The electric properties of an iron-kaolin functionally gradient material

An idea of gradient functions has recently developed in Japan, giving birth to an entirely new concept in materials. The formal name for the new materials is “functionally graded materials”, or FGMs for short. Methods of manufacture of FGMs vary, but include the chemical and physical vapour deposition methods, the electrolytic deposition method, the atomised metal spray method, and a method in which powdered material is first melted in a plasma jet and then deposited. But none of these methods or other previously existing ones, has allowed the manufacture of a comprehensive range of FGM thicknesses extending from less than 1 millimetre to several centimetres. The authors have developed a new method of FGM manufacture, for which a US patent has been granted. Using this method, it has became possible to produce FGMs across the whole range of thickness from a few millimetres up to several tens of centimetres. We call this new method “successive layer accretion”. The present paper is a report on measured electric properties of an iron-kaolin FGM, namely magnetic permeability, resistance, relative permittivity and transmission loss