The oxidation of nano-copper powder is a problem that must be considered when applying nano-copper powder, and it has always been a topic of common concern for manufacturers and users. Generally, surface treatment of nano copper powder is required to improve its oxidation resistance and stability. There are four commonly used methods for surface treatment of nano copper powder:
1. Coupling agent method: Coupling agent is a surface modifier with both hydrophilic and lipophilic properties. It can also be used to improve the oxidation resistance of copper powder. The coupling agents used today are mainly silanes, followed by titanates and aluminates, in addition to chromium, zirconium compounds, higher fatty acids, alcohols, and esters.
2. Metal coating method: plating a layer of corrosion-resistant metal such as silver and nickel on the surface of nano-copper powder by electroless plating method can improve the oxidation resistance and high temperature resistance of nano-copper powder. It is currently the most researched and applied one. Kind of method. The preparation process is to add nano-copper powder to the solution of silver complex (such as silver-ammonia complex). The replacement reaction mainly occurs in the initial stage of the reaction. The electrons of the silver-ammonia ion on the surface of the nano-copper are reduced to form a dotted structure monomolecular silver plating Afterwards, the silver, copper and reaction solution on the copper surface gradually form tiny galvanic cells. As the effect of galvanic cells gradually becomes obvious, silver is continuously deposited on the surface of nano-copper, forming a multi-molecule silver-plated layer. The powder plays a protective role.
3. Organic acid coating method: Because copper in nano-copper powder has a high electrode potential, it is not corroded by non-oxidizing acids, and fatty acids, citric acid, salicylic acid and benzoic acid can not only remove nano-copper The oxide on the surface of the powder can also coat the surface of the nano-copper powder to form an anti-oxidation layer. The organic acid coating method generally adopts the soaking method.
4. Compounding agent corrosion inhibition method: azole compounds such as benzotriazole and mercaptobenzothiazole can make copper metals have excellent corrosion inhibition performance, and the molecules of these corrosion inhibitors contain nitrogen atom heterocycles.
For more questions about the preparation and application of nano-copper powder, please contact yosoar. This article is edited by Cindy.