New technology of silvering aluminium busbar joints with the use of printable paste containing nano-size Ag particles

Aluminium silvering is widely used for creating high current joints between two busbar connectors to transfer electrical power. Silver properties improved joints quality and long term conductivity. The most commonly used technique is the laborious electroplating, which produces a lot of toxic sludges. As an alternative, the authors elaborated new technology of silvering busbar connectors. The new method of aluminium silvering consists of well-known screen printing process of properly prepared paste with silver nanoparticles. Use of nanoparticles gives an opportunity to print and sinter the silver layer on aluminium base. Another advantage of this technology is that the layer can be deposited and sintered in outdoor conditions, using acetylene torch or hot air gun. In this paper, several technological parameters, as well as obtained results, are discussed. Different paste compositions, grain size of silver nanoparticles and sintering method were measured. The adhesion between silver layer and aluminium base was measured. The contact resistivity of joints between silvered electrodes were tested and compared to electroplated joints or pure aluminium contacts. The measurements results are shown and discuss. The screen printed layer was less dependent on joint pressure than those from pure or electroplated aluminium.