Copper and Copper Alloys

Copper has made possible the continued, efficient development of the electrical industry because it has the highest conductivity of the commercial metals. In addition, it has favorable mechanical properties at low, ambient and elevated temperatures, is easily fabricated or cast to shape and can be readily machined. Copper also has excellent resistance to oxidation and corrosion. The thin oxide layer that does form is conductive; meaning that properly made connections will have a long service life and will not deteriorate over time. From high voltage transmission cables to microcircuits, and from megawatt generators to computers, in every aspect of electrical generation, transmission and use, copper is the essential, energy-efficient metal.

Modern electronic and computer technology has created requirements to meet extremes of service conditions that demand very special materials. For example, tensile strengths greater than 200 ksi (1400 MPa) can be achieved in heat-treatable alloys such as beryllium coppers; therefore such materials are often selected for heavy-duty industrial and military electrical connectors.

Copper's high electrical conductivity is matched by excellent thermal conductivity, which makes copper the first choice for heat exchanger applications. Good examples are the recently developed brazed copper-brass automobile radiators that are fully competitive with aluminum counterparts in terms of thermal efficiency and light weight, and are significantly more durable.

Copper and its alloys represent 6 - 9% by weight (or approximately 50 - 55 lb, 23-25 kg) of the content of a typical automobile. Copper itself is essential for the full wiring harness, alternator and starter motor windings and other motors and actuators. Copper alloys are used for conductive spring clips, terminals and connectors. Copper alloys are also used for bearings, gears and valve guides, radiators, hydraulic tubing, and fasteners. Small, machined components can be made cheaper in brass than in steel, and, for automotive applications, generally do not need expensive protection against corrosion. Copper is also an essential component of aluminum alloys used for engine blocks, cylinder heads and other automotive castings. And, copper is beginning to play an important role in electric and hybrid vehicles, in starter motor/generators, drive motors, circuitry and as the cathode in recently commercialized nickel-metal hydride batteries. In all, the copper content of future vehicles may be three times that used today.