Copper-Nanolaminate Composites – a New and Promising Material for Electrical Contacts in High Voltage and High Current Applications

Nanolaminate M_n+1AX_n phases [1], [2] are materials that show interesting properties. They exhibit high hardness as well as good thermal and chemical stability, which is commonly a ceramic like behavior. On the other hand, they are good conducting materials near the range of metals.

Electrical contacts used in high voltage and high current applications are commonly based on silver-tin dioxid (Ag-SnO) where the SnO is used to increase the durability of the silver contact [3]. Futhermore the silver might be doped or alloyed with other materials such as tungsten or cadmium. The contact material is produced by powder metallurgical approach.

Lately the prices of noble metals are increasing and therefore, the pursuit of finding alternative possibilities is leading to new approaches and materials.

A promising approach is the electrochemical deposition of copper – nanolaminate composites. Two different types of M_n+1AX_n phase were chosen as hard particles. One was Ti₂AlC from the 211 M_n+1AX_n phase family and the second was Ti₃SiC₂ from the 312 M_n+1AX_n phase group. Particles of these two materials (mean size: aprox. 2 µm) were co-deposited with copper to form an electrical conductive surface with higher hardness than common copper. The distribution of the particles was determined using Focused Ion Beam cross section. The behavior at high currents and high voltages as well as in electrical discharges was investigated.

References:                                                       

[1]       M. W. Barsoum, “The MN+1AXN phases: A new class of solids,” Prog. Solid State Chem., vol. 28, no. 1–4, pp. 201–281, Jan. 2000.

[2]       R. Grieseler, T. Kups, M. Wilke, M. Hopfeld, and P. Schaaf, “Formation of Ti2AlN nanolaminate films by multilayer-deposition and subsequent rapid thermal annealing,” Mater. Lett., vol. 82, pp. 74–77, Sep. 2012.

[3]       N. Jeanvoine, C. Selzner, F. Soldera, and F. Muecklich, “In situ FIB-Surface Preparation of Ag/SnO Composites for EBSD Measurements,” Microsc. Microanal., vol. 13, no. S02, Aug. 2007.