Effect of Complexing Agent in Ni-P Coating on Cu Substrate

Complexing agent in the electroless nickel coating (Ni-P) solution plays an important role to maintain the coating deposition rate during the coating process. This paper studies the effect of two complexing agent; sodium citrate and sodium acetate in Ni-P coating. Ni-P coating was prepared in bath containing: NiSO4·6H2O, NaPO2H2·H2O, C2H5NO2, and Pb (NO3)2. Ni-P coating was coated on polished Cu substrate. Morphology, thickness and surface roughness of Ni-P coating were characterized using scanning electron microscope (SEM)/electron dispersive x-ray (EDX), optical microscope (OM), and atomic force microscopy (AFM). The result showed that sodium acetate have higher deposition rate up to 12 μm/h, whereas sodium citrate provided better surface morphology with lower surface roughness.