Characterization of composite mixture of scale and pigment to synthesize anti-corrosive coating

The objective of this work is to characterize two materials in order to synthesize anticorrosive coating. These materials are an oolitic iron oxide pigment containing phosphorus and a by-product of steel making that should be recycled. The characterization of these two components took place in the URASM / CRTIAnnaba laboratories. Chemical analysis showed that the pigment contains 53.18% iron and a siliceous gangue. The scale contains 73.83% iron as iron oxides (FeO, Fe3O4 and Fe2O3). Grinding tests have shown that the scale is much more suitable for grinding than pigment. A volume distribution of particles ranging in size from 0.7 to 32 microns for the scale and from 0.6 to 40 microns for the pigment; their specific areas are between 1.6 and 1.5 m2/g. TGA and DSC analyzes have shown that the pigment loses weight with phase dissolution by consuming energy as the temperature increases. The scale is gaining weight by forming a new phase with heat. At SEM, the iron pigment is in the form of an aggregate of grains surrounded by gangue. Scale showed a homogeneous structure composed of iron oxide grains of sizes and shapes ranging from 1 μm to 10 μm. X-ray diffraction analysis showed that the iron in the pigment was in the form of hematite and goethite. A tiny portion is combined with silica as Fe2SiO4. Iron in Scale is in the form of three oxides (FeO, Fe2O3 and Fe3O4). The different coating formulations used have shown that a mixture of 71.43% pigments and 28.57% scale has the best corrosion resistance, resulting in low current and low corrosion rate.