Electrical conductivity of potassium polyferrite doped with doubly charged cations

Abstract

To clarify the charge compensation mechanism and the way of alloying additives placement, the authors synthesised samples of potassium βʺ-polyferrites with a wide range of mole fraction of introduced doubly charged cations. For these samples, the authors measured the electronic conductivity, cationic conductivity, and performed X-ray diffraction (XRD) analysis. The authors identified the charge compensation mechanism in potassium β″-polyferrite when doped with divalent ions of calcium, strontium, magnesium, and zinc. The charge compensation mechanisms differ depending on the radius of the introduced doubly charged ion. The results of cationic conductivity measurements of potassium β″-polyferrites show the mobility reduction of large calcium and strontium cations of potassium ions. Such additives are quite promising for improving the mechanical strength and thermal stability of the catalyst granules. They also increase the chemical stability of the contact granules. Corrosion resistance of pellets is a critical parameter. It determines the period of effective functioning of the catalyst. The data on electronic conductivity allow one to conclude that the introduction of Mg2+, Zn2+ cations sharply reduces the electron exchange in the structure of potassium β″-polyferrite. This should inevitably cause deactivation of the catalyst, while Ca2+ and Sr2+ ions do not reduce the electron transfer rate. Moreover, using the proposed approach will intensify the research process.