Effect of Phosphorus on the Structure of Nickel Electrocoatings

Abstract

The present work deals with the influence of sodium hypophosphite content in the plating bath on the chemical composition and structure of the obtained nickel electrocoatings. Electrodeposition of the Ni-P coatings was conducted under galvanostatic conditions at room temperature from the Watts type bath containing different amounts of sodium hypophosphite (0-30 g dm-3). The chemical and physical characteristics of the obtained Ni-P deposits and comparable Ni coating, were performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods. It was found that the addition of sodium hypophosphite as amorphizator to the Ni-plating bath influences both the structure and chemical composition of the obtained Ni electrodeposits. With increase in the content of sodium hypophosphite in the bath, surface morphology of the amorphous Ni-P coatings becomes more developed what is of key-importance for electroevolution of hydrogen on such electrodes.