Search results

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.

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.

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.

This paper aims to formulate and prepare a series of alkyd paints with new anticorrosive pigments, eco-friendly to the environment, based on a natural zeolitic rock modified by ion exchange to incorporate passivating cations.

The electrochemical characterization of the painted steel was carried out by conductivity measurements, linear polarization tests, measurements of the corrosion potential and electrochemical noise measurements. Besides, accelerated tests in standard environmental chambers were also carried out.

The results show that clinoptilolite–mordenite-based pigments incorporated in the paint provide acceptable anticorrosive properties, taking into account their low environmental impact and the use of a natural resource of low cost. The inhibitory efficiency of ZLa is higher than 80% and of ZPr is close to 70%. The electrochemical assays of the coated panels with the alkyd paints ZLa and ZPr shows similar behavior.

In this work, good results were obtained with an alkyd resin, but other resins could be tested. Paints could also be formulated with modified zeolites as a complement to others traditional anticorrosive pigments.

These paints could be used for the protection of metal structures in low corrosive environments.

There are not many published works using zeolites as anticorrosive pigments.

This work aims to study the corrosion protection of laboratory‐prepared micaceous zinc ferrite (MZF) pigment in anticorrosive paints for steel.

Acrylic‐modified alkyd coatings, based on MZF pigment, micaceous iron oxide (MIO) and zinc ferrite (ZF) pigments, were prepared at different pigment volume concentrations “PVCs” to the critical pigment volume concentrations “CPVCs” ratio, which denoted hereafter by A. Scanning electron microscope, weight loss measurements, water vapour transmission (WVT) and immersion in 3.5 per cent salt solution as well as physico‐mechanical properties were performed to evaluate the paints anticorrosive performance.

WVT and corrosion protection can be affected by the PVC/CPVC ratio for all systems. At any particular PVC, the barrier property of the pigment was the main factor affecting the WVT and corrosion protection. MZF pigment protected the carbon steel physically through barrier action and chemically by the reaction with the acidic acrylic‐modified alkyd resin to produce soaps which passivate the substrate.

Novel MZF paint could be used with optimum percentage in anticorrosive paints for steel protection especially in humid and coastal regions.

The paper aims to evaluate the anti‐corrosion performance of inorganic pigments included in paint systems based on plasticized‐chlorinated rubber for carbon steel in different environmental conditions.

Paint systems based on chlorinated rubber and inorganic pigments such as zinc chromate, zinc phosphate, red iron oxide and treated iron industry waste powder were prepared. Immersion in 3.5 percent salt solution, as well as outdoor exposure tests, were performed and the paint physico‐mechanical properties were tested to evaluate the paints' anti corrosive performance.

The concentration and the type of pigments included in the prepared paint systems control their anticorrosive performance.

The paper demonstrates how pigment consisting of treated iron industry waste powder could be used in anticorrosion paints for carbon steel.

Four paint compositions were prepared, two of them based on vinyl copolymer as a binder and the other contain boiled oil in presence or absence of soluble resin material. Boiled oil based paints meet the most anticorrosion action and film property. Also, the anticorrosion potential of the paints depend on the type of ingredients and their ratio in the dry paint films.

Painting of buildings predates civilization. The primary purpose was to add beauty or aesthetics to the built environment. It was also to showcase the level of civilization, taste and fashion drive of the people. However, modern findings have proved that paint (when applied as a finishing coat on buildings) can elongate the service life of such buildings due to some characteristic properties it contains and modern additives that are included at production stage. This paper aims to examine some of the properties inherent in paint through which resistance to failure and better performance is enhanced, aesthetics is maintained and maintenance is reduced. It also examines whether these qualities subsist in all environments. Particular attention is given to its resistance to the impact of saline air when used around the Atlantic Ocean.

The research adopted a qualitative and quantitative approach with empirical analysis in examining the performance of paint used in salt laden environment.

It shows that paint used in an environment where saline air and salt is prevalent begins to deteriorate after two years and requires repainting as against the established norm of five to seven years (5‐7) in areas that are not exposed to saline air. The impact of saline air is significant at p<0.01.

Maximum life span of current paint products in the area is determined to provide adequate information for the preparation of maintenance schedule for painted exterior. Paint with higher resistance to salt attack is required to enhance the longevity of painted exterior in areas at close proximity to sources of salt. Specifying current available paint for exterior finish will be uneconomical and non‐compatible with the principle of sustainability.

The authors made a fresh attempt at investigating the life's span of paint used as exterior finish in salt laden area around the Atlantic Ocean due to the peculiarity of the stresses of the tropical region on external finishes. It also compared the result with existing researches. Differences in paint performance are established.

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.

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.

The prepared complexes exhibit good physical, mechanical and corrosion properties as pigments in paint formulations.

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.

The evaluation of the prepared complex pigments as corrosion resistants was also studied.

It is a simple technique, green synthesis (no solvent used) is involved and high yield is obtained.