Silver-Carbon Composite Plating to Reduce Particle Dropout

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Solution Overview

Problem

Conventional composite plated products for sliding contact parts, such as switches and connectors, face issues with high coefficients of friction and wear resistance, leading to carbon particle dropout during press-work, which can cause short-circuits and contamination, and require additional silver-plating steps increasing costs.

Innovation Solution

A method involving electroplating a base material with a silver-plating solution containing carbon particles, followed by a surface treatment such as ultrasonic or electrolytic cleaning to remove part of the carbon particles, resulting in a composite plating film with reduced carbon particle dropout and improved wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If carbon particles are added to silver-plating solution to form composite plating film, then wear resistance is improved, but carbon particles drop out during press-work causing contamination and short-circuits

Engineering Contradiction:
Improvewear resistanceVSAvoidcarbon particle dropout
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by performing surface treatment (such as cyanide treatment or oxidation treatment) on the composite plating film after electroplating but before use. This treatment creates a conversion layer on the surface that bonds carbon particles more securely to the silver matrix, preventing their dropout during subsequent press-work operations while maintaining the wear-resistant properties of the composite structure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes composite materials by creating a multi-layered plating film consisting of a silver matrix with embedded carbon particles, where the silver provides ductility and electrical conductivity while carbon particles provide wear resistance. The surface treatment further creates a composite conversion layer that secures the carbon particles, resolving the contradiction between maintaining particle integrity and preventing dropout

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If carbon particles are added to silver-plating solution, then lubricity is improved, but coefficient of friction increases making it unsuitable for long-life contacts

Engineering Contradiction:
ImprovelubricityVSAvoidcoefficient of friction
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent applies local quality by creating a surface treatment layer with different properties from the bulk composite plating film. The surface treatment (cyanide or oxidation treatment) creates a conversion layer that has lower friction characteristics than the untreated carbon-silver composite, providing low friction at the contact surface while maintaining the lubricity benefits of carbon particles in the bulk material

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the chemical and physical parameters of the plating film surface through surface treatment. The treatment modifies the surface composition and structure, creating a conversion layer with optimized friction characteristics that enables the material to achieve both good lubricity from carbon particles and low coefficient of friction for long-life contact applications

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional silver-plating step is performed to prevent carbon particle dropout, then particle retention is improved, but manufacturing cost increases

Engineering Contradiction:
Improveparticle retentionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent performs surface treatment as a preliminary action immediately after electroplating, which secures carbon particles to the plating film before any potential dropout can occur during manufacturing or use. This single surface treatment step replaces the need for additional silver-plating steps, achieving particle retention while simplifying the manufacturing process and reducing costs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the essential function of securing carbon particles from the complex multi-step process of electroplating followed by additional silver-plating. By isolating and applying a specific surface treatment (cyanide or oxidation treatment) as a standalone step, the patent achieves particle retention without requiring redundant plating operations, thereby reducing manufacturing complexity and cost

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method produces a composite plated product with a lower coefficient of friction and enhanced wear resistance, reducing the risk of carbon particle contamination and maintaining the integrity of the plating film, while minimizing the amount of carbon particles dropped out, thus ensuring reliable performance in sliding contact applications.

Implementation Method 1

forming a composite plating film of a composite material, which contains the carbon particles in a silver layer, on a base material by electroplating the base material using the silver-plating solution containing the carbon particles

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 2

a treatment for ultrasonic cleaning or electrolytic cleaning the surface of the composite plating film

Methodology Applied
Scientific EffectUltrasonic cleaning: Ultrasonic Vibration

Implementation Method 3

a treatment for ultrasonic cleaning or electrolytic cleaning the surface of the composite plating film

Methodology Applied
Scientific EffectElectrolytic cleaning: Electrolysis

Data Source

PatentUS11920255B2Composite plated product and method for producing same
Publication Date: 2024.03.05 DOWA METALTECH CO LTD

AI summary

There are provided a composite plated product wherein a composite plating film of a composite material containing carbon particles in a silver layer is formed on a base material and wherein the amount of the carbon particles dropped out of the composite plating film is small, and a method for producing the same. After a composite plating film of a composite material containing carbon particles in a silver layer is formed on a base material (of preferably copper or a copper alloy) by electroplating using a silver-plating solution to which the carbon particles are added, a treatment for removing part of the carbon particles on the surface thereof is carried out.