Electrochemical Formation of Brazing Alloys on Metal Substrates


Ulu F., Karakaya I., Demirci G., Erdogan M.

Symposium on Fundamentals of Electrochemical Growth - From UPD to Microstructures 3 held during the 224th Meeting of the Electrochemical-Society (ECS), San-Francisco, Kostarika, 27 Ekim - 01 Kasım 2013, cilt.58, ss.61-69

  • Cilt numarası: 58
  • Doi Numarası: 10.1149/05832.0061ecst
  • Basıldığı Şehir: San-Francisco
  • Basıldığı Ülke: Kostarika
  • Sayfa Sayısı: ss.61-69

Özet

Cusil (TM) is a eutectic brazing alloy of 72% silver, 28% copper composition; used to join different materials. The large difference between the standard reduction potentials of silver (0.799V) and copper (0.337V) makes their electrochemical codeposition difficult. A complex ion bath containing KAg(CN)(2), CuCN and KCN was used to bring the reduction potentials closer together. The effect of electrolyte concentration on composition and microstructure of electrodeposited Ag-Cu films was investigated at 25 degrees C. A current density of 2 mA/cm(2) was used to codeposit copper and silver based on results of voltammetric studies. It was found that increasing KCN and KAg(CN)(2) and decreasing CuCN concentrations increased Ag contents of deposits. Surface morphology was spherical grained in general. Increasing Ag content of the deposits resulted in finer grained structures, but deposits containing higher Ag concentrations were found to develop dendritic structures especially after the initial deposition of the Ag-Cu alloy coating on the surface.