The reliability and electrical life of contact systems in switching devices as wellas in electromechanical and electronic components do not only depend on thecontact material. The selection of the most suitable carrier material also playsan important role.

The most frequently used ones are copper based materials. Depending on theapplication also materials based on nickel or multi-layer composite materials,such as thermo bimetals for example, are frequently used. For specialapplications in the medium and high voltage technology, as well as for springsand snap discs for the information technology, iron or steel based materials areconsidered. These are however not included for the purpose of this data book.

Various requirements based on the enduse of the contact components have tobe met by carrier materials. Copper materials have to exhibit high electrical andthermal conductivity, good mechanical strength even at elevated temperatures,and in addition a sufficient high resistance against corrosion. If used as springsthe carrier materials also must have good elastic spring properties. Besidesthese, the materials must, depending on the manufacturing processesemployed, also have good technological properties like ductility to allow warmand cold forming, suitability for cutting and stamping, and be capable to bewelded, brazed or coated by electroplating.

Copper and copper alloys to be used in electrical and electronic componentsare usually covered by national and international standards. DIN numbers thematerials by a prefix and/or a material number. The newer European standards(EN) refer to the material's usage products and also show a prefix and materialnumber. For reference we also show in <xr id="tab:tab5.1"/> the material designationaccording to UNS, the Unified Numbering System (USA). Other internationallyused standard and material numbers include, among others, those issued byCDA (Copper Development Association, USA), and GB (Guo Biao – China).

The most important EN as well as the US based and widely used ASTMstandards covering the use of flat rolled copper and copper alloys in electricalcontacts are: