Metal oxide on the surface of contacts having excellent contact performance

A model for the occurrence of contact failure by air pollution is proposed. Contacts of 99%Au-1%Ni and Pd were developed based on the hypothesis that some metal oxides have an effect on the preservation of contact performance against air pollution. Some experiments on the surface characteristics of 99%Au-1%Ni alloy, which support the verification of the model, are described. The experimental results are as follows: (1) nickel oxide accumulates on the surface of the 99%Au-1%Ni alloy; (2) the surface energy of polished 99%Au-1%Ni alloy in air decreases in a short time, but changes little even if nickel oxide accumulates on the surface; (3) in the case of the contacts of 99%Au-1%Ni and Pd, the low contact resistance state is maintained even if the nickel oxide accumulates on the surface; and (4) the dust particles produced by the successive operations of the contacts of 99%Au-1%Ni in contact with Pd are quite small (under 1 μm) and may be responsible for the contact failures