Initiation electroless nickel plating by atomic hydrogen for PCB final finishing

In this work, atomic hydrogen generated from decomposition of formaldehyde, is used to replace of Pd catalyst, because, according to Brenner and Hersch's model, atomic hydrogen as reaction intermediate can start electroless nickel plating. As the plated copper was removed out of the alkaline formaldehyde solution, its open circuit potential and Raman spectra were also studied, showing that the existence of atomic hydrogen adsorbed on the copper can last for a while until the formation of Cu2O. Then it was verified that electroless nickel could be started successfully by short-lived atomic hydrogen. The obtained nickel layers separately initiated by atomic hydrogen and Pd were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX); their anti-corrosion was also studied by potentiodynamic polarization and electrochemical impedance spectroscopy. The results demonstrate that atomic hydrogen is superior to Pd in starting electroless nickel plating for PCB final finishing. (C) 2016 Elsevier B.V. All rights reserved.