Copper and copper-based alloys are established materials in electrical, electronic and also in more general engineering applications (e.g. bearing
assemblies). Not all are acceptable for space, so discussion is limited to those alloys which were evaluated and to specific comments relating to their use in space.
The main applications for copper are in electrical and electronic subsystems (wiring, terminals in soldered assemblies) and plating (e.g. electronics, thermal control and corrosion protection). Copper is also used as a metallizing coating (see A.17) and as an additive in other materials.
Copper materials are
generally grouped as follows:
-Commercially pure grades, of which there are many different "named" varieties that indicate the manufacturing method and the level of control of impurities, including oxygen.
-Alloys in which the alloying additions affect the metallurgical microstructure and consequently their characteristics (mechanical, electrical and thermal properties, environmental resistance). The main alloying addition generally provides the named classifications:
-brass: copper
- zinc alloys, often containing other alloying elements, such as lead which acts as a "lubricant" for machining operations - so-called "free-machining";
-bronze: copper - tin alloys, often containing other alloying elements.
Electronic assemblies use wires made of high-purity copper or copper alloy and terminals of copper alloy.
Beryllium-copper (also known as copper-beryllium) is a copper alloy with small additions of Be. Alloys form two groups: one with less than 1 %Be content and
the other with approximately 2 % Be. Cobalt and nickel additions (present for heat treatment purposes) tend to vary inversely with Be content. These alloys,
depending on their condition , offer combined mechanical performance and electrical conductivity for electrical and electronic applications (e.g. spring contacts); for low temperature applications; for high-strength corrosion resistant components and in safety applications in hazardous environments (no sparks produced when
impacted).
Copper is also used as a matrix phase in some reinforced metals. |
