FUKUDA has developed flake copper powder for electronic materials.
In Wiring Formation
Traditionally, silver has been mainly used in the field where metal paste is applied and printed and then fired to form conductive circuits.
However, in recent years, copper has been attracting attention due to rising raw material costs and concerns about environmental impact.
In the field of printed electronics, where conductive circuits are directly printed onto substrates, active technological research is underway using nano- and submicron-sized particles.
During firing, particle aggregation occurs as the coated films shrink. In such cases, when using spherical or granular nanoparticles, the resulting films are prone to decreased conductivity, reduced adhesion, and insufficient mechanical strength.
New Proposal from FUKUDA
FUKUDA proposes ultra thin flake copper powder as a solution to these problems.
FUKUDA's ultra thin flake copper series offers high conductivity and coating film strength.
The use of ultra thin flake copper powder not only improves properties such as conductivity, but also contributes to reducing environmental impact.
Advantages of Using Ultra Thin Flake Copper Powder
With spherical or granular fine copper powder, cracks easily occur due to film shrinkage during firing, making it difficult to obtain adhesion strength and conductivity with the substrate.
Ultra thin flake copper powder allows the coated film to shrink in the plane direction (horizontal direction in the figure), reducing the risk of breaking and thereby enhancing adhesion strength and conductivity.
Image of Conductive Film Cross Section
*Image of Comparison Using our Materials
Product Lineup
Ultra Thin Flake Copper series [nanoThin]
Powder Properties
| Flake Copper Powder | 50%-Diameter | BET Specific Surface Area |
Apparent Density | Fat Content |
|---|---|---|---|---|
| （μm） | （m2/g） | （g/cm3） | （％） | |
| CuX-4 | 3.8 | 2.4 | 0.9 | 1.8 |
| CuX-5N | 4.0 | 2.9 | 0.7 | 0.5 |
| CuX-6N | 6.2 | 2.2 | 0.7 | 0.4 |
| CuX-6 | 6.3 | 2.1 | 0.8 | 1.2 |
| CuX-7 | 7.0 | 2.1 | 0.7 | 0.7 |
*All data and figures shown above are typical values and are not guaranteed. All content is subject to change without advance notice.
SEM Image
CuX-5N×5000
CuX-6×5000
Conductivity Data
Example of Volume Resistivity of Conductive Film
| Flake Copper Powder | 50%-Diameter | BET Specific Surface Area |
Apparent Density | Processing Temperature | Volume Resistivity |
|---|---|---|---|---|---|
| （μm） | （m2/g） | （g/cm3） | （°C） | (Ω・cm) | |
| CuX-4 | 3.8 | 2.4 | 0.9 | 275 | 3.3×10-5 |
| 300 | 2.9×10-5 | ||||
| CuX-5N | 4.0 | 2.9 | 0.7 | 275 | 5.6×10-5 |
| 300 | 3.2×10-5 | ||||
| CuX-6N | 6.2 | 2.2 | 0.7 | 275 | 7.3×10-5 |
| 300 | 5.8×10-5 | ||||
| CuX-6 | 6.3 | 2.1 | 0.8 | 275 | 5.0×10-5 |
| 300 | 3.5×10-5 | ||||
| CuX-7 | 7.0 | 2.1 | 0.7 | 275 | 5.5×10-5 |
| 300 | 4.0×10-5 |
*All data and figures shown above are typical values and are not guaranteed. All content is subject to change without advance notice.
Fabrication Conditions for Conductive Films
Substrate:Microscope Slide
Paste: Flake Copper Powder + Resin + Solvent *Copper Content After Curing = 90 wt%
Firing Atmosphere: 100% Nitrogen
Firing Time: 60 min
Forming Temperature: 275°C and 300°C
Film Thickness: Approx. 10-20 μm
Volume resistivity of each product
Example: Conductive Film After Firing
Cross-Sectional SEM of Conductor Film
Cross Section of CuX-4 use (Fired at 300°C) ×5000
Other Uses and Advantages
For example, although the average particle size of CuX-5 is approximately 4 μm, its extremely thin flake-like morphology results in a sphere-equivalent particle size of 228nm (based on the BET specific surface area). This gives a specific surface area equivalent to that of submicron-order particles. Therefore, it holds potential for catalytic and antimicrobial applications.
Sem Image
Particle Size Direction
Thickness Direction
Main Properties (typical values)
| Item | Properties |
|---|---|
| Shape | Ultra Thin Flake Copper |
| 50%-Diameter（μm） *1 | 4.0 |
| Thickness (nm) *2 | 80 |
| Aspect Ratio *3 | 50 |
| BET Specific Surface Area （m2/g） | 2.9 |
| BET Diameter (nm) *4 | 228 |
*1.50%-Diameter = Value of laser particle size distribution measurement
*2.Thickness = Calculated value estimated from BET specific surface area value
*3.Aspect ratio = 50%-Diameter/thickness
*4.BET Diameter = Particle diameter calculated in sphere equivalent from BET specific surface area value
*All data and figures shown above are typical values and are not guaranteed. All content is subject to change without advance notice.
Inquiries and requests for small samples are welcome.