Preparation and Performance of Silver Coated Copper Powder

摘要

Different parameters are used to characterize the conductivity of copper powder with silver plating. Ethanediamine(C_2H_8N_2) is employed to adjust the pH value of plating solution (solution A), and chelate Cu~(2+) generated by side reaction, forming sound five-membered ring structure with Cu~(2+), thus preventing the formation of Cu(NH_3)_4~(2+) which can avoid adsorption of Cu(NH_3)_4~(2+) on the surface of copper powder. In this way silver-plated copper powder with conductivity equal to fine silver powder can be obtained, the effects of dosage of C_2H_8N_2 and Tollens' reagent concentration on performance of silver-plated copper powder have also been investigated. The result shows that dosage of C_2H_8N_2 has significant effects on electrical conductivity of silver-plated copper powder. The dosage of C_2H_8N_2 should ensure that pH value of control solution A maintains 9.0-10.0. The concentration of Tollens' reagent should make sure that the generated silver-plated copper powder is most even and continuous and tightness when silver particles in form of heterogeneous nucleation is surrounded on the surface of copper powder, , and the optimum concentration is 0.09mol/L. The conductivity of silver-plated copper powder made by Tollens' reagent with 0.09mol/L concentration is .iptimal, which is3.9 × 10~(-4) Ω?cm when adjusting the pH value of solution A to 9.5 by C_2H_8N_2 control.