سال انتشار: ۱۳۸۷

محل انتشار: دومین کنگره بین المللی علوم و فناوری نانو

تعداد صفحات: ۲

نویسنده(ها):

M. Gharagozlou – Department of Nanotechnology and Nanomaterials, Institute for Colorants, Paint and Coatings

چکیده:

Nano-sized pigments of the spinel type, which are characterized by the stability of their properties under the effect of various factors, gain a considerable interest in a view to their application in various industrial processes and also for fundamental understanding of the very different properties of the same material when the particle size approaches the atomic scale level [1]. The particular surface effect, volume effect and quantum size effect [2] become apparent because the ratio of the surface atomicity to the bulk atomicity of nanometer particles increase sharply when the diameter of nanometer particles decrease. Therefore, nanometer particles have a series of new physical chemical characteristics, which makes them have considerable application prospects in adsorption, optics, pigments, catalysis, electricity and magnetism, etc. In order to obtain pigments with high quality, there are important factors; synthesis method determines not only stoichiometric and morphologic control but also physical and chemical properties. Many works present the synthesis of spinel using the conventional ceramic powder preparation process, which involves a solid state reaction. This method has some disadvantages for advanced applications, such as formation of strongly bonded agglomerates, poor sintering behavior, non-homogeneities, such as undesirable phases, abnormal grain growth, poor reproducibility, high calcinatory temperature up to 1300οC and imprecise control of cation stoichiometry and ratios [3]. In order to improve the properties of pigments, chemical methods have been investigated in the last years [4]. These methods lead to a more precise stoichiometry and good sinterability, besides particle size and morphology control [5]. Therefore, in this work we report chemical synthesis and characterization of black spinel pigment nanoparticles which calcined at different temperatures. Proper preparation conditions were investigated via a series of experiments. The black spinel pigment nanoparticles obtained were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), colorimetric analysis (L*a*b* color parameters) and diffuse reflectance. Our results show this chemical method does not require high temperature calcinations and also permits good stoichiometric control as well as reproducibility and purity.