Characterization of thermal transport across single-point contact between micro-wires

A contact transient electrothermal technique (CTET) is developed to characterize the thermal transport between one-dimensional conductive and nonconductive microscale wires that are in point contact. This technique is a significant advance from the transient electrothermal method that is used to characterize the thermophysical properties of individual one-dimensional micro-wires. A steady-state analytical solution and a transient numerical solution are used to independently determine the value for the thermal contact resistance between the wires at the contact point. The CTET technique is applied to measurement of the thermal contact resistance between crossed Pt wires (25.4 μm diameter) and the thermal contact resistance between a glass fiber (8.9 μm diameter) in contact with a Pt wire (25.4 μm diameter). For Pt wire contact, the thermal contact resistance increases from 8.94×10⁴ to 7.05×10⁵ K/W when the heating current changes from 20 to 50 mA. For the Pt/glass fiber contact, the thermal contact resistance is much larger (2.83×10⁶ K/W), mainly due to the smaller area at the contact point.