fraction up to 2.0 μm is represented by particles of irregular globular shape > 10.0 μm - agglomerates. Thermogravimetric studies have shown that all synthesized complex pigments are characterized by thermal stability. Thermolysis is characterized by 4 stages, which correspond to the removal of physically adsorbed water, chemically sorbed water, dehydroxylation of the surface by cleavage of OH groups, and phase transitions. Modification with metal monophosphates increases the thermal stability of pigments in the sequence Na-A: Ca(H2PO4)2 - Na-A: Zn(H2PO4)2 - Na-A: Mn(H2PO4)2. Thermolysis of samples in the temperature range from 15 to 700 °С is took place during four stages, most intensively at temperatures up to 400 °С. During mechanochemical dispersion of zeolites with calcium, zinc and manganese monophosphates, the amount of physically adsorbed water increases by ~18… ~41%, and chemically sorbed water decreases by ~19… ~41%. The specific surface area of zeolite Na-A: Ca(H2PO4)2 increases by ~8%, and Na-A: Zn(H2PO4)2 and Na-A: Mn(H2PO4)2 decreases by ~50% and ~22%, respectively. This may be due to the radii of the metal cations and the fraction content up to 2.0 μm when grinding zeolites. Based on the obtained results, the synthesized zeolites can be recommended for further studies of their inhibitory properties as pigments in the composition of paints and varnishes.

Aluminium alloy corrosion inhibition by a two-stage modified nanoporous zeolite

ABSTRACT A two-stage synthesis of anti-corrosion pigments based on synthetic zeolites was performed. New pigments retain the zeolite framework structure in the nanopores of which the amorphised phosphate phase is formed. The pigments effectively reduce the aluminium alloy corrosion in sodium chloride solution. The most effective pigment is obtained by mechanochemical modification of zeolite with calcium cations, followed by liquid-phase treatment with zinc nitrate and sodium phosphate. The pigments induce the formation of a protective film of zinc hydroxides on intermetallic inclusions of the alloy. The formation of phosphates is possible on the anode sections. The pigments can become promising inhibitory components of primer paints used for the protection of structures made from aluminium alloys.

The effect of additions of anticorrosive pigments on the cathodic delamination and wear resistance of an epoxy powder coating

The cathodic delamination and wear resistance of epoxy powder coatings were evaluated after adding 3 % (by wt.) of calcium ion exchanged micropigments from amorphous synthetic silica. The materials were manufactured through the innovative and economical hot mixing method, and three different coatings were considered: commercial epoxy, epoxy without micropigments submitted to the hot mixing treatment, and epoxy with micropigments. The curing kinetics of the powder coatings was studied in order to evaluate the possible effects of the micropigments on the epoxy, using differential scanning calorimetry (DSC). In addition, mechanical properties of coatings (hardness and scratch resistance) and their wear resistance (reciprocal tribometer tests) were assessed. After provoking a controlled mechanical failure in the coatings, their delamination resistance was analyzed by scanning Kelvin probe (SKP). The delamination front was calculated after adding a drop of 3.5 % NaCl solution and taking measurements for 26 days. The results show that the corrosion attack progresses through a cathodic delamination mechanism. The addition of corrosion inhibitors in epoxy powder coatings has not only allowed a considerable improvement in delamination resistance, but has also led to greater mechanical and wear resistance. At the same time, it has simultaneously reduced the chances for mechanical failure of the coating and decreased the progression rate of damage, if it occurs. The study has also been completed with electrochemical impedance spectroscopy and polarization measured of fully-immersed defective coatings in 3.5 % NaCl.

Metallurgical Dust as an Adsorbent of Heavy Metal Ions from Washing Wastewater of Electroplating Industries

The problems of wastewater treatment of electroplating industries from heavy metal ions are considered . The prospects and relevance of the sorption method of purification are shown. The results of a study on the use of dust from metallurgical industries for the extraction of hexavalent chromium, zinc, copper, nickel, and cadmium ions from the washing water of galvanic productions are presented. The possibility of intensifying the deposition of suspension particles in a settling tank, the polymer bottom of which is equipped with electromagnets, is shown. The parameters of processing the extracted sediments into anticorrosive pigments have been determined. An experimental batch of MA-25 paint was prepared on the basis of pigment from sorption purification waste. The properties of the resulting coating were investigated and it was found that it complies with all the standards imposed on this brand of paint except for color.

Physico-chemical properties of anti-corrosion pigment based on nanoporous zeolite and zinc monophosphate

Physico-chemical properties of anti-corrosion pigment based on nanoporous zeolite and zinc monophosphate

Influence of coating type, colour, and deployment timing on biofouling by native and non-native species in a marine renewable energy context

Biofouling on marine renewable energy devices presents engineering challenges for this developing sector, and has implications for the spread of marine non-native species (NNS) in coastal waters. This is particularly true at sites with abundant energy resource, little existing infrastructure, and few established NNS. Device coatings, such as antifouling paints, could reduce the risk of NNS spread. Settlement on coatings of various types and colours, representing those likely to be used on renewable energy devices, was assessed in the Orkney Islands, northern Scotland. Assemblage composition, but not overall biofouling cover, varied initially among different coloured surfaces, although differences decreased over time. Different coating types (an anticorrosive paint, a biocidal paint and a fouling-release coating) differed in biofouling abundance and composition for the full duration of the experiment. NNS were mostly, but not completely, absent from antifouling surfaces. These results can help informing antifouling strategies for the marine renewable energy industry.

Zinc Phosphate Nanoparticles: A Review on Physical, Chemical, and Biological Synthesis and their Applications.

Nanotechnology is considered one of the emerging fields of science that has influenced diverse applications, including food, biomedicine, and cosmetics. The production and usage of materials with nanoscale dimensions like nanoparticles are attractive parts of nanotechnology. Among different nanoparticles, zinc phosphate nanoparticles have attracted attention due to their biocompatibility, biosafety, non-toxicity, and environmental compatibility. These nanoparticles could be employed in various applications like anticorrosion, antibacterial, dental cement, glass ceramics, tissue engineering, and drug delivery. A variety of physical, chemical, and green synthesis methods have been used to synthesize zinc phosphate nanoparticles. All these methods have some limitations along with certain advantages. Chemical approaches may cause health risks and environmental problems due to the toxicity of hazardous chemicals used in these techniques. Moreover, physical methods require high amounts of energy as well as expensive instruments. However, biological methods are free of chemical contaminants and eco-friendly. This review is aimed to explore different methods for the synthesis of zinc phosphate nanoparticles, including physical, chemical, and more recently, biological approaches (using various sources such as plants, algae, and microorganisms). Also, it summarizes the practicable applications of zinc phosphate nanoparticles as anticorrosion pigment, dental cement, and drug delivery agents.

Improved properties of polyolefin nanocomposite coatings modified with ceria nanoparticles loaded with 2-mercaptobenzothiazole

Ceria nanoparticles (CNPs) were loaded with a corrosion inhibitor 2-Mercaptobenzothiazole (2-MBT), and used as an anticorrosive pigment. For that, the proposed additive was thoroughly mixed (1 wt%) into a Polyolefin matrix to form a nanocomposite coating that was applied on steel substrates. For comparison, non-modified polyolefin coatings, serving as reference were also prepared. Transmission-electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of the corrosion inhibitor (2-MBT) onto the CNPs. Thermal gravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) techniques confirmed ~40 wt% loading capacity of the CNPs. Electrochemical impedance spectroscopy (EIS) analysis of the coatings demonstrated higher and more durable corrosion protection efficiency of the modified polyolefin nanocomposite coatings compared to the reference coatings. The improved corrosion resistance can be attributed to a synergistic combination of corrosion inhibition due to the release of 2-MBT from CNPs and an effective distribution of the anti-corrosion pigments in the polyolefin matrix. The modified polyolefin nanocomposite coatings also demonstrate enhanced mechanical properties, 15 % higher hardness and 17 % higher erosion resistance compared to the reference coatings, due to a hardening effect conferred by the presence of CNPs loaded with 2-MBT. The improved properties of the modified polyolefin nanocomposite coatings make them attractive for industrial applications to protect steel parts.

Advances in Anti-Corrosion Polymeric and Paint Coatings on Metals: Preparation, Adhesion, Characterization and Application

Metals currently remain the main structural material used by various industries for many centuries [...]

Hollow Silica Microparticles Based on Amphiphilic Polyphosphazenes.

Hollow microparticles are important materials, offering a larger surface area and lower density than their solid counterparts. Furthermore, their inner void space can be exploited for the encapsulation and release of guest species in a variety of applications. Herein, we present phosphazene-based silica hollow microparticles prepared via a surfactant-free sol-gel process through self-assembly of the alkoxysilyl-containing polymer in water–ethanol solution. Solely, a silane-derived polyphosphazene was used as the precursor for the microparticle formation, without additional classical silica sources. These novel hollow silica-based microparticles were prepared without surfactant, using a designed amphiphilic polyphosphazene for the particle formation made by two components, a hydrophilic unit consisting of 3-mercaptopropyl(trimethoxysilane), and a hydrophobic unit (dodecanethiol) attached to the double bonds from the poly(allylamine)phosphazene backbone via a thiol-ene photoreaction. Due to these two functionalities, a “vesicle”-like self-assembled structure was formed in the reaction medium, which could be then utilized for the microparticle preparation. The influence of NaOH during the synthesis was shown to affect the size and the wall thickness of the microparticles. This effect may enhance the possibilities to tailor such microparticles for drug delivery purposes or for future controlled release of other substances, such as drugs, fragrances, or anticorrosive pigments.

Evaluation of trace-metal pollution in sediment cores from Lake Edku, Egypt

Sediments in nine short cores (<40 cm) from Lake Edku, a brackish coastal basin located east of Alexandria, Egypt, were analyzed to determine distributions of eight metals (Fe, Cd, Cr, Cu, Ni, Pb, As and Zn) and to assess the magnitude of pollution and potential biological effects. Aluminum concentrations were determined as a normalization factor. Sediments also were analyzed for texture, total carbonate, and % organic matter. Trace-metal concentrations generally increased upward in the cores, reflecting increasing influence of human activities over time. Concentrations of trace metals were strongly correlated with Fe, % clay, and % organic matter, all increased eastward across the lake. Contamination factors ranked Cd >> Pb > Cu > Zn > As > Fe > Ni > Cr. Pollution quantification methods indicated that Cd and Pb concentrations present high and moderate ecological risk for living organisms, respectively, and increased use of both elements are associated with changes in human activities over the past several decades. Contamination by Cd likely reflects the increased necessity for use of phosphate fertilizers in the watershed, and contamination by Pb may reflect its increased use in anti-corrosive paints and fuels, for example, in fishing boats. Overall, the study highlights significant anthropogenic contributions in terms of trace-metal pollution.

New out-performing structured pigments for anticorrosive practical applications

PurposeLong time ago, multistructured materials showed great interest being considered as the bridge between bulk and atomic materials. Core-shell particles are kind of composite materials that refer to multilayered structures with a core totally surrounded by shell(s) (onion-like structure). These new structures can offer an advantage of applying new adjustable parameters like shape, stoichiometry and chemical ordering, in addition to the opportunity of tailoring more complexed structures for different applications. Recently it was found that these structures can be tuned and taken for more advanced path with novel structures formed of core surrounded by multishells. The purpose of this study is to study the effect of the new anticorrosive pigments with its mutual shells and how each shell affects the performance of the pigment in protecting the metal and which shell will be more relevant in its effect.Design/methodology/approachThe prepared pigments were characterized using X-ray fluorescence, X-ray diffraction, TEM and SEM/EDX to prove their core-shell structure, and then they were integrated in coating formulations to evaluate their anticorrosive activity using immersion test and electrochemical impedance spectroscopy (EIS).FindingsThe results showed that the prepared core-shell pigments possess a lot of unique characteristics and can offer improved anticorrosive performance in the generated coatings.Originality/valueCore-mutual shells structured pigments were prepared for improving the corrosion resistivity of the organic coatings as a new trend in anticorrosive pigments.

Core/Shell Pigments with Polyaniline Shell: Optical and Physical-Technical Properties.

Core/shell pigments allow for the combination of the active anti-corrosion effect of the shell and the barrier effect of the core. This makes it possible to obtain anti-corrosion pigments, with a high—protective effect and low toxicity. Thus, the need for a comprehensive study of the properties of these pigments grows more urgent, before their application to paints and varnishes. The hiding power of core/shell pigments comes close to the one of pure polyaniline (PANi), when the PANi content in the pigment reaches 50 wt.%, with sulfuric and phosphoric acids used as dopants. This paper, also, shows that the blackness value of core/shell pigments with 10 wt.% PANi is around 35 and constant; for pure PANi, their blackness value is 40. When PANi content is 5 wt.%, kaolin-based pigment shows the lowest blackness, which happens due to a generally higher whiteness of kaolin. However, when the PANi content surpasses 10 wt.%, there seems to be no influence on the blackness of the core/shell pigments. The core/shell pigment with a 20 wt.% PANi is, optically, identical to a black-iron-oxide pigment. An increase in the PANi content of the core/shell pigment leads to an increase in the oil absorption of the samples. It was found that the dispersion process would be the most energy efficient for core/shell pigments, containing kaolin and talc as a core.

A facile method to prepare mesoporous polyaniline hollow nanosphere and its application in self-healing coating

In this work, a facile method was developed to prepare mesoporous polyaniline (mPANI) hollow nanospheres using core/shell structured silica nanospheres as substrates. The prepared mPANI hollow nanospheres were composed of external mesoporous PANI shell and internal mesoporous resorcinol-formaldehyde (RF) resin shell. The average diameter, shell thickness, specific area, average pore diameter, and total pore volume of mPANI hollow nanospheres were 330 nm, 78 nm, 75 m2 g−1, 6.9 nm, and 0.89 cm3 g−1, respectively. 1H-benzotriazole (BTAH) loading rate in mPANI hollow nanospheres was up to 35%. In addition, BTAH can be released from mPANI hollow nanospheres continuously to provide a sustained protection for epoxy coating. Epoxy coating pigmented with 2 wt% mPANI hollow nanospheres loaded with BTAH (mPANI@BTAH) presents remarkable anticorrosion property, and its coating resistance still can be maintained at 109 Ω cm2 even after 60-day immersion in 3.5 wt% NaCl solution. Furthermore, there are only slight rusts at the scratch after 30-day salt spray test, and the coating adhesion force reduced a little, still up to 6.4 MPa, indicating excellent anticorrosion property. Meanwhile, scanning vibrating electrode technique (SVET) results confirmed that epoxy coating pigmented with mPANI@BTAH hollow nanospheres exhibited obvious self-healing function. It can be concluded from the series tests that mPANI@BTAH hollow nanospheres as high performance anticorrosion pigments can strongly improve the anticorrosion performance of epoxy coating through combining the passivating function of polyaniline and corrosion inhibition of BTAH together.

Recent Progress in Synthesis and Applications of Zinc Phosphate Nanoparticles: A Review

Nowadays, nanomaterials have become the research hot topic by the virtue of their fascinating attributions in human civilization. Zinc phosphate nanoparticles (ZnPNPs), an inorganic material, possess some unique features, such as high thermal stability, low solubility in corrosive media, biocompatibility, non-toxicity and luminescence property. As a result, ZnPNPs have enormously been explored by researchers in many important applications, such as anticorrosion pigment, drug delivery, antibacterial as well as anticancer agents, biocatalyst, lubricant additives, regeneration of bone tissues and removal of toxic metal from the environmental samples, and so on. Considering diversified applications potential, morphologically different ZnPNPs have mainly been fabricated by precipitation, sonochemical and biological methods. The surface property of ZnPNPs differs with pH, temperature, reaction time, and substrate concentrations. One-step in situ and facile synthetic procedures, as well as greener synthesis protocols of ZnPNPs can be advantageous over conventional methods to eliminate toxic chemicals and by-products. In addition, both artificial and natural polymer-modified ZnPNPs would offer improved properties, such as better colloidal stability, option for further functionalization, and render desired biocompatibility of prepared hybrid nanocomposite particles in applying for targeted applications. Furthermore, both in vitro and in vivo studies of polymer functionalized ZnPNPs can be an attractive research topic in biotechnological and electrochemical fields. Therefore, the current review provides a summary of the recent progress on the fabrication methods, an opportunity for the future directions to the researchers in the improvement of shape-selective synthesis and application potentials of ZnPNPs.

Influence of Anticorrosive Pigment, Dry-Film Thickness and Conditioning Time on Protective Properties of Two-Component Epoxy Primer.

The main protective properties of two-component epoxy coating are connected by the formation of a barrier of a certain thickness between the material and aggressive, environmentally induced reactants. Anticorrosive pigment is added to the coating in order to improve its protective effects. The conditioning time refers to the time interval required for the achievement of satisfactory cohesion bonds between the coating components, as well as a satisfactory adhesion force between the coating and the base material surface. This paper presents insights obtained after experimental research into the influence of input variables (the content of anticorrosive pigment in the coating, dry-film thickness, and conditioning time) on corrosion resistance. The specimens were kept in the aggressive atmosphere of a salt-spray test chamber within time intervals of 120, 240 and 480 h, where they were cyclically sprayed with a 5% sodium chloride (NaCl) solution, and then examined in laboratory conditions. Such a procedure imitated the aggressive conditions of a service environment. After exposure in the salt-spray test chamber, the specimens were tested to determine the protective properties of the coating and to evaluate damage occurring on the coating, with the purpose of assessing the coating quality in relation to the stated input variables. At all times, when the test samples were exposed to the salt chamber atmosphere, the anti-corrosion pigment content was found to have the greatest influence with the thickness of the dry coating film. The conditioning time was an influential factor to a lesser extent, and only in some observed cases. By analyzing the interactions of the input variables and the results obtained based on mathematical models and reaction surfaces, it was possible to define the most optimal values of the input parameters. For example, after 480 h of exposure in a salt chamber, notch corrosion of 0.6 mm was observed at a dry-film thickness of D1 and an anti-corrosion pigment content of 10%.

The Performance of Antifouling Paint for Prolonged Exposure in Madura Strait, East Java Province, Indonesia

Antifouling paints are commonly utilized to minimize attached biofouling on the submerged marine structure. The evaluation of commercial both antifouling (AF) paints (Paint A and Paint B) for prolonged exposure has been investigated through field test in Suramadu Bridge, Madura strait, East Java Province, Indonesia. In addition, commercial anti-corrosion (AC) paints were also studied as a controlled coated specimen. The test panels containing all specimens of paint were exposure up to 3-months. Seawater quality parameters consisting of temperature, pH, salinity, conductivity, and dissolved oxygen (DO) were also measured during the test field. The coating properties, which consist of thickness, gloss, hardness, and adhesion strength, were carried out. It was found that both antifouling paints are remarkable to protect attached fouling organisms, but not anti-corrosion paints. Both antifouling paints' properties gradually decrease, such as adhesion strength and gloss, but not in their hardness. There were attached various fouling organisms such as barnacles, tubeworms, and brown algae, where barnacles mainly in the surface of both AC paints after exposure. Based on the result, there was no or less primary biocide of Cu2O in both AF paints where that biocide can inhibit those fouling after three months of exposure. The rapid reduction of thickness for both AF paints is maybe predominantly induced by seawater current rather than pH, salinity, and temperature.

Hydrothermal In-Situ Synthesis and Anti-Corrosion Performance of Zinc Oxide Hydroxyapatite Nanocomposite Anti-Corrosive Pigment

With the rapid development of the Chinese marine economy, the anti-corrosion of ships and marine engineering facilities has become urgent to be solved. In this paper, a stable zinc-hydroxyapatite (ZnO-HAP) nanocomposite anti-corrosive pigment was prepared by using the hydrothermal in situ synthesis technique, which supported nano-ZnO onto the hydroxyapatite (HAP) surface. The phase composition, microstructure, and performance of the ZnO-HAP nanocomposite were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), electron probe microanalysis (EPMA), and electrochemical impedance spectroscopy (EIS), and the anti-corrosion mechanism of the ZnO-HAP nanocomposite was discussed. The results show that the corrosion resistance of the ZnO-HAP/epoxy is better than that of the pure epoxy resin coating. The optimum condition to fabricate ZnO-HAP/epoxy with suitable corrosion resistance was found to be a ZnO/HAP ratio of 0.65/0.35. The synergistic complementation mechanism of ZnO and HAP enriches the metallic anti-corrosion theory and provides a new idea for the synthesis of novel and promising anti-corrosive pigments.

Optimization of Parameters for Protection of Materials by Primer Application

The protective properties of coating systems usually depend on their base layer, since its characteristics and chemical composition are greatly responsible for prevention of corrosion development. Moreover, a good primer as a base coating has to provide good adhesion between the coating system and the substrate material, as well as good cohesion, i.e., coating strength. The described experiment aimed to determine the influence of input parameters (anticorrosive pigment content, conditioning time, dry film thickness) on the adhesion properties of the coating. The optimization of input parameters was achieved by the pull-off test in order to determine their maximum values. For the purpose of imitating aggressive atmosphere of service conditions, the experiment was run in a salt spray chamber, in which samples were cyclically sprayed with 5% sodium chloride (NaCl) solution for 120 h. The obtained mathematical model makes it possible to define the optimal values of the input variables for the defined values of the required property, i.e., the adhesion properties of the applied primer for certain exploitative conditions.

Novel Development of Corrosion Resistant Paint Using Printed Circuit Board from Modern Electronic Wastes

The growth in the industrial technology and communication sectors has enhanced the usage of electronic gadgets exponentially. Thus, it becomes highly essential to find new solution to utilize or dispose these e-wastes, in order to reduce the e-waste generation. Various reports mentioned that the major component of these e-wastes is their Printed Circuit Boards. Therefore, a new ideology is proposed to use these boards to produce a new coating with good corrosion resistance. At first the boards were separated from the discarded electronic appliances and various electrical elements were separated from these boards. Then the plain circuit boards are pulverized into fine particles and mixed with paint in 3 different proportions ranging from 1:4 to 1:2. The resulting mix was applied over the steel specimen and tested for corrosion resistance. The assessment was done in the aspects of contact angle, weight loss percentage, potentio dynamic polarization technique and electro chemical impedance spectroscopy. From the results it was clear that increase in the addition of printed circuit powder content in the corrosion proof paint coating enhanced the efficiency of the corrosion resistant behaviour 3.5 times than the specimen with uncoated steel specimens. This development of corrosion resistant behaviour of printed circuit powder was attributed from the inertness offered by the presence of silicon dioxides towards the corrosive fluids. Although, the coating of 1:2 proved to be optimum to protect the steel elements from the aggressive corrosion environment, by considering the workability aspects the 1:3 combination was suggested for the innovative development of anti-corrosion paint coating from the e-waste resources.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Life cycles of every electronic wastes end with the hazardous challenging disposals&#x0D; Innovative utilizations of these electronic wastes for the corrosion resistant structural applications were detailed&#x0D; An anti corrosive coating for steel reinforcement was developed from the waste printed circuit boards&#x0D; Coating by printed circuit board powder enhanced 3.5 times more protection from the corrosion&#x0D; &#x0D; GRAPHICAL ABSTRACT