Microscopic analysis of interfacial electrothermal phenomena––definition of a heat generation factor

The thermal state at a solid–solid contact with interfacial heat generation requires the knowledge of two macroscopic contact parameters: the thermal contact resistance (RTC) and the heat generation factor (α). RTC is already well defined by many theoretical models, on the other hand, α remains poorly known and was never studied in the case of electro-thermal contact. On the basis of a microscopic analysis of the coupled electrical and thermal phenomena in a current tube crossing two asperities in contact, we propose a model of the heat generation factor. This one is a combination of electrical resistivities and thermal conductivities of both materials in contact. Comparison of model to experimental data are presented and discussed.