Circuit breaker contact containing silver and graphite fibers

A method of producing an electrical contact material of silver and graphite fiber which comprises the steps of

• mixing quantities of silver powder, graphite fiber particles, wetting agent powder, a solution of a lubricant and a solvent to provide a homogeneous mixture of ingredients and including from about 0.5 to about 10 weight percent of graphite fiber particles, from about 0.1 to about 3 weight percent of powdered wetting agent selected from the group consisting of Ni, Fe, Co, Cu, Au, and mixtures thereof, the solution being a slurry of a volatile hydrocarbon solvent and of a lubricant selected from the group consisting of polyethylene glycol, paraffin, and stearic acid, and the residual part consisting of silver powder;
• drying the mixture of ingredients to eliminate the volatile solvent and to produce a dried mixture;
• screening the dried mixture to agglomerate the ingredients into clusters;
• pressing the dried mixture under a pressure of from about 7.5 to about 10 tons per square inch to form a solid briquet;
• heating the solid briquet from about 250.degree. F. to about 450.degree. F. for about one hour at each temperature of 250.degree. F., 350.degree. F., and 450.degree. F., in air to bake out the lubricant;
• sintering the solid briquet at temperature range of from about 1500.degree. F. to 1700.degree. F. in a reducing atmosphere to shrink the briquet to a higher density;
• repressing the solid briquet under a pressure of about 50 tons per square inch to increase the density;
• resintering the solid briquet at a temperature of from about 1500.degree. F. to about 1700.degree. F. in a reducing atmosphere to anneal stress from repressing;
• and
• re-repressing the solid briquet under a pressure of from about 50 to 60 tons per square inch.