Effect of Structural Anisotropy on Contact Properties in a Silver - Graphite Composite

We have studied the effect of structural anisotropy on the contact properties of silver –5 mass% graphite composite. We have established that the highest erosion resistance is typical of contacts with a structure in which the flake-shaped graphite particles are located perpendicular to the working surface. Welding resistance is higher in contacts with a structure in which the graphite particles are located parallel to the working surface of the contact. We have shown that for any arrangement of the graphite particles in the silver matrix, contacts with an anisotropic structure made from bars obtained by extrusion are distinguished by a higher erosion resistance compared with contacts prepared by single pressing - sintering - final pressing - annealing. The results obtained are of practical importance for designing electrical contacts to be used in low-voltage automatic switches. They make it possible to improve the operating characteristics of silver - graphite composite materials.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 101–105, January–February, 2005.