Laser additive manufacturing of contact materials

Conventional production of contact materials employs several processing steps - partly in large scale - which could be distinctly reduced by using Additive Manufacturing (AM) techniques. In the present study, AM with contact materials of the systems Cu-Cr, Ag/WC and Ag/SnO2 in conventional compositions was investigated at the example of laser powder bed fusion (L-PBF) of metals. For powder preparation, spray drying and chemical precipitation were used. With decreasing mutual wettability of the components in the three systems Cu-Cr, Ag/WC and Ag/SnO2, the processing was found to be increasingly difficult. With the processing conditions used in this study, Cu-Cr and Ag/WC parts could be produced by L-PBF, resulting in 97% dense materials and consisting of the desired microstructure. However, homogeneous melting tracks could not be produced in Ag/SnO2 due to insufficient wettability. To the best knowledge of the authors this is the first study that proves the usability of L-PBF technologies for the production of materials with the same composition as it is used for contact materials. AM technologies allow contact pieces to be directly manufactured on the required Cu substrates, which allows the further reduction of steps in the processing chain.