Method for Polishing Conductive Metal Surfaces

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This patent discloses an improved electrochemical method for polishing conductive metal surfaces (such as gold, platinum, copper alloys, and specific coatings) by immersing the metal (as anode) in an ammonium nitrate and ammonium chloride electrolyte, applying controlled non-plasma-forming voltages. The method achieves a very low surface roughness and a shiny appearance without using hazardous chemicals or requiring high power, distinguishing it from conventional electropolishing and plasma polishing techniques.

Use CasesContent extracted from patent full text and abstract with AI.

• Polishing of precious metal jewelry (e.g., gold, platinum) for a high-gloss finish.
• Surface finishing of electronic components that use conductive metals for optimal electrical properties.
• Preparation of surgical and dental instruments made of metals for smooth, sanitary surfaces.
• Polishing and deburring precision parts in watchmaking and micro-mechanical devices.
• Removing and finishing hard surface coatings (e.g., TiAlN, AlCrN) on tools, such as drill bits, without damaging the substrate.
• Restoration or finishing of collectibles and artifacts made from precious metals or copper alloys.
• Industrial deburring and smoothing of complex-shaped conductive metal parts.

BenefitsContent extracted from patent full text and abstract with AI.

• Achieves exceptionally low surface roughness levels (Rₐ < 0.03 μm), resulting in highly smooth and shiny surfaces.
• Utilizes non-hazardous, environmentally friendly electrolytes, improving workplace safety and reducing environmental impact compared to conventional methods.
• Operates below plasma thresholds, significantly lowering power consumption and reducing the risk of electrical hazards.
• Compatible with various metals and metal alloys, as well as coated surfaces, widening its applicability.
• Capable of treating complex and structured surfaces effectively, unlike traditional mechanical polishing.
• Results in minimal and controlled material loss, crucial for applications with precious metals and fine details.
• Faster processing times compared to many existing polishing methods, increasing manufacturing efficiency.
• No need for hazardous acids or corrosive salts common in traditional electropolishing, simplifying handling and waste management.

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Inventors & Applicants

Patent Abstract

A method for polishing a conductive metal surface is provided. The method comprises the steps of a) providing an electrolyte comprising ammonium nitrate and ammonium chloride, b) connecting a first electrode to the conductive metal surface and connecting a second electrode to the electrolyte, wherein said conductive metal surface is the anode. Then, a gas phase surrounding the conductive metal surface is generated. This step comprises in no particular order a first voltage step and an immersion step. The first voltage step comprises applying a first electrical voltage to the first and second electrode, wherein this first electrical voltage is suitable for generating the gas phase. The immersion step comprises contacting the conductive metal surface with the electrolyte. Then, a second electrical voltage is applied and maintained for a period of at least 1 second.