Effect of PDDA surfactant on the microstructure and properties of electrodeposited SiO2/Ni nanocomposites

Abstract

In this study, SiO2/Ni nanocomposite coatings were electrodeposited from a sulphate bath with and without the addition of polydiallydimethylammonium chloride (PDDA) as a cationic surfactant. The surface morphology and microstructure on the cross-sections of the deposited nanocomposites were examined by scanning electron microscopy. More detailed microstructure characterization was performed using transmission, scanning-transmission and high-resolution transmission electron microscopy. It was determined that the addition of 2 and 3 mL/L of PDDA allows the incorporation of well-dispersed SiO2 nanoparticles in the crystalline nickel matrix. The distribution of SiO2 nanoparticles in the nanocomposite was visualized on elemental maps using energy dispersive X-ray spectroscopy in scanning-transmission mode. The size of nickel grains was determined by means of XRD, as well as image analysis of TEM images. The volume fraction of SiO2 clusters in the SiO2/Ni+PDDA nanocomposites with the addition of 2 and 3 mL/L of PDDA was equal to 16 and 27%, respectively. It was determined that improved quality nanocomposites electrodeposited in the presence of 3 mL/L of PDDA and 8 g/L of SiO2 exhibit high nanohardness, as well as good tribological properties and corrosion resistance.