Production and characterization of FE2o3/α-al2o3 pigments by the homogeneous precipitation method

Pigment, composed of molecules that make the colors of all objects. Pigments that offer a wide color scale are grouped under two main topics as organic and inorganic pigments. The "luster pigment", an inorganic pigment type, allows the color series of inorganic pigments to be expanded in terms of colourist. Luster pigments have become a focus of attention in pigment studies due to its superior coating properties in addition to its color diversity. Unlike conventional pigments, luster pigments, is composed of at least two different components. These pigments have a different apperance because they are formed from at least three-tier layers. Luster pigments in a group of special effect pigments, a micro-sized plate-shaped base having an aspect ratio of minimum 20, are obtained by coating with a metal oxide having a high refractive index. As a result of the literatüre reviewes, lack of scientific studies on luster pigments have been observed. It has been determined that the initial system and raw material costs are high when the existing literatüre studies are taken into consideration. In this thesis, it is aimed to produce the theoretical and practical knowledge and to eliminate the literatüre deficiency in many production fields which can contribute to the economy of the country when considering the wide range of applications of luster pigments (medicine, cosmetics, food, automotive, construction, ceramics, paper, polymer technology, packaging, etc.). In addition to this purpose, it is aimed to produce and characterize Fe2O3/α-Al2O3 pigments by using homogeneous precipitation method which is cheaper and more practical method of luster pigments. In this thesis, it is aimed to produce the theoretical and practical knowledge and to eliminate the literatüre deficiency in many production fields which can contribute to the economy of the country when considering the wide range of applications of luster pigments (medicine, cosmetics, food, automotive, construction, ceramics, paper, polymer technology, packaging, etc.). In addition to this purpose, it is aimed to produce and characterize Fe2O3/α-Al2O3 pigments by using homogeneous precipitation method which is cheaper and more practical method of luster pigments. In this thesis study, pH value of the system was fixed with aqueous NaOH solution. Then, the optimum points of these parameters were determined by examining the effects of the mixing speed of the production stage and the flow rate, the number of washes and the calcination temperature of the titration stage on the product. In additıon, detailed crystallographic analysis of the produced pigments were determined by X-ray diffraction (XRD) technique analysis. The properties of the microstructures are characterized using scanning electron microscopy (SEM) based analytical (energy-dispersive X-ray (EDX)) techniques. The color properties of the produced powders were determined with the help of a spectrophotometer (L * a * b *). When the results of the characterization techniques are examined, the plate-shaped α-alumina (α-Al2O3) powders coated with a hematite (Fe2O3) layer with a high refractive index were successfully synthesized/production by homogeneous precipitation.