Formaldehyde method
The copper sulfate is directly reduced by formaldehyde, and the obtained copper powder particles are coarse and have poor uniformity. Pre-reduction of copper sulfate with glucose, under alkaline conditions, reduction with formaldehyde to obtain a purple-red ultrafine copper powder with a particle size of 20 to 400 nm.
Using sodium as a reducing agent, copper sodium particles were prepared by liquid phase precipitation. Characterized by TEM and XRD, the particle morphology is spherical, the average particle size is about 30nm, the particle size distribution is narrow, the particle distribution is uniform, and there is no hard agglomeration, which is cubic cubic elemental copper powder. The surface of the copper powder is passivated. Improves the ability to resist oxidation. Can be stored in the air.
Hydration method
The copper sulfate solution in which the dispersing agent is dissolved is reacted with the hydrazine hydrate solution to obtain a copper powder having a particle diameter of about 10 nm, and the particle size distribution is uniform.
Ultrafine copper powders with different particle sizes (50-500/lm) were prepared with hydrazine hydrate as reducing agent. The preparation process of copper powder and the stability of copper powder with different particle sizes in air were studied. The glucose reduction method is used to improve the uniformity of copper powder obtained by direct reduction of hydrazine hydrate. As a dispersing agent, gelatin prevents particle agglomeration and controls the particle size of copper powder.
The copper salt is reduced by using hydrazine hydrate to obtain copper powder, and the addition of a polymer protective agent polyvinylpyrrole (PVP) alkanone is advantageous for stabilizing crystal grains and preventing agglomeration. Lisicecki et al. used a microemulsion method to prepare a nano-copper powder with an average particle size of 50 nm and good monodispersity by using hydrazine hydrate as a reducing agent.
Sodium hypophosphite
The complex solution of CuSO4 was reduced with NaH2PO2 to obtain elemental copper having a particle size of 30 to 50 nm. A certain concentration of sodium hypophosphite solution is added to a certain concentration of copper sulfate solution at a certain rate to stir, so that the two undergo oxidation-reduction reaction to produce elemental copper.
Boron hydride method
CuSO4 was reduced by KBH4, nano-sized copper powder was prepared by adding KOH and EDTA, and the concentration of the reactants was adjusted to eliminate impurities such as Cu: O. The prepared nano-copper powder still had some agglomeration, and the test was added with a dispersant to improve.
The complex solution of CuCI2 was reduced with a KBH4 solution to obtain a red-black copper powder having a particle size of about 20-40 nm.
Zinc powder reduction
Ultrafine copper powder can be prepared at low cost by chemical synthesis. The metal zinc and copper sulfate pentahydrate were used as raw materials to adjust the pH value with ammonia water. The effects of copper sulfate concentration, ammonia water addition amount and reaction temperature on the particle size of ultrafine copper powder were studied, and a 0.1 μm ultra-fine density was obtained. Copper powder.
Ascorbic acid method
Using CuSO4·5H2O as raw material, ascorbic acid as reducing agent and polyvinylpyrrolidine as protective agent to prepare 20-40 nm copper powder, and discussing the ratio of CuSO and ascorbic acid, the amount of protective agent (dispersant) and its copper The control of powder particles.