Fabrication of Au/Cu graded bimetallic alloy coating with DC magnetron sputtering

Au/Cu bimetallic alloy coatings were prepared by direct current (DC) magnetron sputtering on the surfaces of Si substrates and glow discharge polymer (GDP) microspheres. The compositions of Au and Cu in Au/Cu alloy coating were controlled by tuning the sputtering power of Au target and Cu target during the sputtering process. Scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) were used to examine the structure, roughness, density and composition of the coatings. The results indicate that the compositions of Au and Cu change nearly linearly with the increase of the coating thickness. The surface roughness of the coating is good and the thicknesses of all the coatings are almost the same. The coating shows highly packed microstructures, with no interspaces between different grains. (authors)