Specific behavior of electrolytic copper powders of different morphological forms in temperature fields

An important goal of materials science is the development of copper powders, which are used as catalysts in reactors based on fluidization bed technology. These reactors are more economical and efficient than the reactors with fixed catalytic layer. However, such reactors put special requirements to the catalysts. The catalyst should be stable in the temperature fields, have high thermal conductivity and wear resistance, certain shapes and sizes of the active particles. Сopper powders with approximately the same average particle size, but with different internal structures and surface morphologies were obtained by electrolytic method in this work. A comparative analysis of the results of exposure to temperature fields was also performed. The heating of powders was carried out in a differential scanning calorimeter (X-DSC 7000). Investigations of surface morphology and phase composition changes of the copper powders particles were performed using scanning electron microscopy and x-ray diffraction. It has been shown that particles with different initial structures and morphologies have similar morphological and phase transformations in the process of annealing in air (sintering and loss of particles faceting, the growth of whiskers and oxidation, the formation of cavities inside and pores on the surface). Nevertheless, for the icosahedral small particles of copper, there is an increased release of energy during the heating in DSC, and this energy activates and accelerates structural-phase transformations in the particles. By authors’ opinion, this can be related to particular features of the internal structure and morphology of their surface.