Patent attributes
An electrode is formed of a bismuth brass alloy. The bismuth brass alloy contains about 30 weight percent to about 40 weight percent of zinc, about 1 weight percent to about 10 weight percent of bismuth, and the balance copper. The bismuth brass alloy has a microstructure that includes islands of bismuth dispersed within the base metal formed of copper and zinc and also includes bismuth at the grain boundaries of the base metal. As a large bulky atom with high resistivity against fluorine attack, bismuth segregates at the grain boundaries and blocks the fluorine diffusion into the lattice. In the presence of fluorine, the bismuth brass alloy forms a protective layer on the elongated surface of the body of the electrode. This protective layer inhibits reaction of the base metal formed of copper and zinc with fluorine and thereby preserves the surface of the electrode material.
