Fernico is an alloy of Iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 (Fe), Nickel

Nickel

Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

 (Ni) and Cobalt

Cobalt

Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

 (Co). The abbreviation forms the name which is (or was) a trademark

Trademark

A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

. The alloy has the same linear coefficient of expansion as certain types of glass, and thus makes an ideal material for the lead out wires in light bulbs and thermionic valves.

Cunife

Cunife

Cunife is an alloy of copper , nickel , iron , and in some cases cobalt . The alloy has the same linear coefficient of expansion as certain types of glass, and thus makes an ideal material for the lead out wires in light bulbs and thermionic valves...

exhibits a similar property.