Contact Resistance/Thermal Conductivity Test Rig

Two test rigs are available for measuring thermal resistance between contacting surfaces. A measured one-dimensional heat flow is passed through a vertical column consisting of a heat source, two heat flux meters, a cold plate and the test sample. To ensure one-dimensional heat flow, the entire apparatus is contained within a vacuum chamber capable of 10^-6 torr using a combination of a mechanical and a diffusion pump. A contact pressure between 0.4 and 9.0 MPa can be applied to the interface using a linear actuator. A mean interface temperature between 50 ^oC and 250 ^oC is attained through control of the heater block and the constant temperature bath supplying the cold plate. The surrounding environment within the vacuum chamber can be purged with various gases, such as helium or argon. Data acquisition and control over the experiment are performed using Keithely data logger connected to an IBM PC compatible computer.

The test rigs can also be used to measure the thermal conductivity of a material in accordance with ASTM D5470. The thermal resistance vs. sample thickness is used to determine the joint resistance as a function of bulk resistance and contact resistance. The thermal conductivity is then determined based on bulk resistance and sample thickness.