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This paper seeks to synthesize needle‐shaped anticorrosion pigments based on the ferrites of Zn, Ca and Mg for metal protecting paints.

Anticorrosion pigments were synthesized from oxides or carbonates at hot temperatures. The following pigments were synthesized: ZnFe₂O₄, MgFe₂O₄, CaFe₂O₄, Mg_0.2Zn_0.8Fe₂O₄, and Ca_0.2Zn_0.8Fe₂O₄. The prepared pigments were characterized by means of X‐ray diffraction analysis, by measuring the distribution of particle size and by means of scanning electron microscopy. The synthesized anticorrosion pigments were used to formulate epoxy coatings with PVC = 10 per cent for the synthesized pigment and with the PVC/CPVC ratio = 0.3. The coatings were tested for physical‐mechanical properties and in corrosion atmospheres. The corrosion test results were compared with aluminium zinc phosphomolybdate.

The needle‐shaped particles were identified in the formulated pigments. It was found that all of the synthesized pigments had high anticorrosion efficiency comparable with that of Zn‐Al phosphomolybdate. The needle‐shaped particles markedly contributed to the advancement of the physical‐mechanical properties of epoxy coatings.

The synthesized pigments can be conveniently used in coatings protecting metal bases against corrosion.

The application of the synthesized pigments with the needle‐shaped particles in anticorrosion paints protecting metals presents a new method. The benefit of the application and method of synthesizing anticorrosion pigments is that they do not contain heavy metals and are acceptable for the environment.

The purpose of this paper is to report the electrochemical verification of anticorrosive properties of NiZn ferrites as pigments in protective coatings and evaluation of their microwave absorbing properties.

Ferrites, represented by formula Ni_xZn_(1−x)Fe₂O₄, where x=0, 0.2, 0.4, 0.6, 0.8, 1.0, were synthesized using a ceramic method. The samples of ferrites were examined by X‐ray diffraction and SEM. Immersion tests in ferrite extracts, combined with electrochemical tests using techniques such as polarization curves, linear polarization and electrochemical impedance spectroscopy (EIS) were involved to determine the protective action provided by the ferrites. Epoxy coatings containing 10 vol.% of the ferrite were investigated using EIS. Experimental verification is provided of the microwave attenuation capability of coatings containing the investigated ferrites. Reflection loss, measured in the frequency range of 6.5‐15 GHz, exhibited maximum attenuation at a level of 8‐16 dB.

The results obtained suggest that NiZn ferrites possess active anticorrosive properties and support inhibition of the cathodic reaction by scale deposition at the metal substrate in an alkaline environment created by the pigments and the cathodic reaction. Additionally, they can serve as a microwave suppressor.

NiZn pigments can be used in coatings to serve simultaneously as an active anticorrosion, non‐toxic pigment and a material protecting against electromagnetic interference problems.

The paper provides information regarding the anticorrosive properties of NiZn ferrites as pigments for protective coatings and also microwave absorbing materials. An attempt was made to elucidate the potential mechanism of anticorrosive action of these pigments.

The purpose of this paper is to synthesize the manganese ferrite nanoparticle MnFe₂O₄ and to investigate the structure, size and to study the electronic and the magnetic properties of MnFe₂O₄ nanoparticles.

The co-precipitation method is used to synthesize the MnFe₂O₄. The structure and size were investigated by X-ray diffraction. The superconducting quantum interference device is used to determine the some magnetic ground. From theoretical investigation point of view self-consistent ab initio calculations, based on density functional theory approach using full potential linear augmented plane wave method, were performed to investigate both electronic and magnetic properties of the MnFe₂O₄. The high temperatures series expansion (HTSE) is used to study the magnetic properties of MnFe₂O₄.

The saturation magnetization, the coercivity and the transition temperature varied between 21-43 emu/g, 20-50 Oe and 571-630 K, respectively, have been studied. The gap energy of MnFe₂O₄ has been deduced. The critical temperature and the critical exponent have been obtained using HTSEs.

In the present work, the authors study the electronic and magnetic properties of MnFe₂O₄. The results obtained by the experiment and by ab initio calculations were used in HTSE as input to deduce other physical parameters.

The development of new protective organic coatings is affected by a number of factors, the most important ones at present being those related to environmental acceptability of anticorrosive pigments. An effective solution has been shown to be the application of anticorrosive inorganic pigments based on mixed metal oxides. These pigments consist of spinel and rutile lattice structures. In order to examine the anticorrosive properties, the individual pigments prepared were added to alkyd and styrene‐acrylate based test coatings. Both the anticorrosion efficiencies, and the mechanisms of action of the pigments were also evaluated.

This paper aims to investigate the electrocatalytic activity of CoFe_1.9Mo_0.1O₄-Ce_0.8Gd_0.18Ca_0.02O_2-δ composite (CFMo-CGDC) for the direct synthesis of ammonia from H₂O and N₂ under atmospheric pressure.

CoFe_1.9Mo_0.1O₄ nanoparticles (CFMo NPs) were synthesized via a sol-gel method. CFMo NPs were characterized using X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET) specific surface area measurement and scanning electron microscope (SEM). Double-chamber reactor was used to synthesize ammonia using H₂O and N₂ as precursors. The factors affecting the ammonia formation rate (applied voltage and temperature) were studied.

CoFe_1.9Mo_0.1O₄ nanoparticles (CFMo NPs) were synthesized via a sol-gel method. CFMo NPs were characterized using XRD, Brunauer–Emmet–Teller (BET) specific surface area measurement and SEM. Double-chamber reactor was used to synthesize ammonia using H₂O and N₂ as precursors. The factors affecting the ammonia formation rate (applied voltage and temperature) were studied.

The usage of CFMo-CGDC composite as an electrocatalyst for the synthesis of ammonia directly from H₂O and N₂.

This paper aims to study the various developments taking place in the field of gas sensors made from polyaniline (PANI) nanocomposites, which leads to the development of high-performance electrical and gas sensing materials operating at room temperature.

PANI/ferrite nanocomposites exhibit good electrical properties with lower dielectric losses. There are numerous reports on PANI and ferrite nanomaterial-based gas sensors which have good sensing response, feasible to operate at room temperature, requires less power and cost-effective.

This paper provides an overview of electrical and gas sensing properties of PANI/ferrite nanocomposites having improved selectivity, long-term stability and other sensing performance of sensors at room temperature.

The main purpose of this review paper is to focus on PANI/ferrite nanocomposite-based gas sensors operating at room temperature.

The purpose of this paper is to search for toxic anticorrosive pigments’ substitute in protective coatings is one of the important tasks that the specialists in the field of steel corrosion face.

One of the ways to solve the problem of metal corrosion is to use complex oxides as pigments, which are characterized as low-toxic compounds and possess the ability to inhibit corrosion.

In the production of ferrites, it is possible to use production waste as raw material, and that makes it possible to reduce the price of the resulting product and solve environmental problems simultaneously.

Permanent growth of world production is accompanied by the increasing environment corrosiveness, associated with the intensification of air, water basin and soil pollution by industrial waste. This, as well as the continuously increasing operated metal stock, has recently made the tendency of metals’ total loss from corrosion steadily increasing. All of this points to the importance of studying corrosion processes and the systematic and effective fight against metal corrosion.

The purpose of this paper is to synthesize anticorrosion pigments ZnFe₂O₄ from diverse raw materials of various shapes and size of primary particles.

Anticorrosion pigments were synthesized through a high‐temperature process during a solid phase. Zinc ferrites were prepared from hematite (α‐Fe₂O₃), goethite (α‐FeO.OH), magnetite (Fe₃O₄), and specularite (Fe₂O₃) entering into reaction with zinc oxide at temperatures ranging from 600 up to 1,100°C. The nature of the initial raw material, primarily the shape of its particles, affects the shape of the particles of the synthesized zinc ferrite. The formulated zinc ferrites had a rod‐shape, lamellar, and/or isometric shape. The shape of the particles of synthesized zinc ferrites was studied with regard to its effects on the mechanical and corrosion resistance of organic coatings. The obtained pigments were characterized by means of X‐ray diffraction analysis and scanning electron microscopy. The synthesized anticorrosion pigments were used to prepare epoxy coatings and water‐borne styrene‐acrylate coatings that were subjected to post‐application tests for physical‐mechanical properties and anticorrosion properties.

The shape of the particles was identified in the synthesized pigments. X‐ray diffraction analysis revealed the degree of precipitation and lattice parameters. All of the synthesized pigments had good anticorrosion efficiency in an epoxy and in styrene‐acrylate coatings. Compared with a commercially used anticorrosion pigment, their protective power in coatings was demonstrably stronger.

The synthesized pigments can be used conveniently in coatings protecting metal bases against corrosion.

The synthesis of zinc ferrites with different particle shapes for applications in anticorrosion coatings provides a new way of protecting metals against corrosion. Of benefit is the fact that the synthesized pigments do not contain any environmentally harmful substances.

This study aims to explore the possibility of using magnetic biochar composite (MBCC) derived from Heglig tree bark (HTB) powder (agricultural solid waste) and cobalt ferrite (CoFe₂O₄, CFO) for oil spill removal from seawater surface.

One-pot co-precipitation route was used to synthesize MBCC. The prepared materials were characterized by X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy. The densities of the prepared materials were also estimated. Crude, diesel engine and gasoline engine oils were used as seawater pollutant models. The gravimetric oil removal (GOR) method was used for removing oil spills from seawater using MBCC as a sorbent material.

The obtained results revealed that the prepared materials (CFO and MBCC) were able to remove the crude oil and its derivatives from the seawater surface. Besides, when the absorbent amount was 0.01 g, the highest GOR values for crude oil (31.96 ± 1.02 g/g) and diesel engine oil (14.83 ± 0.83 g/g) were obtained using MBCC as an absorbent. For gasoline engine oil, the highest GOR (27.84 ± 0.46 g/g) was attained when CFO was used as an absorbent.

Oil spill removal using MBCC derived from cobalt ferrite and HTB. Using tree bark as biomass (eco-friendly, readily available and low-cost) for magnetic biochar preparation also is a promising method for minimizing agricultural solid wastes (e.g. HTB) and obtaining value-added-products.

The purpose of this paper is to determine a new easy route to obtain high performance and economic anticorrosive hybrid pigments based on kaolin and ferrite. The new route is based on depositing a surface layer of an expensive efficient anticorrosive pigment (ferrite) on a bulk of cheap extender pigment (kaolin). The combination of these pigments can add improved properties to the new pigment different from each of its individual components. These improved properties lead to imparting new properties to paint films containing these prepared pigments.

The new prepared hybrid pigments contain different concentrations of deposited ferrite on kaolin surface, are determined using X‐ray fluorescence analysis to estimate the concentration of each element in the pigments. The pigments are characterised using different spectro‐photometric and analytical methods to prove the deposition of the shell layer and elucidate the structure of their particles. Then, they are incorporated in anticorrosive paint formulations, where their presence in these formulations is between 50 and 75 per cent of the total pigments in the paint formula. A model of the mechanism of protection to the metal substrate is presented.

The results show that the presence of these hybrid pigments imparts excellent corrosion protection to steel substrates, in spite of their different concentrations and loadings in the paint films.

These pigments can be applied in other polymer composites, e.g. rubber and plastics as filler and reinforcing agent.

Prepared pigments are eco‐friendly and can replace other hazardous pigments (e.g. chromates) – also it can replace original ferrite pigments. These pigments can compensate for the presence of other known pigments in markets successfully. The main advantage of these pigments is that they combine both the properties of their counter‐parts, and they are of lower cost than the original inhibitive pigment (ferrite). Also, they can be applied in other industries other than paints, e.g. paper, rubber and plastics composites.