Preparation technology of ultrafine copper powder

With higher surface activity and good electrical conductivity and thermal conductivity, it is an important industrial raw material for quantity. In recent years, there were many reports about preparation of ultrafine copper powder, such as gas vapor extraction, the gamma ray method, plasma method, mechanical, chemical method and liquid phase reduction method. In general, it can be divided into physical and chemical methods.

The gas vapor extraction is the preparation of metal ultrafine powders is the most direct and effective method of preparation of a copper vapor steam with improved legal system powder technology ultrafine powders, the yield of 0.5kg / h. The induction heating method is served in a ceramic crucible, the metal material in the high or intermediate frequency current sensing by self-heating and evaporation, this heating method with a strong induction stirring, fast heating, high temperature. The structure and specifications of the powder collector is one of the key factors determining the yield and yield of the powder. The gas vapor can prepared spherical copper powder (FCu) whose average particle size is 35nm.

³-ray radiation preparation of various types of metal particles is a new method developed in recent years, its basic principle is that the metal salts reduced to metal particles in the ³-rays. ³-rays so that the solution to produce a solvated electron, without using a reducing agent can restore the metal ions, reducing its valence and the formation of metal particles by nucleation and growth. In recent years been used to prepare a variety of metal powders using Co source strength of ³-ray radiation was prepared metal ultrafine particles, and ³-ray radiation - the crystallization of the hydrothermal combined method of ultrafine copper powder with average particle size of 50nm.

Plasma of the Act of metal powders using plasma melting, evaporation into a gas, so that physical or chemical reactions in the gas state, and finally grew up condensation in the cooling process to form ultra-fine powders is of high purity, uniform series of small particle size metal and metal alloy series the most effective way of ultrafine particles. Plasma temperatures are high, fast response, will be uniform, small particles of ultra-fine powder, easy to implement mass production, can be prepared almost any superfine material.

Overall, the ultrafine copper powder preparation techniques are mostly still in the experimental stage of exploration, with industrialized mass production applications, there is a long journey, no matter what kind of preparation methods, has its own advantages, but also more or less of a problem. Physical method, gas steam method, device complexity and high cost; ³-ray method difficult to collect; plasma method energy utilization; water atomization prepared by product size, and formability. Chemical method, mechanical and chemical Preparation of copper powder uneven particle size distribution width and easy introduction of impurities; electrolysis energy consumption and high cost; ammonium disproportionation method the yield is too low; liquid phase chemical reduction equipment simple, easy to industrial production, but reducing agent used is either highly toxic, or the cost is too high.

Because of these shortcomings, the application and popularization of these preparation methods has been limited. Therefore, with deficiencies of the existing variety of preparation methods, metal powder supplier should begin its future research works in the following several aspects: to improve the equipment and processes, reduce energy consumption and waste. At the same time, it can learn from the other powder preparation method and production processes. Due to the smaller particle size of nano-copper powder and big surfactant, it is easy to reunite and the powder surface is easily oxidized to Cu2O. So how to improve the dispersion of nano-copper powder and how to prevent copper powder oxidization will be an important research direction. Source:http://www.mhcmp.com