The chemical reduction method of silver coated copper powder refers to the process of using a reducing agent to reduce the ions in the main salt to elemental form and depositing on the surface of the substrate with autocatalytic ability in a metastable solution system. When the reducing agent is oxidized on the catalytically active surface, free electrons are generated. These free electrons can reduce the metal ions in the solution on the catalytic surface. As long as the deposited metal layer has catalytic activity for the reducing agent, the metal can be continuously deposited . When the process conditions are constant, the plating layer with a specific thickness can be obtained through the control of time. The biggest advantage of electroless plating is that the thickness of the coating is uniform, the pinhole rate is low, and the thickness of the coating is controllable. The current process for electroless silver plating of copper powder uses steel atoms or other active atoms adsorbed on the surface of the copper powder as the nucleation catalyst center, so that the silver particles gradually nucleate and grow on the surface of the copper powder, thereby obtaining a continuous coating. , But the stability of the plating solution is poor, especially when some strong reducing agents (formaldehyde, hydrazine hydrate, etc.) exist in the plating solution, it is easy to fail and decompose, and the chemical reduction method of silver plating has a fast reaction speed and is not easy to control.
Reaction mechanism

Due to the high potential of silver ions, it can be reduced and deposited on the surface of copper powder under the action of many reducing agents such as glucose, formaldehyde, hydrazine sulfate, metol and dimethylamine borane. However, the stability of the electroless silver plating solution is poor and the service life is short, so a stabilizer must be added to prevent the plating solution from becoming turbid and decomposing. Commonly used stabilizers include sulfur compounds (including thiourea, thiosulfate, thiopropane sulfonate) and certain metal inorganic salts.

The reduction mechanism of silver ions in electroless plating is still controversial. One view believes that the deposition of silver is different from electroless nickel and copper plating. It is a non-catalytic process that first forms silver colloidal particles in the solution, and then condenses into a deposited layer. Another view is that the deposition process of silver still has autocatalysis, but its autocatalysis ability is not strong.

SAT NANO specializes in the production of silver coated copper powder, using different processes according to customer needs, and has achieved a better coating effect.