A METHOD OF THERMAL CONDUCTIVITY MEASURING

A subject matter of the invention is to provide a method of measuring high values of thermal conductivity (higher than 10 W/mK) of solid bodies - metals, ceramics, glass, plastic. The measurements by this method are carried out under steady-state conditions when the thermal conductivity can be calculated from the temperature gradient and the rate of heat flow through the sample. An object of present invention is to simplify the measurements procedure by providing a constant heat flow through the different samples independently of their thermal conductivity, dimensions and geometrical form. The point of invention is that the heat flow is supplied and/or left on sample through a thin layer having low heat conduction. A thickness of this layer is chosen that its heat transfer resistance (the relation of layer thickness to thermal conductivity of this layer) is at least ten times higher than that of examined sample. This invention can be applied mainly in the measurement and control over thermal conductivity of solid bodies (such as metals, ceramics, glass, plastic) possessing a good thermal conductivity (higher than 10 W/mK). It is based on the rule of thermal physics determining the relation between the thermal conductivity of a material and the temperature gradient in the sample, which emerges, if a certain and constant heat flow is carried through it.The goal of the invention is to simplify the measuring procedure, ensuring equivalent heat flow for different samples, regardless of their thermal conductivity, dimensions, and geometrical form, while under the same measuring conditions.The principle of the invention: the heat flow is provided or drained through a thin layer, possessing low thermal conductivity. The thickness of the layer is chosen in such a way that its resistance to the heat transfer (the relation between the thickness and the thermal conductivity) is at least ten times larger than for the tested sample.