Use of functionally gradient material in a temperature measuring element

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 gradient materials", or FGMs for short. Application fields for FGMs are found throughout the various sectors of engineering. None of the methods of manufacture or other previously existing ones, 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 "progressive lamination". The present paper examines the resistance-temperature properties of material manufactured by this method. It is found that measurements of temperature differences down to as small as 0.1/spl deg/C are practicable. The material is well within the range of suitability for use as a thermistor.