Low-Temperature Sintering to Form Copper Electrodes Nano Copper Powder

Customer Requirements
The need for copper powder that disperses uniformly, resists agglomeration, and can be formed into thin copper electrode films.
The need for copper powder that achieves conductivity after sintering at low temperatures.
The need for a way to lower the sintering temperature of the copper powder already in use.
The need for copper powder that resists oxidation even when exposed to air.
The need for copper powder that sinters at below 300°C as a substitute for silver powder, but not one that oxidizes readily.

Energy-efficiency mandates, the proliferation of electric vehicles, and ongoing innovation in electronics manufacturing are expanding and diversifying demand for copper-based conductive materials.

Could the distinctive properties of our copper powder address these challenges?
Sumitomo Metal Mining has developed an oxidation-resistant nano copper powder, the UCP series, with a finer and narrower particle size distribution than conventional atomized copper powders.
The UCP series is designed for low-temperature sintering (below 250°C) and improved oxidation resistance, easing the oxidation-related constraints usually associated with finer copper particles.

Sintering bonds particles into a solid mass through heat, pressure, or both, without fully melting them. Higher temperatures generally accelerate sintering, while the densification rate varies with powder characteristics such as particle size, shape, and surface condition.

Copper-based materials are promising candidates for low-temperature sintering, but copper oxidizes more readily than silver, and the problem only worsens as particles are made finer to improve sinterability. Engineering particle surfaces to limit oxidation without inhibiting sintering is therefore essential.

Our oxidation-resistant nano copper powder, the UCP series, combines low-temperature sintering with oxidation resistance. At submicron size, it falls within the ultrafine powder class.

Low-Temperature Sinterability

Compared with general atomized copper powder, the UCP series has a finer, narrower particle size distribution. It can be used on its own as a conductive powder or blended with larger-particle copper powders as a sintering additive to reduce the overall sintering temperature.

Oxidation Resistance

Since the antioxidant coating bonds directly to the copper surface without an oxide layer in between, the powder does not easily oxidize, even when exposed to air at room temperature. That makes it easy to handle, and it holds up well as a conductive filler in pastes and inks.

Oxidation-Resistant Nano Copper Powder (UCP series)

Adjusting the mixing ratio of the UCP series tunes sintering behavior to different processing requirements. Because the UCP series is submicron (ultrafine) and oxidation-resistant, sintering starts at temperatures around 200°C, and the powder can also serve as a sintering additive for atomized copper powders of larger particle size.

The figure shows the volume change rate of our oxidation-resistant nano copper powder, UCP series, during heating in a reducing atmosphere.

Copper's low electrical resistance and excellent thermal conductivity make it applicable across a wide range of electronic components, and in recent years its antibacterial properties have drawn attention as well. Our oxidation-resistant nano copper powder features a narrow particle size distribution and can be handled in air without difficulty. These characteristics (oxidation resistance and antibacterial properties) can be applied in many other fields. Explore the possibilities of our oxidation-resistant nano copper powder for your field, and bring your ideas to life together with us.