| 摘要 |
<p>PURPOSE:To easily recover the exposed portion of the ground Au plated layer of the Rh plated of electric contact piece by using a two-layered liquid consisting of an Au-dissolving liquid and a water-insoluble organic solvent having a great specific gravity. CONSTITUTION:In the manufacture of an electric contact piece, e.g., switch, etc., a Rh plated layer 4 is formed on the ground Au plated layer 3 of the contact portion of the contact piece 1. In order to recover the exposed portion of the ground Au plated layer 3 on the Rh plated layer, the contact piece 1 is dipped in a two-layered liquid consisting of an upper liquid layer 10 containing potassium iodide or a cyanide capable of dissolving Au and a lower organic solvent layer 9 containing Fleon or trichlorethane having a great specific gravity and insoluble in water. In this case, the Rh plated layer and its slightly upper portion are dipped in the organic solvent layer 9, the exposed portion of the ground Au plated layer is dipped in the liquid layer 10, and Au is therefore dissolved, removed, and recovered in the form of a complex in the liquid layer 10.</p> |
