Nanocrystalline Pd alloy films coated by electroless deposition.

The structures of palladium and palladium alloys thin films deposited from organic electrolytes onto metallic substrates by electroless plating method have been investigated. The coatings are dense, pore-free 0.005-1 microm thick films with high adhesive strength to the substrate surface. EDX, XRD, SEM and TEM methods were used to determine the composition and structure of alloy coatings of the following binary systems: Pd-Au, Pd-Ag, Pd-Ni, Pd-Pb, and ternary system Pd-Au-Ni. The coatings of Pd-Au, Pd-Ag and Pd-Ni have a solid solution structure, whereas Pd-Pb is intermetallic compound. It has been found that the deposited films consist of nanocrystalline grains with sizes in the range of 11-35 nm. Scanning and transmission electron microscopy investigations reveal the existence of clusters formed by nanocrystalline grains. The origin for the formation of nanocrystalline structures of coating films is discussed.