Electrodeposition of amorphous Au–Ni alloy film

It was found that, by choosing an optimum bath composition, amorphous Au–Ni alloy containing up to 40 at.% of Au with respect to the sum of Au and Ni can be electrodeposited from a bath prepared by excluding tungsten from the Au–Ni–W bath that we developed previously. Elemental analysis showed that the deposit contains 15–20 at.% of carbon and 2 at.% of nitrogen. Hardness of this deposit is almost three times as high as that of the conventional hard gold. The electrical contact resistance measured against a pure gold wire is comparable to that of the hard gold. The amorphous structure of the Au–Ni deposit is stable at temperatures up to 300 °C for at least 1 h. The amorphous tungsten-free Au–Ni deposit is worthy of consideration for applications in the fabrication of micro- and nano-scale electrical contacts.