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1 – 10 of over 1000H. Abd El-Wahab, A.M. Hassan, A.M. Naser, O.A. Fouad, A.M. El-Din and O.A.G. Wahba
The purpose of this paper was to prepare and evaluate a nanosized mixed calcium iron oxide as a high heat-resistant pigment. Heat-resistant pigments can be defined as chemical…
Abstract
Purpose
The purpose of this paper was to prepare and evaluate a nanosized mixed calcium iron oxide as a high heat-resistant pigment. Heat-resistant pigments can be defined as chemical substances that impart color to a substrate or binder and retain their color and finish at elevated temperatures. Mixed metal oxides have been widely used as pigments in coating formulations.
Design/methodology/approach
This work presents synthesis of nanosized calcium iron oxide as an inorganic pigment by using simple synthesis technique, namely, solid-state calcination method, to study its heat and corrosion resistance. The prepared pigment was characterized by using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and inductive coupling plasma. It was incorporated into paint formulations, and the heat, corrosion and mechanical resistance of dry paint film was evaluated.
Findings
In this work, the prepared calcium iron oxide pigment showed excellent heat and corrosion resistance.
Research limitations/implications
Heat-resistant coatings are required for industrial applications, mainly for reactors, exhaust pipes, space craft, stacks and similar equipments that are permanently and occasionally exposed to elevated temperatures. It was previously quite difficult to formulate heat-resistant organic coatings because of binder deficiencies; new vehicles for such applications are now available. Thus, the development of silicon resins has markedly advanced the utility of heat-resistant paints. High-temperature pigments are inorganic chemical compounds that impart and retain their color and finish to a substrate or binder at elevated temperatures.
Practical implications
The nanosized mixed calcium iron oxide could be used as a pigment in paint formulations. It was found that it significantly enhances the heat, corrosion and mechanical resistance. It can also find numerous applications in other paint formulations for surface coating.
Originality/value
The paper shows how the pigment consisting nanosized mixed calcium iron oxide could be used in heat-resistant paint formulations for coating metal surfaces.
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The purpose of this paper is to synthesize MeO‐type pigments, focusing on the oxides containing zinc and magnesium.
Abstract
Purpose
The purpose of this paper is to synthesize MeO‐type pigments, focusing on the oxides containing zinc and magnesium.
Design/methodology/approach
Oxides ZnO and MgO were synthesized, their morphology was evaluated, and their impact on the physical properties of the paint film were assessed. A pigment of ZnO/core‐shell type also was synthesized. The physical‐chemical property of the synthesized pigments and the anticorrosion efficiencies of the paint films pigmented by them were determined. The binder used in the researched coatings was epoxy‐ester resin.
Findings
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 epoxyester coating.
Practical implications
The synthesized pigments can be used conveniently in coatings protecting metal substrates against corrosion.
Originality/value
Of benefit is the fact that the synthesized pigments do not contain any environmentally harmful substances.
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Osama A. G. Wahba, Ali M. Hassan, H. Abd El-wahab, A. Mohy-Eldin, A.M. Naser and Osama A. Fouad
The purpose of this paper is to investigate the synthesis of calcium-based group of mixed metal oxide (MMO) pigments. The evaluation of these pigments as heat and corrosion…
Abstract
Purpose
The purpose of this paper is to investigate the synthesis of calcium-based group of mixed metal oxide (MMO) pigments. The evaluation of these pigments as heat and corrosion resistant was also explored.
Design/methodology/approach
Two simple synthesis techniques, namely, co-precipitation and solid-state calcination method, were used to synthesise nanosized MMO pigments. And then the physico-chemical requirements according to standards for the synthesised pigments are investigated.
Findings
The prepared MMO pigments were mainly in the single phase double oxide forms. The prepared oxides exhibited good heat (up to 600°C) and corrosion resistance properties (in 5 per cent NaCl for 500 h).
Research limitations/implications
This paper investigates the physico-chemical properties of synthesised calcium-based group of MMO pigments. And then evaluate it as heat and corrosion resistant paints. The simple techniques used for synthesis of nanosized MMO pigments will significantly improve the research and development of pigments’ structure and performance.
Practical implications
Calcium-based MMO pigments can be used as heat and corrosion resistant pigments. The easy synthesis of the mixed oxide pigments will open the door for further vital special industrial uses and applications.
Originality/value
Low cost, simple techniques and using naturally abundant material can be used for mass production of some other low-cost nanosized materials.
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Silicone resin based protective coatings are generally used for high temperature applications. In this work, anti‐corrosive and heat resistant properties of titanium dioxide…
Abstract
Silicone resin based protective coatings are generally used for high temperature applications. In this work, anti‐corrosive and heat resistant properties of titanium dioxide, mica, zirconium oxide and quartz combination pigments with silicone resin as carrier vehicle in primer and top coat for mild steel surface have been evaluated. Promising results were obtained, showing that the ceramic pigments (zirconium oxide and quartz) impart heat‐resistance protection for steel substrate up to 370°. Electro‐chemical impedance spectroscopy, immersion studies and salt spray test results show good corrosion protection for the steel surface.
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The paper deals with the study of modified phosphate compounds and their anticorrosion action when incorporated in paints. The pigments commence as zinc orthophosphate, the…
Abstract
The paper deals with the study of modified phosphate compounds and their anticorrosion action when incorporated in paints. The pigments commence as zinc orthophosphate, the modification of which can give phosphosilicates, phosphomolybdates, or basic phosphates. With respect to cations, the combination of zinc with calcium, strontium, barium, or aluminium, is possible. The modified anticorrosive pigments differ in their water solubility, inhibition efficiency of the aqueous extracts, and anticorrosion action, when incorporated in organic coatings. Nine types of modified phosphates were studied. The effect in coatings of organic inhibitor in the presence of anticorrosive inorganic pigments was determined.
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Abstract
Purpose
The purpose of this paper is to enhance the anticorrosion property of aluminium pigments and to improve their compatibility with polymers in coating.
Design/methodology/approach
Aluminium pigments encapsulated by organic‐inorganic layer were prepared by hydrolysis and condensation of organic silane acrylate resin and tetraethoxy silane (TEOS) on the surface of pigments via sol‐gel method. TEOS and poly (methyl methacryalte‐n‐butyl acrylate‐vinyl triethoxysilane) (PMBV) formed in advance by co‐polymerisation of methyl methacrylate (MMA), n‐butyl acrylate (BA) and vinyl triethoxysilane (VTES) were used as precursors. The adhesion property of the aluminium pigments was measured by peel test, and the loss of silvery appearance after encapsulation and acid soaking were both evaluated by colour lightness difference (ΔL) measurement. The encapsulated aluminium pigments were further characterised by means of FTIR, SEM, TG and XPS.
Findings
It was found that PMBV‐SiO2 thin films could be formed on the surface of aluminium pigments smoothly and uniformly, and the adhesion and anticorrosion performances of encapsulated aluminium pigments were improved significantly.
Research limitations/implications
The organic silane acrylate resin used as a precursor in the sol‐gel process could be synthesised from other aclyate monomers. In addition, the hydrolysis and condensation mechanism of organic silane acrylate resin on the surface of aluminium pigments need further studies.
Practical implications
The method developed provided a good solution to the two problems of aluminium pigments and increased their application values.
Originality/value
The method of improving adhesion and anticorrosion properties of aluminium pigments was novel and could find numerous applications in surface coatings and adhesives.
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Osama A.G. Wahba, Ali M. Hassan, Abdelrahman M. Naser and Adel M.G. Hanafi
The purpose of this study to investigate the synthesis of new Cr(III), Fe(III), Ni(II) and Cu(II) Schiff base complexes by a simple technique (microwave technique). The evaluation…
Abstract
Purpose
The purpose of this study to investigate the synthesis of new Cr(III), Fe(III), Ni(II) and Cu(II) Schiff base complexes by a simple technique (microwave technique). The evaluation of the prepared complexes as pigments as corrosion resistant was also explored.
Design/methodology/approach
The Schiff base complexes were prepared by using microwave method (green chemistry), and then, the physico-chemical requirements according to standards for the synthesised pigments were investigate.
Findings
The prepared complexes exhibit good physical, mechanical and corrosion properties as pigments in paint formulations.
Research limitations/implications
The simple technique used for synthesis of metal complex pigments will significantly increase the cost saving for the manufacturing of such pigments category. Also, the used technique is considered a green method (eco-friendly), as there no organic solvent was used.
Practical implications
The evaluation of the prepared complex pigments as corrosion resistants was also studied.
Originality/value
It is a simple technique, green synthesis (no solvent used) is involved and high yield is obtained.
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N. Kouloumbi, P. Pantazopoulou and P. Moundoulas
The objective of this work was to examine the anticorrosive behaviour of four different epoxy coatings, which were formulated with zinc pigments and were applied on pretreated…
Abstract
The objective of this work was to examine the anticorrosive behaviour of four different epoxy coatings, which were formulated with zinc pigments and were applied on pretreated steel panels exposed to deionised/deaerated water taken from the installations of the Greek Public Electricity Company, as well as to compare the results of this study with those of a relevant, previous work. The coating's performance was assessed by the measurement of the potentiodynamic polarisation resistance, by electrochemical impedance spectroscopy and the measurement of dielectric permittivity, during the deionised/deaerated water immersion tests. Additionally, accelerated salt spray tests were performed. All types of coatings tested exhibited a high protective performance. It was concluded that the epoxy system containing zinc dust was the most effective anticorrosion coating under the conditions relevant to this study.
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Liliya Frolova and Tatyana Butyrina
The purpose of this paper is to study the patterns of formation of anti-corrosion properties, the development of compositions for pigments by using the method of co-precipitation…
Abstract
Purpose
The purpose of this paper is to study the patterns of formation of anti-corrosion properties, the development of compositions for pigments by using the method of co-precipitation and subsequent heat treatment.
Design/methodology/approach
To obtain co-precipitated hydroxides, aqueous solutions of salts were used. The conditions of synthesis varied according to the following parameters: the nature of the starting salts of metals; and the ratio of metal cations. The anticorrosive activity of the pigments was evaluated by the potentiodynamic method, by comparing the anodic and cathodic polarization curves, and calculated potentials and corrosion currents on the basis of regions of Tafel on curves. Polarization curves were obtained by using Potentiostat/Galvanostat/ZRA Gamry, which connected to the PC, and by using the program Gamry Framework. The measurement results were processed by using the method of simplex-lattice planning. X-ray diffractograms of pigments were recorded on a DRON – 2.0 diffractometer (monochromatic copper radiation with a nickel filter).
Findings
The paper deals with the results of research the dependence of colour characteristics and anticorrosion properties of synthesized compositions on their nature and composition. The presence of aluminium cations leads to the formation of solid solutions of ferrum and aluminium oxyhydroxides.
Originality/value
The main technological properties of pigments are determined by the anionic and cationic composition. Colour characteristics are determined by the cation-chromophore. The anti-corrosive properties of non-calcined pigments are determined to a greater extent by the presence of the formed hydroxyl ions and the composition of the compounds. The greatest protective effect is observed when using double compounds of metals, the dissociation constants of which differ significantly. The protective effect is mainly determined by the slowdown of the anode process. Anions containing aluminium atoms accelerate the corrosion processes.
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