A theoretical and experimental relationship between the leakage of gases through the interface of two metals in contact and their superficial micro-geometry

Abstract The flowing rate of a gas through the interface to two metallic surfaces in contact is in close connexion with their micro-geometries. The calculation shows that the interfacial conductance is proportional to the square of the mean roughness of the surfaces. We measured experimentally (1) the interfacial conductance of the pieces in contact; and (2) the mean roughness of the surfaces. Experimental and theoretical results are in a good agreement. This allows a comprehensive description of the phenomena which occur at a metal-to-metal contact especially from the leak rate viewpoint and permits a measurement of the mean roughness of the surfaces in contact under loading.