When cadmium is added to copper, the material becomes more resistant to softening at elevated temperatures. The more cadmium that is added, the more heat resistant the material becomes. Cadmium copper is used in applications such as trolley wire, heating pads, electric blanket elements, spring contacts, connectors, and high strength transmission lines. It is also used for soldering applications, particularly to join components in automobile and truck radiators and semi-conductor packaging operations.