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PurposeTo develop a method for the preparation of micaceous zinc ferrite (MZF), anticorrosive pigment having desirable chemical and physical properties.Design/methodology/approachMZF pigment was prepared after firing the oxidised solid molten salts without washing. The MZF pigment obtained was characterised using X‐ray diffraction analysis, crystal size analysis, scanning electron microscope and energy dispersive X‐ray analysis. The pigment obtained was also evaluated chemically with respect to moisture content, content of water‐soluble salts, hydrogen ion concentration (pH) and weight loss; and physically with respect to particle shape, colour, specific gravity and oil absorption. Commercially available micaceous iron oxide and zinc ferrite pigments were also characterised in comparison.FindingsA spinel, MZF pigment was prepared using relevant oxidised solid molten salts. The preparation produced a lamellar structure with a basic nature giving not only barrier protection but also chemical passivation of the substrate.Research limitations/implicationsThe anticorrosive properties of the pigments obtained could be evaluated using more conventional methods such as salt‐spray test.Practical implicationsThe pigment prepared could be used as a highly efficient pigment for anticorrosion coating for steel.Originality/valueThe method for the preparation of MZF pigment was novel. The pigment obtained could be used in various resin systems to produce anticorrosive paints for steel protection.

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PurposeOrganic coatings remain the most widely used way of protecting steel structures from corrosion. Traditional anticorrosive paints contain lead or hexavalent chromium compounds as active pigments. The use of these classical chromates is nowadays restricted by increasing environmental awareness and stringent national and international regulations. An alternative is the use of ion‐exchangeable pigments. The purpose of this paper is to show that cation‐exchanged zeolites can be considered as a safe and efficient alternative to traditional hazardous pigments in protecting steel surfaces.Design/methodology/approachThe new pigments were characterised using different analytical and spectro‐photometric techniques. Characterisation of these pigments using X‐ray diffraction and scanning electron microscopy were done. X‐ray fluorescence was employed to elucidate the concentration of different elements in the prepared pigments. Evaluation of the ion‐exchanged and initial zeolite pigments using international standard testing methods (ASTM) was estimated. Testing the anticorrosive protection of cation‐exchanged zeolites in alkyd paints formulated based on their pigment volume concentration/critical pigment volume concentration was studied, and then these new pigments were applied on cold‐rolled steel panels. The physico‐mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent NaCl for 28 days were tested.FindingsThe results of this work revealed that paint films containing initial Na‐zeolite performed the least protection behaviour, while films including Zn, Ca and Mg‐zeolites were better in their corrosion protection performance, and they can be arranged as Zn‐zeolite>Ca‐zeolite>Mg‐zeolite.Practical implicationsThese pigments can be applied in other polymer composites, e.g. rubber and plastics as reinforcing agent and fillers.Originality/valueThe paper shows that these prepared pigments are environmentally friendly pigments which impart high anticorrosive behaviour to paint films with great economic savings.

Magnesium ferrite pigments were evaluated as active pigments in anticorrosive water‐borne paints. The study includes the use of two different anticorrosive pigment volume concentration (APVC), 15 and 25 per cent and fixed the Q value (the pigment volume concentration/critical pigment volume concentration ratio) in both paint formulations. Epoxy and acrylated alkyd resins were used as binders. The paints were evaluated by accelerated salt spray tests, corrosion tests in condensed water and sulphur dioxide chambers and electrochemical evaluations. The results obtained were compared with reference paints containing zinc ferrite and zinc phosphate pigments. Ferrite pigments passivate the carbon steel directly in the case of neutral epoxy resin binder or indirectly due to the soaps produced as a result of reaction with the acidic acrylated alkyd resin binder. A lower per cent, i.e. 15 per cent of APVC was found to be sufficient to provide satisfactory anticorrosion protection.