Flake-Form Conductive Filler Uniform Silver Coating
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Solution Overview
Problem
The existing silver-coated copper fillers face issues with non-uniform silver coating, leading to reduced conductivity and temporal stability due to exposed copper surfaces, and require lengthy preparation processes for conductive powder mixtures, while achieving high conductivity and oxidation resistance remains challenging.
Innovation Solution
A flake-form conductive filler is produced by silver-coating copper-containing powder through electroless plating and subsequent flaking in an organic solvent with a spherical grinding medium, ensuring a uniform silver coating over the entire surface, which enhances conductivity and oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive powder mixture of scaly particles and spherical particles is used to increase filling density, then conductivity is improved, but preparation time and effort increase significantly
Solution Approach 1:
The patent merges the functions of scaly particles and spherical particles into a single flake-form filler that combines both shape characteristics. This unified particle design achieves high filling density and good conductivity without requiring separate preparation, blending, and formulation steps for different particle types, thereby significantly reducing preparation time and effort.
Solution Approach 2:
The flake-form conductive filler serves multiple functions simultaneously: it provides high filling density like scaly particles, good conductivity like spherical particles, and ease of processing. This multi-functional particle design eliminates the need for complex multi-step preparation processes while maintaining or improving electrical performance.
2Shape
If copper powder is made thinner and scaly to achieve smooth conductive coating, then surface smoothness is improved, but specific surface area increases making dispersion difficult and plating uniformity impaired
Solution Approach 1:
The patent changes the particle morphology from thin scaly form to flake-form with controlled aspect ratio. This parameter change in shape characteristics maintains surface smoothness for good conductive coating while reducing specific surface area to improve dispersion in reaction solution, thereby ensuring uniform plating and stable production.
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 flake-form conductive filler offers improved conductivity and stability, simplifying production and eliminating the need for blending different shaped fillers, resulting in a cost-effective and efficient conductive paste composition with enhanced temporal stability.
Implementation Method 1
a silver coating formed on the surface of copper-containing powder
Implementation Method 2
flaking in an organic solvent with a spherical grinding medium
Data Source
AI summary
The present invention provides a flake-form conductive filler which is easy and low-cost to produce and has a high conductivity. The flake-form conductive filler of the present invention includes a flake-form base material and a silver coating covering the entire surface of the flake-form base material. The flake-form base material contains copper. The flake-form conductive filler has a ratio a/b between a peak intensity "a" derived from a silver (111) plane and a peak intensity "b" derived from a silver (220) plane at 2 or less in the powder X-ray diffraction measurement.