Search results

1 – 10 of 186
To view the access options for this content please click here
Article
Publication date: 1 June 1999

L.S. Hernández, B. del Amo and R. Romagnoli

Substitution of zinc chromate or zinc yellow, traditionally used as anticorrosive pigment, for other phosphate‐based pigments that are not hazardous to health and have the…

Abstract

Substitution of zinc chromate or zinc yellow, traditionally used as anticorrosive pigment, for other phosphate‐based pigments that are not hazardous to health and have the same anticorrosive behaviour or even better, is studied in this paper. Four alkyd paints were specially prepared; two of them contained calcium acid phosphate or micronised zinc phosphate as anticorrosive pigments respectively. A paint containing zinc chromate was used as reference and a paint without anticorrosive pigments was used as a blank, in which the other ingredients were increased proportionally to attain the desired PVC relationship. The corrosion behaviour of low carbon steel panels coated with these paints in a 3 per cent NaCl solution was assessed by electrochemical impedance spectroscopy (EIS). In addition, other painted panels were evaluated by salt spray and humidity chamber tests. Results of all tests showed that the paint with calcium acid phosphate and especially that with micronised zinc phosphate exhibited better behaviour than paint with zinc chromate. Analysis of impedance parameters (ionic resistance and capacitance of the paint film) against immersion time allowed the paints to be ranked in the same order as that obtained with salt spray and humidity chamber tests.

Details

Anti-Corrosion Methods and Materials, vol. 46 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

To view the access options for this content please click here
Article
Publication date: 1 February 2001

M. Deyá, V.F. Vetere, R. Romagnoli and B. del Amo

The efficiency of two anticorrosive pigments containing aluminium polyphosphate was studied. Pigments were analysed by current analytical techniques and characterised by…

Abstract

The efficiency of two anticorrosive pigments containing aluminium polyphosphate was studied. Pigments were analysed by current analytical techniques and characterised by FT‐IR spectrometry. The anticorrosive properties of the selected pigments were evaluated following the electrochemical behaviour of a steel electrode in pigments suspensions. In a second stage, solvent‐borne paints with 30 and 10% v/v of the pigment and PVC/CPVC (pigment volume concentration/critical pigment volume concentration) ratio 0.8 were formulated. Three resins were chosen as film forming materials: an alkyd, an epoxy and a vinyl. The performance of the resulting anticorrosive paints was assessed by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential, ionic resistance and polarisation resistance). The anticorrosive performance of the tested paints was closely related with pigment composition. The nature of the resin was also of importance; in this sense, epoxy paints showed the best anticorrosive performance. Good correlation has been obtained between accelerated and electrochemical tests.

Details

Pigment & Resin Technology, vol. 30 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 1 April 2000

G. Blustein, B. del Amo and R. Romagnoli

The objective of this work was to study the anticorrosive behaviour of three commercial pigments containing micronized zinc phosphate. The chemical analyses of the…

Abstract

The objective of this work was to study the anticorrosive behaviour of three commercial pigments containing micronized zinc phosphate. The chemical analyses of the pigments were carried out in the laboratory to characterise them with respect to their composition and soluble matter. It was proposed to check pigments’ efficiency in solvent‐borne paints with 30 per cent v/v of the pigment by volume and a pigment volume concentration/critical pigment volume concentration ratio (PVC/CPVC) equal to 0.8. The behaviour of paints formulated with two binders (alkyd and epoxy) was assessed by accelerated (salt spray cabinet, humidity chamber and accelerated weathering) and electrochemical (corrosion potential, ionic resistance and polarisation resistance) tests. It was demonstrated that pigment performance is highly influenced by their solubility which, in turn, could influence the formation of the protective layer on the metal substrate. Good correlation was obtained between salt spray and electrochemical tests.

Details

Pigment & Resin Technology, vol. 29 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 1 February 2001

M. Pérez, M. García, V. Vetere, M. Deyá, B. del Amo and M. Stupak

Owing to present and expected future regulations on the use of polluting antifouling compounds, there is a growing need for alternative methods for the prevention of…

Abstract

Owing to present and expected future regulations on the use of polluting antifouling compounds, there is a growing need for alternative methods for the prevention of biofouling. Some experiments on the effect of iron benzoate, as a possible biocide agent, on nauplii of Balanus amphitrite were carried out. This pigment was used because it is rapidly hydrolysed and consequently it produces a pH decrease. Although anion benzoate has an intense narcotic effect on nauplii, the results clearly demonstrated that the combined action of this compound and a pH decrease (generated by iron benzoate hydrolysis) produce a pronounced antifouling activity, i.e. the synergic effect is greater than separate effects.

Details

Pigment & Resin Technology, vol. 30 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 1 February 2000

J.J. Caprari, A.R. Di Sarli and B. del Amo

Health and safety legislation has forced changes in the type of anticorrosive pigments used in paint formulations, mainly focused on their substitution with different…

Abstract

Health and safety legislation has forced changes in the type of anticorrosive pigments used in paint formulations, mainly focused on their substitution with different phosphates. The zinc phosphate pigment used with different types of binders has provided contradictory experimental results. In this paper, waterborne anticorrosive paints pigmented with zinc phosphates were studied. The main variables considered were PVC and the anticorrosive pigment content. Accelerated tests (salt spray, humidity chamber, and electrochemical tests) were performed to evaluate the paints’ anticorrosive performance. Good correlation was found using salt spray and impedance tests. From analysis of the time dependence of all the experimental results it was concluded that an efficient steel protection could be obtained using a waterborne epoxy primer pigmented with zinc phosphate. Such protection is attained through the barrier effect afforded by the paint film as well as the precipitation of a pretty stable ferric phosphate layer under the intact and damaged coating areas.

Details

Pigment & Resin Technology, vol. 29 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 1 July 2006

P. Kalenda, A. Kalendová and D. Veselý

To identify the dependence of the anticorrosion efficiency of chemically varying pigments on their concentration in steel protecting paints.

Abstract

Purpose

To identify the dependence of the anticorrosion efficiency of chemically varying pigments on their concentration in steel protecting paints.

Design/methodology/approach

Anticorrosion pigments from a group of nontoxic substances were chosen and compared with a chromate pigment. With all pigments, the following parameters were observed namely, oil absorption, critical pigment volume concentration value, density, extract pH, specific surface, particle size, water‐borne substances content, and the specific electrical conductivity of pigment extracts. The aqueous extracts of pigments were used to determine the corrosion loss of steel. The morphology of pigment particles was observed by means of an electron‐scanning microscope. Paints containing these pigments were formulated on the binder basis of an epoxy resin. The paints prepared were subjected to measurement of physical‐mechanical properties such as hardness and resistance in deep drawing. Paints containing anticorrosion pigments were subjected to corrosion tests in a SO2 condenser chamber, salt spray cabinet and to a test according to Machu and Schiffman.

Findings

The experimental investigations revealed the absolute values of the anticorrosion effects of individual pigments as well as dependence of efficiency on the concentration of the pigments in the paints. It was found that environment‐friendly pigments achieved comparable or even better anticorrosion efficiency than toxic strontium chromate.

Research limitations/implications

The anticorrosion properties of the paints concerned can be tested in paints by means of atmospheric exposure such as the Florida test.

Practical implications

The results find their application in the formulation of anticorrosion paints for industrial applications with environment‐friendly effects.

Originality/value

This research paper presents the results of the anticorrosion effects of a great number of industrially used pigments. Based on this paper, the formulation of highly effective steel‐protecting paints can be optimised.

Details

Pigment & Resin Technology, vol. 35 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 6 March 2017

Santiago Flores Merino, Juan José Caprari, Luis Vasquez Torres, Luis Figueroa Ramos and Antonella Hadzich Girola

The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of…

Abstract

Purpose

The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water based rust converter.

Design/methodology/approach

Water-borne acrylic primers were formulated with tara powder and aqueous tara extract and applied on steel rusted by three different methods. The conversion of rusted steel by tara tannins was studied by X-ray diffraction spectroscopy, infrared spectroscopy and scanning electron microscopy. The acrylic primers, containing hydrolysable tannins, were coated with alkyd finish and were evaluated in comparison to commercial systems in accelerated corrosion tests. The corrosion inhibition effects of tara powder on mild steel in 0.1M NaCl were studied by DC electrochemical techniques.

Findings

Tara tannin converts rust to ferric tannate and increases the magnetite content of rusted steel. The water-based acrylic primer formulated with aqueous extract of tara, alkyd-coated finish, showed performance equivalent to pure alkyd system.

Research limitations/implications

The chlorides content in the commercial tara powder can be screened the beneficial effect of hydrolysable tannins to convert rust. Furthermore, the water-based rust converter formulated with acrylic resin may be sensitive to salt contamination of rust.

Originality/value

Hydrolysable tannins from commercial tara powder have not been studied yet in its application to the development of rust converters. A water-based primer formulated with commercial tara powder developed for the effective treatment of rusted surfaces can be of interest as an environmentally friendly to current commercial approaches.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

To view the access options for this content please click here
Book part
Publication date: 30 November 2020

Christian Stache

It is widely accepted among critical human–animal scholars that an absolute ontological distinction between humans and animals, the human–animal dualism, is an ideological…

Abstract

It is widely accepted among critical human–animal scholars that an absolute ontological distinction between humans and animals, the human–animal dualism, is an ideological construction. However, even some of the most radical animalists make use of a softer version of it when they explain animal exploitation and domination in capitalism. By criticizing the reintroduction of the human–animal dualism through the back door, I reopen the terrain for a historical–materialist explanation of bourgeois animal exploitation and domination that does not conceptualize them as a matter of species in the first place. Rather, with reference and in analogy to ecosocialist arguments on the greenhouse effect, it is demonstrated that a specific faction of capital – animal capital – which uses animals and animal products as means of production, is the root cause, key agent, and main profiteer of animal exploitation and domination in the current mode of production. Thus, the reworked concept of animal capital presented here differs from the original, postoperaist notion introduced by Nicole Shukin since it is based on a classic sociorelational and value theoretical understanding of capitalism. According to this approach, animals are integrated socioeconomically into the capitalist class society via a relation of superexploitation to capital, which can be called the capital–animal relation.

To view the access options for this content please click here
Article
Publication date: 1 June 2003

P. Mošner, A. Kalendova´ and L. Koudelka

Twelve pigment compositions derived from the xCaO·(50−x)ZnO·20B2O3·30P2O5·(x=10, 20, 30) and yMgO·(50−y)ZnO·20B2O3·30P2O5·(y=10, 20, 30) systems were prepared. The…

Abstract

Twelve pigment compositions derived from the xCaO·(50−x)ZnO·20B2O3·30P2O5·(x=10, 20, 30) and yMgO·(50−y)ZnO·20B2O3·30P2O5·(y=10, 20, 30) systems were prepared. The synthesis was carried out either by the medium‐temperature process or by the high‐temperature process followed by cooling in air and an isothermal crystallisation of the glass obtained. The pigments prepared by the medium‐temperature process achieved better corrosion results in styrene‐acrylate coating formulations, whereas those prepared by the high‐temperature process achieved better results in alkyd‐resin coating formulations. The anti‐corrosion results for the Ca‐Zn pigments were better than those for the Mg‐Zn pigments.

Details

Pigment & Resin Technology, vol. 32 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
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

Keywords

1 – 10 of 186