Experimental thermal study of contact with third body

The thermal study of sliding contact is complex due to numerous physical aspects highly coupled. Heat generation mechanisms are still badly known due to the complex interactions between mechanical, thermal and physico-chemical behaviors and surface degradations. In the thermal field, the literature generally classify the sliding contact as perfect or imperfect contact, depending if the asperities are taken into account. In the both cases thermal continuity at the interface of the two sliding bodies is assumed. Few studies consider a contact with third body. It is usually neglected because of its weak thermal conductivity.In the goal to better appreciate the third body role on the thermal aspect, an experimental set-up has been realized. It consists in two rings sliding to each other, the first one is made of sapphire (rotating ring) and the second one is made of steel (fixed ring). The temperatures are obtained by an infrared camera scanning through the sapphire and by thermocouples on the contact surface specially realized for this experimental set-up. The contact surfaces of the two rings have been observed with a scanning electronic microscope. Comparison between the thermal scene and the surface observations has allowed to connect the third body accumulation with local surface heating.