Investigation of thermal resistance at the interface of dissimilar and similar metals

Experiments have been conducted to investigate the resistance and the effect of the directional heat flow at the interface of metals in contact. The test specimens were cylinders, axially aligned and dead weight loaded. Specimen materials were aluminum, bronze, and steel. The tests were conducted at environment pressures of 5x10⁻⁵ Torr. or less. The dead weight load was kept at 10 lbs. for all tests and the surface roughness for all specimens was from 6 to 8x10⁻⁶ inch. The results of the investigation reveal that the resistance to heat flow at the interface of metals decreases as the interface temperature increases. Appreciable directional heat flow effects were found for dissimilar metals. The larger the difference of conductivities of matching materials, the more serious the directional heat flow phenomenon. This paper further confirms that there may be an existing potential barrier created by the temperature difference and the properties between dissimilar metals --Abstract, page ii