On the separation of the contributions of powder particle cores and intergranular contacts to the electric resistivity of the compressed powder materials

Since the early measurements of Skaupy and Kantrowitc3¹ it is well-known that the electric conductivity of powder materials exhibits various, very complex problems. However, for a long period of time, the principal interest in the electric conductivity of conducting powders was focused to its application on carbon brushes², sintered electric contacts³ and electrochemical batteries⁴. The most prevailing sintering of metallic or ceramic parts was not affected by the electric conductivity of the raw powder. During the last years, however, electric heating methods, e.g. flash sintering, inductive sintering etc., have been developped and have partly been introduced into the sintering practice. One of the most urgent problems of these new procedures is the powder resistivity. Again, the most important problem of measuring powder resistivities is the separation of the contribution of powder particle cores and surfaces to the entire resistivity of the green powder pressing, before the heating process starts. A few considerations and experimental result will be given here below.