| 摘要 |
<p>The parent patent describes elements for electrical contacts subject to rubbing, with oxide particles enrobed in a thin surface layer. As the foundation metal for the elements a good conductor such as silver or copper is used, to which a small proportion of a more readily oxidisable material is added. The element is then oxidised by heat to give a contact standing up well to wear, esp. by the elimination of the microwelding effect, without it being necessary to have an alloy as a basis with a much higher resistance than copper or silver. In this addn. the technique consists in forming the element of the desired conducting metal without having regard to the oxide particles necessary. The element is then coated electrolytically at least over its working surface area, as regards the flow of the current, with a layer of the metal of the foundation in which the particles are made to appear. As the metal of the base is being deposited, a very small amt. of an additional metal which is more readily oxidisable is mixed in simultaneously. The element coated in this way is treated thermically so as to produce the phenomenon of internal oxidation described in the parent patent. Oxide particles may be incorporated in the surface layer by maintaining such particles in suspension in the bath during depositing. Avoids the necessity of having to add to the foundation metal any material which would alter the characteristics and esp. the resistance desired for the intended application.</p> |
