Electroplated Copper Alloy Layers for Corrosion Resistance

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Solution Overview

Problem

The fashion and jewelry industries face challenges in achieving non-allergenic, economically viable, and environmentally friendly electroplated products with high corrosion and abrasion resistance, as existing solutions often rely on nickel or palladium intermediate layers that are costly or pose health risks.

Innovation Solution

An electroplated product with multiple copper alloy layers, specifically a first copper alloy with lower copper concentration and a second with higher copper concentration, acts as a copper sink to prevent migration, eliminating the need for nickel or palladium, and featuring a precious metal finishing layer for improved durability and brightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nickel or palladium intermediate layers are used to prevent copper migration and provide corrosion resistance, then corrosion resistance is improved, but production cost increases and allergenic risks arise

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the intermediate layer into two distinct copper alloy layers with different compositions: a first copper alloy layer (lower copper concentration, higher tin and zinc) adjacent to the base material, and a second copper alloy layer (higher copper concentration, lower tin and zinc) adjacent to the precious metal finishing layer. This segmentation allows each layer to perform specialized functions - the first layer acts as a copper sink to prevent copper migration, while the second layer provides corrosion resistance and brightness, thereby eliminating the need for expensive nickel or palladium intermediate layers.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If white bronze (copper, tin, zinc alloy) is used as an alternative to nickel, then nickel-free production is achieved, but corrosion resistance requirements are not met

Engineering Contradiction:
Improvenickel-free productionVSAvoidcorrosion resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent creates a composite structure using two different copper alloy layers with distinct compositions. The first copper alloy layer contains lower copper concentration (e.g., 60-80 wt% Cu) and higher tin and zinc content, while the second copper alloy layer contains higher copper concentration (e.g., 80-95 wt% Cu) and lower tin and zinc content. This composite arrangement combines the copper-sink capability of the tin-rich first layer with the corrosion resistance and brightness of the copper-rich second layer, achieving both nickel-free production and superior corrosion resistance.

Inventive Principle:
Principle #40Composite materials

3Illumination intensity

If tin content is increased to more than 50 wt.-% to improve brightness, then brightness level increases, but resistance to acidity and oxidants decreases leading to poor corrosion resistance

Engineering Contradiction:
Improvebrightness levelVSAvoidcorrosion resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies local quality by creating spatial variation in alloy composition across the intermediate layers. The first copper alloy layer has lower copper concentration and higher tin content optimized for copper migration prevention, while the second copper alloy layer has higher copper concentration and lower tin content optimized for corrosion resistance and brightness. This local differentiation allows each region to possess the specific properties needed for its function, avoiding the need for uniformly high tin content that would compromise corrosion resistance.

Inventive Principle:
Principle #3Local quality

4Reliability

If chromium intermediate layers are used, then adhesion and corrosion resistance are improved, but toxic chromium VI is used and adhesion problems occur

Engineering Contradiction:
Improveadhesion and corrosion resistanceVSAvoidtoxicity and adhesion problems
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive and toxic chromium intermediate layers with environmentally friendly copper alloy layers that are both effective and economical. The two-layer copper alloy structure provides the necessary adhesion and corrosion resistance without relying on toxic chromium VI, thereby eliminating harmful factors while maintaining protective functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution provides enhanced corrosion and abrasion resistance, increased shelf life, and reduced production costs, while ensuring the product is non-allergenic and meets the brightness requirements of the fashion industry.

Implementation Method 1

The electroplated product comprises a base material, a first electroplated copper alloy layer, a second electroplated copper alloy layer, and a precious metal finishing layer

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 2

the second copper alloy layer acts as a copper sink and prevents migration of copper into the precious metal finishing layer

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentEP3312309B1Electroplated product having a precious metal finishing layer and improved corrosion resistance, method for its production and uses thereof
Publication Date: 2020.04.29 COVENTYA SRL
  • EP3312309B1 patent drawingFigure 1A~1B
  • EP3312309B1 patent drawingFigure 2A~2B
  • EP3312309B1 patent drawingFigure 3A~3B

AI summary

This invention provides an electroplated product with a precious metal finishing layer that has an improved corrosion and abrasion resistance. The electroplated product comprises two electroplated copper alloy layers having a different copper concentration (e.g. white bronze and yellow bronze). The electroplated product is especially suitable for use in jewelry, fashion, leather, watch, eyewear, trinkets and/or lock industry. Another advantage of the electroplated product is that the use of allergenic nickel or expensive palladium intermediate layers against copper migration can be dispensed with. This means that the electroplated product can be non-allergenic (nickel-free) and be provided in a more economical and environment-friendly manner. A method for the production of the inventive electroplated product is presented. Furthermore, the use of the inventive electroplated product in the jewelry, fashion, leather, watch, eyewear, trinkets and/or lock industry is suggested.