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Article
Publication date: 1 December 2005

Nivin M. Ahmed, Adel Attia and Mohamed M. Selim

Aims to study inhibitive properties of new compounds that are based on the Wurtzite structure of zinc oxide with an admixture of cobalt using zinc oxide as a reference.

Abstract

Purpose

Aims to study inhibitive properties of new compounds that are based on the Wurtzite structure of zinc oxide with an admixture of cobalt using zinc oxide as a reference.

Design/methodology/approach

The conditions for the preparation of pigments using different ratios of both cobalt and zinc were investigated. Characterization of these pigments was carried out using spectroscopic methods of analysis via X‐ray diffraction, transmission and scanning electron microscopy. Also, evaluations of the pigments prepared, in terms of oil absorption, specific gravity, water‐soluble matter and pH, using international standard testing methods was performed. The pigments prepared were incorporated in anticorrosive paint formulations based on medium oil alkyd resin as a binder. The physico‐mechanical properties of the relevant paint films were obtained, while their anticorrosive properties were assessed by tests in 3.5 percent NaCl solution for 28 days. Electrochemical measurements based on corrosion rates of paint films also were studied.

Findings

The results showed that the anticorrosive protection properties of the pigment prepared were better than with zinc oxide pigment alone.

Research limitations/implications

The pigments prepared can be used as reinforcing filler in different rubber and plastic composites providing them with an intense green color. As the concentration of cobalt oxide exceeds 15 percent, the reinforcing and effects decreased and vice versa.

Originality/value

Zinc chromate is one of the anticorrosive pigments most frequently used in the formulation of primers. However, its environmental aggressiveness and toxicity severely restrict its use and different green alternatives have been proposed in order to replace it. One such alternative is the pigment evaluated in this paper. New pigment applications, such as reinforcing fillers for rubber and plastic composites, also could be attractive.

Details

Anti-Corrosion Methods and Materials, vol. 52 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 August 1964

In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are…

Abstract

In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are generally classified according to the base or pigment which actively prevents corrosion—e.g. metallic zinc in zinc/epoxy formulations— or by the base which produces a barrier action against corrosion, e.g. bitumen in bituminous paints. Exceptions to this are the etching primers, which are separately classified. About 300 primers are described, the manufacturers' names and addresses being cross‐indexed and listed separately on page 48.

Details

Anti-Corrosion Methods and Materials, vol. 11 no. 8
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 7 November 2008

Nivin M. Ahmed

The purpose of this paper is to present a new trend of anticorrosive pigments based on bulk (core) of zinc oxide covered with a surface layer of phosphates.

Abstract

Purpose

The purpose of this paper is to present a new trend of anticorrosive pigments based on bulk (core) of zinc oxide covered with a surface layer of phosphates.

Design/methodology/approach

A new batch of pigments based on core‐shell theory containing a core (bulk) of cheap oxides covered by a layer of phosphates were prepared. These new pigments combined the properties of both components besides being more economically feasible. Simple chemical techniques were used to prepare these pigments. Characterization of these pigments using X‐ray diffraction and scanning electron microscopy was carried out. Evaluation of these pigments using international standard testing methods was estimated. These pigments were incorporated in solvent‐based paint formulations based on medium oil alkyd resin. The physico‐mechanical properties of dry films and their corrosion properties using an accelerated laboratory test in 3.5 percent NaCl for 28 days were tested.

Findings

It was found that those pigments based essentially on zinc oxide covered with a surface layer of phosphates were easily prepared, are economically feasible and can successfully replace original phosphates with similar efficiency in their corrosion protection behaviour.

Practical implications

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

Originality/value

The prepared pigments 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, e.g. paper, rubber and plastics composites.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 April 1990

F. Sjoukes

In the hot dip galvanizing process two different fluxes are used to remove the zinc oxide layer, always present on the liquid zinc surface. When this oxide layer, which…

Abstract

In the hot dip galvanizing process two different fluxes are used to remove the zinc oxide layer, always present on the liquid zinc surface. When this oxide layer, which contains also aluminium oxide, is dragged into the zinc by the articles, interfering the reaction zinc‐iron. In former days a flux floating on a part of the liquid zinc surface was rather common, at present this wet flux is almost completely replaced by the dry galvanizing process. Since the chemical reactions taking place in the wet flux, partly take place in the flux for dry galvanizing too, first this wet flux will be discussed in brief.

Details

Anti-Corrosion Methods and Materials, vol. 37 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 October 2014

V. Rajasekharan and P. Manisankar

The purpose of this study is to introduce mechanochemically prepared polyaniline anticorrosive additives. In primer coating technology, there is an increasing interest in…

Abstract

Purpose

The purpose of this study is to introduce mechanochemically prepared polyaniline anticorrosive additives. In primer coating technology, there is an increasing interest in the development of efficient anticorrosive additives which replace the conventional inorganic anticorrosive pigments like heavy metal chromates and phosphates normally added to primer paints for the coating on metals. Conducting polymers are found to be better alternatives.

Design/methodology/approach

Polyaniline phosphate is synthesized through solid-state conditions without using any solvent. The synthesized polyaniline phosphate is added in the primer formulation instead of zinc phosphate. Primers with different quantity of zinc phosphate are also formulated and studied for comparison. The comparison between their abilities to control corrosion of carbon steel were done with application of open-circuit potential monitoring, polarization and electrochemical impedance spectroscopy methods in 3.5 per cent NaCl solution.

Findings

Corrosion studies indicate that polyaniline phosphate can improve corrosion protection properties by taking part the passivation processes. The performance of polyaniline phosphate is better than zinc phosphate.

Originality/value

I certify that the results are from our original research and this paper is neither considered for publication elsewhere nor published previously.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 27 June 2008

A. Kalendová and D. Veselý

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

Abstract

Purpose

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

Design/methodology/approach

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.

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 epoxy and in styrene‐acrylate coatings. Compared with a commercially used anticorrosion pigment, their protective power in coatings was demonstrably stronger.

Practical implications

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

Originality/value

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.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 6 May 2020

Anh Thi Le and Swee-Yong Pung

This paper aims to investigate the reusability of metal/metal oxide-coupled ZnO nanorods (ZnO NRs) to degrade rhodamine B (RhB).

Abstract

Purpose

This paper aims to investigate the reusability of metal/metal oxide-coupled ZnO nanorods (ZnO NRs) to degrade rhodamine B (RhB).

Design/methodology/approach

ZnO NRs particles were synthesized by precipitation method and used to remove various types of metal ions such as Cu2+, Ag+, Mn2+, Ni2+, Pb2+, Cd2+ and Cr2+ ions under UV illumination. The metal/metal oxide-coupled ZnO NRs were characterized by scanning electron microscope, X-ray diffraction and UV-Vis diffuse reflectance. The photodegradation of RhB dye by these metal/metal oxide-coupled ZnO NRs under UV exposure was assessed.

Findings

The metal/metal oxide-coupled ZnO NRs were successfully reused to remove RhB dye in which more than >90% of RhB dye was degraded under UV exposure. Furthermore, the coupling of Ag, CuO, MnO2, Cd and Ni particles onto the surface of ZnO NRs even enhanced the degradation of dye. The dominant reactive species involved in the degradation of RhB dye were OH- and O2-free radicals.

Research limitations/implications

The coupling of metal/metal oxide onto the surface of ZnO NRs after metal ions removal could affect the photocatalytic performance of ZnO NRs in the degradation of organic pollutants in subsequent stage.

Practical implications

A good reusability performance of metal/metal oxide-coupled ZnO NRs make ZnO NRs become a desirable photocatalyst material for the treatment of wastewater, which consists of both heavy metal ions and organic dyes.

Originality/value

Metal/metal oxide coupling onto the surface of ZnO NRs particles improved subsequent UV-assisted photocatalytic degradation of RhB dye.

Details

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

Keywords

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Article
Publication date: 1 June 1982

E.S. Lower

Zinc stearate (Zinc distearate) is a fine white soft and muctuous odourless bulky powder, molecular weight 632. Its outstanding characteristic is the extremely small…

Abstract

Zinc stearate (Zinc distearate) is a fine white soft and muctuous odourless bulky powder, molecular weight 632. Its outstanding characteristic is the extremely small particle size of the top quality material, which can be less than one micron in diameter, giving it a high specific surface e.g. the order of 25,000 sq.cm. per gram.

Details

Pigment & Resin Technology, vol. 11 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 December 1988

Eric Carter

The need for environmentally acceptable anti‐corrosive pigments to replace those based on lead and chromates in priming paints has stimulated the emergence of phosphate…

Abstract

The need for environmentally acceptable anti‐corrosive pigments to replace those based on lead and chromates in priming paints has stimulated the emergence of phosphate, molybdate and borate types and many others. However there are widespread doubts about the ability of these “non‐toxic” alternatives to provide the same degree of corrosion‐resistance as the lead and chrome pigments. This has encouraged a search for ways and means of boosting the inhibitive action of the newer pigments, for instance by mixing with other ingredients that might promote a synergistic effect. There has been a growing interest in utilising inert “barrier” pigments for this purpose and the development of synthetic iron oxide with a flake‐like crystalline structure is a significant step forward in this context.

Details

Pigment & Resin Technology, vol. 17 no. 12
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 November 2016

Guosheng Huang, Xiangbo Li and Lukuo Xing

This paper aims to examine the performance of low-pressure cold-sprayed zinc–nickel (Zn-Ni) composites coating, i.e. whether it has the same performance as Zn-Ni alloy coating.

Abstract

Purpose

This paper aims to examine the performance of low-pressure cold-sprayed zinc–nickel (Zn-Ni) composites coating, i.e. whether it has the same performance as Zn-Ni alloy coating.

Design/methodology/approach

In this paper, Zn-Ni composites coatings containing four different nickel contents were prepared with commercial DYMET 413 low-pressure cold spraying system under the same parameters. Corrosion behaviors of four kinds of coatings were examined with potentiodynamic polarization curves and electrochemical impedance spectroscopy methods, combined with scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction.

Findings

Corrosion behavior of Zn-Ni composites coating is similar to Zn-Ni alloy coating. In the early stages of immersion, the anodic dissolution of zinc happens, which results in the formation of a zinc hydroxide layer. With the continuous infiltration of chloride ion, zinc hydroxide will get converted to zinc oxide, basic zinc chloride and basic zinc carbonate. The presence of nickel in coatings can prevent zinc hydroxide from converting into zinc oxide.

Research limitations/implications

Further research should be done on improving the deposition efficiency, as the deposition efficiency of low-pressure cold spray is lower than 30 per cent.

Practical implications

Low-pressure cold spray coating can be used in cyclic dry/wet conditions to prolong the life of a steel structure.

Social implications

Low-pressure cold spray Zn-Ni coating is an environmentally friendly anticorrosion method which can be used as an alternative of hexavalent chromium passivation coating.

Originality/value

Zn-Ni composite coating can be deposited on steel directly by low-pressure cold spray by mechanically mixing the powders together. The composite coating also has the same long-term anticorrosion performance as Zn-Ni alloy coating.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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