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Article
Publication date: 2 May 2017

Nivin M. Ahmed, Walaa M. Abd El-Gawad, Ahmed A. El_Shami and Eglal M.R. Souaya

This study aims to synthesize a series of new anticorrosive pigments using a new technique called “core-shell”. This technique is based on depositing thin surface layer of…

Abstract

Purpose

This study aims to synthesize a series of new anticorrosive pigments using a new technique called “core-shell”. This technique is based on depositing thin surface layer of expensive, efficient anticorrosive pigment on a cheap extender. This extender forms the bulk of the new pigments. The new pigments were constructed on cores of either waste silica fume or kaolin comprising 80-85 per cent of their chemical structure, and the ferrite shell was about of 20-15 per cent. Electrochemical studies were undertaken on two series of pigments for comparison between ferrites/silica fume and ferrites/kaolin pigment to show their performance, as the shells are different.

Design/methodology/approach

The different ferrites/silica fume and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence (XRF) and transmission electron microscopy (TEM). Immersion test and electrochemical impedance measurements were done in 3.5 per cent NaCl.

Findings

The tests revealed that paint films containing Sr ferrite/silica and Ca ferrite/kaolin were the most effective in corrosion prevention.

Practical implications

Silica fumes have a large array of uses. These pigments can be applied in various industries such as painting, wooding coating, anti-corruption coating, powder coating, architectural paint and waterproof paints. Treated kaolin can be applied in many industries besides pigment manufacture and paint formulations; it can be applied as a reinforcing filler in rubber, plastics and ceramic composites.

Originality/value

The new pigments are considered ecofriendly materials, because using them converts a waste product and a natural ore to useful marketable product, leading to reducing cost and saving the environment at the same time.

Details

Pigment & Resin Technology, vol. 46 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 13 May 2020

Essam Mossalam, Nivin M. Ahmed, Eglal M.R. Souaya and Basil El-Sabbagh

The purpose of this research is to study the physical and mechanical properties beside the durability of concrete as well as corrosion resistance of reinforced concrete by…

Abstract

Purpose

The purpose of this research is to study the physical and mechanical properties beside the durability of concrete as well as corrosion resistance of reinforced concrete by replacing Ordinary Portland cement (OPC) with different ratios of silica fume and meta-kaolin and applying two paint formulations to enhance corrosion resistance and mechanical properties. In this work, modified concrete mixes containing pozzolanic materials of industrial wastes such as silica fume (SF) with ratios ranging between (0, 10 and 15%) and calcined raw material such as meta-kaolin (MK) with ratios (0, 3, 5 and 10%), were introduced using water binder ratio (w/b) 0.45 to study their effect on the physico-mechanical properties and durability of concrete as well as corrosion protection performance of reinforced concrete. Two paint formulations containing the same ingredients except that one of them is free from talc (G1) and the other contains talc (G2) were applied on the rebars embedded in these modified mixes. Talc is known to offer high pH to the surrounding media.

Design/methodology/approach

Modified concrete mixes containing the coated reinforced concrete steel with the different paint formulations in presence and absence of talc were tested, and the corrosion behavior was studied using electrochemical impedance spectroscopy (EIS) in 3.5% NaCl, and the concrete mixes were also tested through their compressive strength, chloride permeability, scanning electron microscope/energy dispersive X-ray analysis and bond strength.

Findings

The results revealed that the hardened reinforced concrete mix containing 10% SF with 5% MK with embedded rebars coated with G2 (paint containing talc) was the best concrete system which offers concrete sustainability besides high corrosion protection performance, i.e. presence of talc in the paints combined with the effect of cement blended with SF and MK showed positive effect on the reinforced concrete properties that leads to more durability and workability.

Originality/value

The integrity of using two efficient methods of corrosion protection beside the effect of the different replacements in concrete mixes containing coated reinforced concrete steel with paint formulations free from talc (G1) and others containing talc (G2), which lead to fatal changes in the pH of the surrounding media (i.e. concrete which has high alkaline pH) to achieve good concrete properties aside with convenient paint formulations together.

Details

Pigment & Resin Technology, vol. 50 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 5 March 2018

Nivin M. Ahmed, Walaa M. Abd El-Gawad and Eglal M.R. Souaya

Core-shell is structured particles having several chemical compositions. The advantage of these particles arise from their specific design, to be used in decreasing costs…

Abstract

Purpose

Core-shell is structured particles having several chemical compositions. The advantage of these particles arise from their specific design, to be used in decreasing costs by using inexpensive material (natural ore or waste material) as carrier for thin shell of active material. This study aims to prepare ferrites/silica core-shell pigments and compare their inhibition efficiency to original ferrites. These pigments have shells of different ferrites that comprise 10-15 per cent of the prepared pigments on silica fume. Silica fume which is the core is a byproduct in the ferro–silicon industry; this core comprises 85-90 per cent of the prepared pigments.

Design/methodology/approach

The prepared core-shell pigments were characterized using transmission electron microscopy analysis, energy-dispersive X-ray analysis and sequential wavelength dispersive X-ray fluorescence. These pigments were integrated in epoxy-based paint formulations, and the physical, mechanical and corrosion properties of dry films were examined. The corrosion properties were studied by using immersion test in 3.5 per cent NaCl for 28 days.

Findings

This study showed that these new eco-friendly and inexpensive pigments are similar to ferrites in their inhibition performance, i.e. they exhibited high corrosion prevention.

Research limitations/implications

Domestic waste materials were reused in paints and only simple modification was used, and then, their effectiveness showed similar performance to that of the original pigments.

Originality/value

Ferrite and ferrite/silica pigments are environmentally friendly pigments that can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also, they can be used in industries other than paints (e.g. paper, rubber and plastics composites).

Details

Pigment & Resin Technology, vol. 47 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 18 June 2019

Walaa M. Abd El-Gawad, Nivin M. Ahmed, Mohamed M. Selim, E. Hamed and Eglal R. Souaya

In recent years, zeolites have been highlighted as a new component in many industrial applications owing to their unique properties. The purpose of this study is to apply…

Abstract

Purpose

In recent years, zeolites have been highlighted as a new component in many industrial applications owing to their unique properties. The purpose of this study is to apply three prepared types of zeolites Na-X, Na-Y and hydroxysodalite (Na-HS) in anticorrosive paint formulations to be evaluated as a partial replacement to zinc phosphate in anticorrosive paint formulations to protect carbon steel.

Design/methodology/approach

The three types of zeolites were characterized using different instrumental analysis such as X-ray diffraction, scanning electron microscopy and X-ray fluorescence. Evaluation of zeolites was done using American society for material and testing. Then, they were incorporated in paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin in the presence and absence of zinc phosphate. Their corrosion behavior was estimated using both immersion test and electrochemical impedance measurements in 3.5% NaCl.

Findings

Generally, the prepared zeolites exhibited good corrosion protection performance, but in presence of zinc phosphate the performance was better. This proves that, zeolites by themselves can resist corrosion but not efficiently, while in presence of zinc phosphate and owing to a synergistic effect between them, the performance was better. This opens the way to partial replacement of zinc phosphate with another safer and cheaper ingredient, which is zeolite.

Practical implications

The three zeolites can be applied in many industries besides the paint industry, such as reinforcing filler in rubber, plastics and ceramic composites, also can be applied in paper filling, paper coatings and electrical insulation.

Originality/value

The three zeolites are environmentally friendly materials that can partially replace other expensive anticorrosive pigments (e.g. zinc phosphate).

Details

Pigment & Resin Technology, vol. 48 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 September 2015

Nivin M Ahmed, Walaa M. Abd El-Gawad, Elham A. Youssef and Eglal R. Souaya

The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original…

Abstract

Purpose

The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original ferrites which were also prepared. Core-shell structured particles are recently gaining lots of importance due to their exciting applications in different fields; these particles are constructed from cores and shells of different chemical compositions which show ultimately distinctive properties of varied materials different from their counterparts. The new core-shell pigment is based on shell of different ferrites that comprises only 10-20 per cent of the whole pigment on kaolin (cores) which is a cheap and abundant ore that comprises 80-90 per cent of the prepared pigment. The new pigments do not only comprise two different components, but they also contain pigment and extender in the same compound; their loadings in the paint formulations ranges from 50 and 75 per cent of the whole pigment. The work showed that these eco-friendly and cheap core-shell pigments are comparable in their efficiency to that of ferrites in protecting steel substrates.

Design/methodology/approach

The different ferrites and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDAX) and transmission electron microscopy (TEM). Evaluation of these pigments was done using international standard testing methods (ASTM). After evaluation, the pigments were incorporated in solvent-based paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent NaCl for 28 days were determined.

Findings

The results of this work revealed that ferrite/kaolin core-shell pigments were close in their performance to that of the ferrite pigments in protection of steel, and at the same time, they verified good physico-mechanical properties.

Practical implications

Treated kaolin can be applied in many industries beside pigment manufacture and paint formulations; it can be applied as reinforcing filler in rubber, plastics and ceramic composites. Also, it is applied in paper filling, paper coatings and electrical insulation.

Originality/value

Ferrite and ferrite/kaolin are environmentally friendly and can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also, they can be used in industries other than paints, for example paper, rubber and plastics composites.

Details

Pigment & Resin Technology, vol. 44 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 31 December 2015

Nivin M Ahmed, Walaa M. Abd El-Gawad and Eglal R. Souaya

The purpose of this study is to prepare core-shell ferrites/kaolin pigments and compare their efficiency in protecting metal substrates to original ferrites. The new…

Abstract

Purpose

The purpose of this study is to prepare core-shell ferrites/kaolin pigments and compare their efficiency in protecting metal substrates to original ferrites. The new pigments are based on precipitating a shell of different ferrites that comprise only 10-20 per cent of the whole pigment on kaolin (core), which is a cheap and abundant ore comprising 80-90 per cent of the prepared pigment. These new pigments combine the properties of both its core and shell counter-parts, exhibiting improved corrosion protection properties. Furthermore, the pigments are represented as efficient, economically feasible and eco-friendly with comparable efficiency to that of original ferrites in protecting steel substrates.

Design/methodology/approach

The new pigments were characterized using different analytical and spectrophotometric techniques, e.g. transmission electron microscopy, energy-dispersive X-ray analysis and X-ray fluorescence. The pigments were then incorporated in epoxy-based paint formulations. The physico-mechanical properties of dry films and their corrosion properties were tested using accelerated laboratory tests in 3.5 per cent NaCl for 28 days.

Findings

The results of this study revealed that ferrite/kaolin core-shell pigments performance was almost close to that of the ferrite pigments in the protection of steel, and, at the same time, they confirmed good physico-mechanical properties.

Practical implications

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

Originality/value

Ferrite and ferrite/kaolin are environmentally friendly pigments, and they can impart high anticorrosive behavior to paint films with concomitant cost savings.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 July 2014

Nivin M. Ahmed, Walaa M. Abd El-Gawad, Elham A. Youssef and Eglal M. Souaya

The purpose of this work is to prepare new core-shell pigments based on silca fume waste as core and ferrite pigments in the shell. Silica fume is a byproduct of the…

Abstract

Purpose

The purpose of this work is to prepare new core-shell pigments based on silca fume waste as core and ferrite pigments in the shell. Silica fume is a byproduct of the smelting process in the ferrosilicon industry. The reduction of high-purity quartz to silicon at temperatures up to 2,000°C produces SiO2 vapours which then oxidize and condense at low-temperature zones to tonnage amounts of tiny particles consisting of non-crystalline silica that is collected and sold rather than being land-filled because nowadays there is increasing environmental concern with regard to excessive volumes of solid waste hazards accumulation. Silica has no direct effect in protecting metals from corrosion, but on precipitating an effective anticorrosive pigment like ferrite on its surface with low concentrations, this can bring out new core-shell pigment with good anticorrosive performance and low cost. The new pigments will be constructed on a waste silica fume core comprising 80-85 per cent of its chemical structure and the ferrite shell that will be only about 20-15 per cent. These pigments are represented as efficient, economically feasible and eco-friendly.

Design/methodology/approach

The different ferrites and ferrites/SiO2 pigments were characterized using different analytical and spectro-photometric techniques, such as X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray and transmission electron microscopy (TEM). Evaluation of these pigments was done using international standard testing methods american standard testing methods (ASTM). After evaluation, the pigments were incorporated in solvent-based paint formulations based on medium oil-modified soya-bean-dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent sodium chloride for 28 days were determined.

Findings

The results of this work revealed that ferrite/SiO2 core-shell pigments were close in their performance to that of the ferrite pigments in protection of steel, and at the same time, they verified good physico-mechanical properties.

Practical implications

As silica fume has a large array of uses, these pigments can be applied in various industries such as painting, wooding coating, anti-corruption coating, powder coating, architectural paint and waterproof paints.

Originality/value

Ferrite, ferrite/SiO2 are environmentally friendly pigments which can impart high anticorrosive behaviour to paint films with concomitant cost savings.

Details

Pigment & Resin Technology, vol. 43 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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