Method and device for measuring the resistance of materials in the layers by photothermal radiometry

摘要

The invention relates to a method and a device for measurement by photothermic radiometry of the contact thermal resistance of metallic materials in layers. A modulated beam of electromagnetic radiation is focused on the free surface S of the material so as to excite (stimulate) this free surface over an excitation region of determined radius rg. The d.c. (continuous) component (T1(r,o)) and a.c. (alternating) (@(r,o)) components of the temperature distribution of the free surface S of the material are determined from the heat equation. The a.c. component of the infrared IR radiation is detected at the free surface S of the material. The a.c. component of the photothermic signal @ emitted by the free surface S of the material is determined from the a.c. component of the infrared IR radiation and from the a.c. and d.c. components of the temperature distribution of the free surface S. The a.c. component of the photothermic signal @ is compared with a plurality of calibration values characteristic of the contact resistance R of known samples of the material in order to determine the value of the contact resistance for the material in question. IMAGE