Paint systems formulated with ion-exchange pigments applied on carbon steel: Effect of surface preparation

Abstract

Ion exchange pigments are a scientifically very interesting alternative to chromates thathave not yet been fully explored. This study considers the following candidate anticorrosive pigments: calcium-exchanged silica (Si/Ca), hydrotalcite/vanadate (HT/V) and calcium bentonite (Bentonite/Ca).Paint systems manufactured with these ion exchange pigments have been subjected to accelerated corrosion laboratory tests: humidity condensation (HC) and salt fog (SF), simulating environments of low and high corrosivity, in order to assess their anticorrosive behavior in comparison with a zinc chromate reference system. For this purpose the degree of coating degradation has been monitored: blistering, underfilm corrosion and delamination from scribe.Electrochemical impedance spectroscopy (EIS) has allowed us to evaluate and quantify the anticorrosive capacity of these ion exchange pigments when incorporated in the paint coating. This paper focuses on the effect of several parameters of interest when designing a paint system: a) sanding treatment of the base steel prior to application of the primer paint; b) pigment concentration in the primer paint coating; and c) application of a topcoat layer over the primer coating.

Cut-edge corrosion behavior assessment of newly developed environmental-friendly coating systems using the Scanning Vibrating Electrode Technique (SVET)

“…This inhibitor is typically prepared by treatment of SiO2 powder with calcium hydroxide (Ca(OH)2) [19]. Several studies showed that the corrosion protection of steel with Ca +2 -SiO pigments could be as good as using conventional chromate species in certain conditions [20,21]. It is known that silicates form complex colloidal structures in an aqueous environment [22].…”

Synthesis of Lithium-exchange Silica Particles for Corrosion Protection of Aluminum Alloys

“…Because of their porous structure and a high specific surface area with OH groups on the surface, silica particles can be modified with inhibitive species, metallic ions, and others by ion-exchange reactions [7, 12−14]. Granizo et al used 10−15% of calcium-exchange silica (Si/Ca) as an inorganic pigment loaded in alkyd coatings to improve adhesion performance and anticorrosion properties for carbon steel substrates [15,16]. Due to cationic-exchange reactions, calcium ions can be released from the corrosive environment and, then, form complex silicate products, such as CaSiO3•FeSiO3, which suppress the corrosion process.…”

Employment of new modified ferrite pigments in anticorrosive alkyd-based paints

“…This has become a major challenge since the last decade for all sectors involving metallic protection (Granizo, 2011). Among various alternatives, ferrite pigments have been introduced as possible replacement of chromate coatings (Jaskova, 2012).…”

“…In the field of anticorrosive primer paints, there is growing interest to find environmentally friendly anticorrosive pigments to replace Cr (VI) pigments which have hazard effect on both the environment and human health. This has become a major challenge since the last decade for all sectors involving metallic protection (Granizo, 2011). Among various alternatives, ferrite pigments have been introduced as possible replacement of chromate coatings (Jaskova, 2012).…”