| 摘要 |
PURPOSE:To obtain a superior electropolishing soln. for gold and gold alloys without using a virulently poisonous cyanogen compound by dissolving a specified ord. acid, the Na salt of an org. acid and an org. additive in water. CONSTITUTION:When an accessory of pure gold, 18-karat gold, 14-karat gold, an Au-Cu alloy, an Au-Ag alloy, an Au-Ag-Cu alloy or the like having a complex shape is electropolished, an aqueous soln. contg. 5wt% each of an org. acid such as sulfamic acid, the Na salt of an org. acid such as sodium tartrate or sodium oxalate and an org. additive such as thiourea is used at 70-80 deg.C as an electropolishing soln. The gold or gold alloy accessory is electropolished as the anode at 80A/dm<2> anode current density for about 4min electrolysis time. Since the electropolishing soln. contains no poisonous cyanogen compound, produced effluent can be made harmless by neutralization or other method before discharge.
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