| 摘要 |
PURPOSE:To reduce and stabilize the contact resistance while keeping the welding resistance, in a contact material to which a metal oxide generated by internal oxidation is dispersed into Ag, by making the metal oxide with a specified size hold a specified amount to the total metal oxide. CONSTITUTION:To stably keep the contact resistance 10mOMEGA or less, particle of a size of 1mum or less is required to be dispersed 90vol.% or more. To make the metal oxide particle of a size of 1mum or less disperse 90vol.% or more, Al and Mn is, for example, added into AgCd alloy. The size of the particle can be controlled depending on internal oxidation conditions, the internal oxidation temperature is kept low, the oxygen pressure of the internal oxidation is increased, and the oxidation time is also shortened. For example, by internally oxidizing a AgCd alloy (including 0.2% Fe) plate at 700 deg.C and 5 atmospheric pressure for one hour, a layer of approx. 50mum thickness into which CdO particle of one mum or less is dispersed can be obtained on the surface. As the metal oxide, not only CdO but also SnO2, In2O3, ZnO, or the like can be used. |
