Recent developments in the preparation of nano-gold composite coatings

Abstract

New possibilities in the design of gold-containing electrochemical coating systems for electronic applications are given by the incorporation of gold-nanoparticles in metal-matrix-systems. The major problem for the application of nanoparticles is the strong agglomeration of the particles in the electrolyte solutions, preventing the incorporation of nanoscaled dispersants. A complete new concept for the deposition of nano dispersion layers, overcoming this agglomeration challenge, is the application of core shell systems. Using these systems, it becomes possible for the first time to incorporate metal nanoparticles into electrodeposited metal layers to form metal nanoparticle metal matrix systems (MNP-MMS). The advantage of such layers is to form nanocomposite materials far away from the thermodynamic equilibrium. Especially for the combination of gold nanoparticles with a nickel matrix, a way is shown for the manufacturing of temperature-stable nanocomposite structures, because at least in the temperature range of electronic applications no loss of the dispersive character by diffusion processes is expected. By incorporating the precious metal material into the nickel matrix as the main electrodeposit, and reducing the top gold layer thickness, a possible way of reducing the gold consumption and an economic use of gold resources is shown.