We report on the characterization of electroformed copper. Different copper films have been deposited, on a brass rod, paying attention to modify only one parameter of the galvanic bath for each specimen (acidity, temperature, density of current, etc.). The samples obtained have been analyzed by residual resistivity ratio (RRR) to evaluated the electrical conductivity, with the nanoindenter to measure the hardness and the reduced modulus and with the X-ray diffraction to calculate the average dimensions of the grains. The comparative analysis of all the data gives us the set of parameters required to obtain a good electrical conductor, working at cryogenic temperatures and mechanically resistant.Copper was one of the first metals historically used and its success is due to its unique properties: 1 i. toughness; ii. ductility; iii. resistance to many corrosive environments; iv. high electrical conductivity and v. high thermal conductivity. The use of copper is widespread not only as pure metal, but also entering in alloys with various others metals, preserving good mechanical characteristics down to low temperatures. From the environmental point of view, copper is the less dangerous metal if compared to other metals used in the deposition processes. 1 Also the recycling treatments are well known and this helps to find the most suitable solutions for managing the handling of galvanic products and disposal of residuals linked to the electroplating activities. Compared to other metals, copper is one of the most used in the deposition processes. 2 Copper is an excellent substrate, when is mechanically polished, and its electrical conductivity, being second only to silver, makes it an excellent and inexpensive coating for printed circuit boards. 2 Furthermore it is suitable for covering surface defects like holes or splinters and it is used as an excellent buffer layer between the substrates and the subsequent deposits. The large use of Cu in electrical industry is mainly due to the possibility to deposit this material with different techniques. Among them, the electro-deposition method assures fast and low-cost depositions combined with a great repeatability. In addition to the huge number of applications, its good electrical properties -which improve at low temperature -make it one of the most used material in the electrical wire industry; in particular cases it can be coupled with brass (characterized by a lower thermal conductivity) and used in specific applications such as electrical connectors for high current superconducting devices. A thick film of copper on a brass support is often used for obtaining special current leads, with selected balancing at cryogenic temperatures between electrical resistance and total thermal conductivity between room temperature and cryogenic bath. 1,2,3 In this way it is possible to supply the required high currents, also minimizing the heat absorbed by the external environment and by the instrumentation from the cryogenic line. The use of brass, as internal support of a copper con...

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