Copper is an important raw material in modern industry. The rapid development of emerging industries such as new energy and electronic information has led to an increasing demand for high-performance copper powder. Among these, micro and nano copper powder stands out in particular. Due to its high electrical and thermal conductivity, low electrochemical migration, and strong weldability, micro and nano copper powder has become an important functional material in many fields such as modern military, shipbuilding, aerospace, and high-end technology.

Micro and nano copper powder refers to materials with dimensions ranging from micrometers (1–100 μm) to nanometers (10–100 nm). Due to its small size and unique, superior properties, micro and nano copper powder holds great promise for development in numerous fields, including electronic pastes, catalysis, medical antibacterial applications, and lubricant additives.

There are two methods for preparing micro and nano copper powder: physical and chemical methods. The physical method is an early technique for preparing micro and nano copper powder, which involves using external forces or physical changes to convert metallic copper into nano-sized powder. This method primarily includes high-energy ball milling, mechanical grinding, physical vapor deposition (PVD), and electro-explosion methods. The chemical method refers to the process of producing micro and nano copper powder by reacting copper precursors in ionic form with reducing agents in a solvent, or by directly thermally decomposing the precursors, primarily including electrolysis, microemulsion, sol-gel, hydrothermal, and liquid-phase reduction methods.

Although physical methods are cost-effective and scalable, they still have significant drawbacks. First, impurities can easily contaminate the nano powder during preparation, resulting in low purity. Additionally, when particle sizes are at the nano-scale, the factors influencing particle size control become more complex, leading to higher requirements for process parameters and increased energy consumption. The quality of micro and nano copper powder produced by physical methods is relatively poor, and their production volume is also low. More importantly, physical methods cannot control the particle size distribution or morphology of the produced micro and nano copper powders, failing to meet the increasingly diverse and high-standard demands for micro and nano copper powder.

Currently, the liquid phase reduction method is the most commonly used and most industrially promising preparation method. It utilizes redox reaction mechanisms, where reactants undergo chemical reactions under the influence of a reducing agent in a liquid phase or near-liquid phase environment, producing micro and nano particles. The particle size and morphology of nano copper particles can be controlled by adjusting reaction conditions. This method features a simple operational process, with the resulting nano particles exhibiting easily controllable morphology and particle size, and is environmentally friendly, making it highly promising for practical applications.

As downstream industries develop and application areas expand, the global market for ultra fine copper powder will maintain a high growth trend. In the future, the large-scale application of micro and nano copper powder will still need to address the following key issues: 

1. Production process costs, the antioxidant properties, anti-agglomeration properties, and dispersibility of copper powder. 

2. Although the liquid phase reduction method can produce high-purity nano copper powder, it is necessary to address the key technical issues associated with the scaling-up effect. 

3. Utilizing surface modification techniques to achieve oxidation resistance and anti-agglomeration. 

4. To ensure that the prepared copper powder can form conductive films or other materials, it is necessary to address dispersion issues in different media, enabling the copper powder to achieve uniform dispersion in solvents across various application environments (such as conductive pastes and lubricant additives).