Core-shell Pigments Research Articles

Performance of phosphate–alumina pigments in waterborne paints for protection of cold-rolled steel

Core–shell theory presents a new easy method to obtain high performance, economic, and eco-friendly anticorrosive mixed pigments. The core–shell pigments in this work are prepared by depositing a surface layer of an expensive efficient anticorrosive pigment (phosphates) on a bulk of less expensive extender pigment (alumina). The combination of these two compounds led to the production of new pigments with improved properties different from each of its individual components; and consequently these improved properties led to changing the efficiency of protection properties of paint films containing these new pigments. The new pigments were characterized using XRD, SEM, TEM, and EDAX analysis to elucidate their structure and prove the presence of phosphate ions on the surface of alumina. These pigments were also evaluated according to ASTM measurements. Then they were incorporated in three groups of emulsion paint formulations based on styrene acrylic emulsion copolymer, and comprising different concentrations of Zn, Mg, and 1Zn·1Mg phosphates/alumina core–shell pigments; in addition to a control formulation free of these pigments, to evaluate their efficiencies in anticorrosive paints for protection of cold-rolled steel. Chemical, physical, and mechanical measurements were carried out, besides corrosion resistance tests and weight loss of steel panels under paint films which were determined in 5% NaCl solution for 28 days. The results proved that the prepared formulations containing the prepared pigments could protect steel efficiently from corrosion compared to the control specimen. Groups II and III containing higher weight percentages of prepared pigments showed the best performance in corrosion protection, and the best performance among these two groups was paint films containing magnesium phosphate/alumina pigments.

Utilization of new micronized and nano-CoO·MgO/kaolin mixed pigments in improving the properties of styrene–butadiene rubber composites

The present work highlights the role of a new prepared core–shell pigment based on kaolin as the bulk (core) covered with cobalt oxide and magnesium oxide comprising the surface of the pigment (shell). The new pigment was prepared in the micronized and nano-sized particles and its effect on the different properties of styrene–butadiene rubber (SBR) vulcanizates was studied. Incorporation of these two particle sized pigments and their varied content of cobalt oxide to magnesium oxide in the shell of the different pigments in different styrene–butadiene rubber vulcanizates was done, and their effects on the rheological, physical, mechanical and dielectric properties was studied. The study showed that there was a significant effect of these new pigments on SBR properties, and that the optimum micronized pigment loading in SBR was 30 phr, while that of the nano-pigment was 6 phr. The different measured properties were in good agreement with each other.

Study of corrosion inhibition properties of metal oxide based core shell pigments in organic coatings

The objective of this work was to identify the anticorrosive efficiency of synthesised, core pigments. Epoxy ester based coatings containing the synthesised pigments were formulated. To test the anticorrosion properties of the coatings, accelerated corrosion tests were carried out in the environment of condensed water, of NaCl mist, and of condensing water and SO2. The synthesised core shell pigments have good anticorrosion efficiency in an epoxy ester coating. The synthesised pigments do not contain any environmentally harmful substances.

New study of anticorrosive efficiency of core-shell pigments

New study of anticorrosive efficiency of core-shell pigments

Erratum

This article has been withdrawn as it was published elsewhere and accidentally duplicated. The original article can be seen here: 10.1108/00035590810913132. When citing the article, please cite: Nivin M. Ahmed, (2008), “Modified zinc oxide-phosphate core-shell pigments in solvent-based paints”, Anti-Corrosion Methods and Materials, Vol. 55 Iss: 6, pp. 333 - 340.

Study of the anticorrosive efficiency of zincite and periclase-based core–shell pigments in organic coatings

The objective of this work was to identify the anticorrosive efficiency of synthesized, MeO/core pigments and of MeO pigments (MeO = ZnO, MgO) with varied morphology of particles. The synthesized MeO-type pigments displayed varied particle morphologies and the MeO/core core–shell pigments exhibited surface of particles made of zincite and periclase. These core–shell pigments have the properties of both the ZnO layer and of the core (wollastonite or graphite). Epoxy-ester based coatings containing the synthesized pigments were also formulated. To test the anticorrosion properties of the coatings, accelerated corrosion tests were carried out in the environment of condensed water, of NaCl mist, and of condensing water and SO 2. The synthesized core–shell pigments have good anticorrosion efficiency in an epoxy-ester coating.

Core-shell pigments in antifouling paints

Marine fouling is the result of the settling and subsequent growth of organisms on surfaces immersed in seawater. Fouling of ships’ hulls has been traditionally controlled through the use of toxic antifouling paints, but increased ecological awareness and the strict regulations of biocides used in such paints have led to the development of low toxic content or non-toxic coatings to control fouling.