Abstract:The electroless deposition process of copper plating consisting of TEA and EDTA as complexing agents, paraformaldehyde as reducing agent, and 2-mercaptobenzothiozole as stabilizer and gelatin and animal glue as additives was investigated. The stability of the electroless copper solution was monitored by measuring the absorbance of the solution with a UV-Visible spectrophotometer and the solution was quite stable up to 15 h. The adhesion of copper films on mild steel foil was assessed by standard bend test and exhibited good adhesion. The XRD results indicate that the copper films have a (111) texture. Moreover, the additives suppress the predominant (111) plane crystal growth and increase the rate of (220) texture crystal growth. The crystal size of the copper films was calculated using the Scherrer formula from the predominant peak. SEM and AFM studies reveal that these two additives modify the crystal structure, grain size and surface morphology of the copper films. The cyclic voltammetry studies reveal that the additives are adsorbed on the electrode surface and inhibit the rate of deposition. Potentiodynamic polarization and electrochemical impedance studies reveal that the deposits produced in the presence of additives display higher corrosion resistance.

Key words: electroless copper; additives; potentiodynamic polarization; electrochemical impedance spectroscopy