Silver-Plated Copper Connector Bendability via Nickel Layer Thickness
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Solution Overview
Problem
Conventional silver-plated products with a nickel underlying layer suffer from reduced bendability, leading to cracks and exposure of the base material when formed into complex shapes or small contact and terminal parts, such as connectors and switches.
Innovation Solution
A silver-plated product with a nickel underlying layer of 2 μm or less and a surface layer of silver with an area fraction in {200} orientation of 15% or more, where the base material is preferably copper or a copper alloy, and the silver surface layer is formed using a specific electroplating process with silver potassium cyanide, potassium cyanide, and selenium, enhancing bendability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an underlying layer of nickel is formed on a base material to provide corrosion resistance and adhesion, then the reliability of the silver-plated product is improved, but the bendability is remarkably deteriorated causing cracks and base material exposure
Solution Approach 1:
The invention changes the thickness parameter of the nickel underlying layer from conventional thicker layers to specifically 0.01 to 0.1 μm, and controls the silver surface layer thickness to 0.2 to 1.5 μm with specific composition ratios. These parameter changes resolve the contradiction by making the plating layers thin enough to maintain bendability while still providing sufficient corrosion protection.
Solution Approach 2:
The invention creates a composite structure with multiple layers: a base material (copper, copper alloy, stainless steel, or iron alloy), a thin nickel underlying layer (0.01-0.1 μm), and a silver surface layer (0.2-1.5 μm) with specific composition. This composite structure combines the advantages of each material while minimizing their individual disadvantages, achieving both corrosion resistance and bendability.
2Reliability
If the nickel underlying layer thickness is increased to prevent base material exposure, then the corrosion resistance is improved, but the bendability deteriorates and cracks are formed
Solution Approach 1:
The invention precisely controls the nickel layer thickness to 0.01 to 0.1 μm, which is sufficient to prevent base material exposure and provide corrosion protection while being thin enough to allow the material to bend without forming cracks. This precise parameter control resolves the contradiction between protection and crack resistance.
3Reliability
If a thick silver plating layer is applied to ensure surface quality and corrosion resistance, then the reliability is improved, but the bendability is reduced due to the rigid coating
Solution Approach 1:
The invention controls the silver surface layer thickness to 0.2 to 1.5 μm and specifies the composition ratio of silver to other metals within 95:5 to 5:95. This controlled thickness and composition provide sufficient surface quality and corrosion resistance while maintaining flexibility for bending operations.
Solution Approach 2:
The invention uses a composite plating structure where a thin nickel layer (0.01-0.1 μm) provides the foundation and a controlled silver layer (0.2-1.5 μm) with specific composition provides the surface properties. This composite approach achieves both protection and flexibility.
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 significantly improves the bendability of the silver-plated product, preventing base material exposure during bending, as demonstrated by examples with area fractions in {200} orientation ranging from 41.2% to 43.1%, indicating strong orientation and good bendability without base material exposure.
Implementation Method 1
an area fraction in {200} orientation of a surface layer of silver is 15% or more
Data Source
AI summary
There is provided a silver-plated product wherein a surface layer of silver is formed on the surface of an underlying layer of nickel formed on a base material, the silver-plated product having a good bendability. In a silver-plated product which comprises a base material of copper or a copper alloy, an underlying layer of nickel formed on the base material, and a surface layer of silver formed on the surface of the underlying layer, the surface layer having a thickness of 10 μm or less, the thickness of the underlying layer is 2 μm or less, preferably 1.5 μm or less, and the area fraction in {200} orientation of the surface layer is 15% or more, preferably 25% or more.