Method of determining thermal coefficient of materials

Claim 1

A method for determining thermal conduction coefficient of a material sample having two opposite surfaces, compriisng the steps of: placing said material sample in a system composed of a heater, a first and second heat sinks, a first and a second identical reference samples having known thermal conduction coefficients, said first reference sample being in thermal contact with the first heat sink, said second reference sample being in thermal contact with the second heat sink, said material sample and said heater being positioned between the first and the second reference samples and maintaining thermal contacts therewith; supplying an amount of heat in a time unit by the heater so as to give rise to a heat flux across the samples; measuring sasid amount of supplied heat during a preferably continuously linear change of the temperature of said heat sinks; measuring a momentary temperature difference between the two opposite surfaces of the material sample; and determing the thermal conduction coefficient of the material sample for the momentary temperature of the system on the basis of the following equation: ##EQU25## wherein: λ is the thermal conduction coefficient of the material sample; P is the amount of heat supplied by the heater in a time unit; 1is the thickness of the material sample; s is the surface of the heater; Δt is the momentary temperature difference between surfaces of the material sample; λ 1 is the thermal conduction coefficient of the reference samples; and 1 1 is the thickness of the reference samples.

Claim 2

A method for determining thermal conduction coefficient of a material sample having two opposite surfaces, compriisng the steps of: placing said material sample in a system composed of a heater, a first and second heat sinks, a first and a second identical reference samples having known thermal conduction coefficients, said first reference sample being in thermal contact with the first heat sink, said second reference sample being in thermal contact with the second heat sink, said material sample and said heater being positioned between the first and the second reference samples and maintaining thermal contacts therewith; supplying an amount of heat in a time unit by the heater so as to give rise to a heat flux across the samples; measuring sasid amount of supplied heat during a preferably continuously linear change of the temperature of said heat sinks; measuring a momentary temperature difference between the two opposite surfaces of the material sample; and determing the thermal conduction coefficient of the material sample for the momentary temperature of the system on the basis of the following equation: ##EQU25## wherein: λ is the thermal conduction coefficient of the material sample; P is the amount of heat supplied by the heater in a time unit; 1is the thickness of the material sample; s is the surface of the heater; Δt is the momentary temperature difference between surfaces of the material sample; λ 1 is the thermal conduction coefficient of the reference samples; and 1 1 is the thickness of the reference samples.