METHOD OF PREPARING AN ELECTRICAL CONTACT MATERIAL

摘要

The instant invention relates to a method of preparing an electrical contact from sub-micron size silver particles and less than two micron size cadmium oxide particles with the contact having finally dispersed particles of cadmium oxide within grains of silver. In the instant invention particles of silver and cadmium oxide are intimately blended together and subjected to a reducing atmosphere at a temperature of from 321.degree.C to 550.degree.C to reduce the cadmium oxide and form an alloy powder of cadmium and silver. The mixture is held at an elevated temperature following reducing and then oxidized at a temperature of from 321.degree.C to 550.degree.C to precipitate a dispersion of cadmium oxide within the grains of silver. Lithium in a suitable form is then added to the resultant silver cadmium allow powder. In an alternative embodiment an alloy powder of cadmium and silver already prepared from sub-micron size particles of silver and less than 2 micron size particles of cadmium oxide is heated to a temperature of from 321.degree.C to 550.degree.C in an inert atmosphere. The inert atmosphere is then changed to an oxidizing atmosphere at that temperature to precipitate the dispersion of cadmium oxide within the grains of silver and then lithium is added in a suitable form. The material as prepared by both embodiments is then formed into an electrical contact. The instant also relates to the electrical contact produced by the methods of the invention.